Use of frequency division multiplexing in optical cardiac signals

Abstract

An electronic wearable device includes a housing configured to contact a user's skin, first and second modulators, first and second light emitters coupled with the first and second modulators, a light receiver, and a receive processing circuit. The first modulator and the second modulator output a first electronic signal having a first carrier frequency and a second electronic signal having a second carrier frequency. The first light emitter outputs a first light signal having a first carrier frequency into the skin of a user. The second light emitter outputs a second light signal having a second carrier frequency into the skin of the user. The optical receiver receives an optical signal from the skin as a broadband signal. The receiving processor circuit outputs a first photoplethysmogram signal corresponding to the first optical signal based on a first carrier frequency, and outputs a second photoplethysmogram signal corresponding to the second optical signal based on a second carrier frequency.

Description

Background Technology

[0001] Electronic wearable devices can provide optical cardiac monitoring for the user. The user can wear the electronic device with its housing positioned in contact with the user's skin—typically on the wrist. Cardiac monitoring can include physiological measurements and information such as the user's heart rate and pulse oxygen saturation.

[0002] Many conventional electronic wearable devices are body-worn devices, comprising a housing with a bottom wall containing light emitters (e.g., LEDs) that output (emit) light signals (light) to the user's limbs (such as the user's wrist) and light receivers (photodiodes) that receive the reflected light. Conventional devices typically include one or more processors that generate a photoplethysmography (PPG) signal associated with the intensity of the reflected light and use the generated PPG signal to determine physiological information about the user, including cardiac metrics such as the user's heart rate or blood oxygen saturation. Emitter arrays can form multiple light emitters, some of which emit light at wavelengths different from those emitted by others. Conventional devices generally house multiple emitter arrays and multiple light receivers at different locations on the bottom wall of the housing, allowing multiple light signals to travel different paths under certain conditions using different wavelengths of light. The techniques used to control the output of the light signals and the positioning of the optical components can affect the quality of the reflections received by the optical sensors and the corresponding PPG signals, potentially affecting the accuracy of the measurement and determination of information about the user's heart. Many optical layouts and topologies are known.

[0003] Conventional wearable electronic devices typically utilize time-division multiplexing to output light from different locations to one or more light receivers. Light transmitters that are close to each other do not emit simultaneously, as this time-division multiplexing technique usually results in only one light transmitter (close to the one or more light receivers) emitting light at any given moment. Each light transmitter is typically assigned a specific time slot to emit its light signal, and multiple light transmitters sequentially output multiple light signals over a long time period. For example, a five-millisecond (msec) time slot can be allocated to four light transmitters to emit light signals over a 20 msec time period, resulting in four sequential light transmissions from the four light transmitters within that 20 msec. Typically, the time slots of light transmitters that are close to each other do not overlap, causing each light transmitter to emit its light signal to the area of ​​the user's wrist during the time slot allocated to it (i.e., two light transmitters that are close to each other do not emit light simultaneously). Therefore, the PPG signal generated based on the electronic signal output by the light receiver (corresponding to the intensity of light reflected from the user's skin) has corresponding time slots, each time slot associated with one light transmitter emitting the light signal. Conventional electronic wearable devices that implement time-division multiplexing technology do not have optical transmitters that output optical signals continuously at the same time.

[0004] Reference Figure 1A Conventional wearable electronic devices may include optical devices such as light emitters that emit light signals into a user's skin and light receivers that receive the transmitted or reflected light signals from the skin and generate photoplethysmography (PPG) signals corresponding to the intensity of the received light signals. Typically, each light emitter emits a light signal at a constant intensity. Having multiple light emitters each emit light signals within one or more predetermined time slots provides greater accuracy and additional functionality when each light receiver receives light signals from all light emitters having a signal path to the corresponding light receiver and generates PPG electronic signals. Therefore, a signal processor can identify the source (light emitter) of each PPG electronic signal generated by each light emitter using one or more predetermined time slots for each light emitter.

[0005] like Figure 1B As shown, in order for the signal processor to associate each PPG electronic signal generated by the optical receiver with the optical transmitter, the signal processor typically retrieves from a memory element the time period (or time slot) during which each optical transmitter emits its optical signal, such as... Figure 1BAs shown. For example, a signal processor can configure a first optical transmitter (TX1) to output (transmit) its optical signal during a first time window (segment) before shutdown, configure a second optical transmitter (TX2) to output (transmit) its optical signal during a second time window (segment) before shutdown, and so on, until the Nth optical transmitter (TXN) has transmitted its optical signal during the Nth time window (segment). At this point, the process can be repeated whenever desired. When the signal processor determines which optical transmitter is configured to transmit its optical signal during any time period (such information can be stored in the memory), the signal processor can determine the source of the optical signal and the signal path from the optical transmitter to the optical receiver. This conventional technique for utilizing multiple optical transmitters is an example application of time-division multiplexing (TDM) optical signal transmission.

[0006] Although time-division multiplexing enables continuous transmission from multiple optical transmitters, the time required for all optical transmitters to be allocated time slots increases with the number of optical transmitters. Consequently, the time required for multiple optical transmitters to transmit their optical signals (all within their allocated time slots) can limit the rate at which one or more processors can determine information using PPG signals generated using reflections of light from the user's wrist. The duration of each transmission can also be related to the desired signal-to-noise ratio of the PPG signal, which may require each transmission of the optical signal to have a minimum duration for accurately determining physiological information about the user.

[0007] Furthermore, with the advent of improved optical techniques for determining user physiological information, there is an increasing desire to generate PPG signals optimally suited for determining user physiological information by outputting optical signals at multiple wavelengths within the electromagnetic spectrum, including the visible range (e.g., 520 nm wavelength or light that appears "green") and the infrared range (invisible to the human eye). Known applications of multi-wavelength PPGs include pulse spectroscopy, including pulse oximetry. Pulse oximetry typically requires the use of optical signals output at different wavelengths, such as a first wavelength between 600 nm and 700 nm and a second wavelength between 900 nm and 1000 nm, to generate the PPG signal. Of course, as the number of light emitters increases, the time period for generating each PPG signal decreases.

[0008] Therefore, conventional time-division multiplexing technology limits the number of optical signals that an optical transmitter can output independently or within an optical transmitter array to a series of optical transmissions. This series of optical transmissions generally results in an optical signal traveling along a signal path to an optical receiver in the user's skin area in each time period. There are separate time windows for each transmission and / or for the separation of the optical signal (along the signal path between the optical transmitter and the optical receiver) across the user's wrist area in each time period. Summary of the Invention

[0009] Embodiments of this technology provide an improved electronic wearable device, which (among others) includes: a plurality of optical transmitters, each configured to emit an optical signal having a predetermined carrier frequency; and a signal processor configured to control each optical transmitter to utilize the predetermined carrier frequency, thereby enabling frequency division multiplexing of optical signal transmission. This allows one or more (or all) of the optical transmitters to emit optical signals simultaneously and continuously. Such enhancement enables improved accuracy in determining physiological information such as a user's heart rate, pulse oximetry, and other parameters. Excluding power consumption and other considerations, the signal processor of this improved electronic wearable device can control the plurality of optical transmitters to simultaneously output optical signals, determine the optical transmitter from which it outputs an optical signal corresponding to a PPG electronic signal, and the signal path of the optical signal along its journey to the optical receiver using a stored predetermined carrier frequency, select a signal path by determining which PPG electronic signal corresponds to the selected signal path, and determine information about the user based on the determined PPG electronic signal corresponding to the selected signal path.

[0010] An exemplary wearable electronic device may generally include a housing, a first modulator, a second modulator, a first light emitter, a second light emitter, a light receiver, a first receiver processor circuit, and a second receiver processor circuit. The housing includes a bottom wall configured to contact a user's skin. The first modulator is configured to output a first modulated electronic signal having a first carrier frequency. The second modulator is configured to output a second modulated electronic signal having a second carrier frequency. The first light emitter is coupled to the first modulator, positioned on the bottom wall, and configured to output the first light signal into the user's skin, wherein the first light signal has the first carrier frequency. The second light emitter is coupled to the second modulator, positioned on the bottom wall, and configured to output the second light signal into the user's skin, wherein the second light signal has the second carrier frequency. The light receiver is positioned on the bottom wall and configured to receive the first and second light signals from the user's skin as broadband electronic signals, and output broadband electronic signals including the first and second light signals respectively associated with the first and second carrier frequencies. The first receiver processor circuit is configured to receive a broadband electronic signal and output a first photoplethysmography (PPG) electronic signal corresponding to the first optical signal based on a first carrier frequency. The second receiver processor circuit is configured to receive a broadband electronic signal and output a second PPG electronic signal corresponding to the second optical signal based on a second carrier frequency.

[0011] Another exemplary electronic wearable device may generally include a housing, a first modulator, a second modulator, a first light emitter, a second light emitter, a light receiver, an analog-to-digital converter, a memory element, and a processor. The housing includes a bottom wall configured to contact a user's skin. The first modulator is configured to output a first modulated electronic signal having a first carrier frequency. The second modulator is configured to output a second modulated electronic signal having a second carrier frequency. The first light emitter, coupled to the first modulator, is positioned on the bottom wall and configured to output a first light signal into the user's skin, wherein the first light signal has the first carrier frequency. The second light emitter, coupled to the second modulator, is positioned on the bottom wall and configured to output a second light signal into the user's skin, wherein the second light signal has the second carrier frequency. The light receiver is positioned on the bottom wall and configured to receive the first and second light signals from the user's skin as broadband electronic signals, and output a broadband electronic signal comprising the first and second light signals respectively associated with the first and second carrier frequencies. An analog-to-digital converter is configured to receive an analog broadband electronic signal and output the analog broadband electronic signal as a digital data stream corresponding to a first optical signal and a second optical signal. A memory element is configured to store a first carrier frequency corresponding to the first optical signal and a second carrier frequency corresponding to the second optical signal. A processor is configured to receive a digital broadband electronic signal comprising a first optical signal having a first carrier frequency and a second optical signal having a second carrier frequency, generate a first filtered electronic signal and a second filtered electronic signal having the first carrier frequency and the second carrier frequency, respectively, demodulate the first filtered electronic signal and the second filtered electronic signal by removing the first carrier frequency and the second carrier frequency, respectively, and output a first PPG electronic signal and a second PPG electronic signal corresponding to the demodulated first filtered electronic signal and the demodulated second filtered electronic signal, respectively.

[0012] This summary is provided to illustrate the choice of concepts in a simplified form, which are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. Other aspects and advantages of this technology will become apparent from the following detailed description of embodiments and the accompanying drawings. Attached Figure Description

[0013] Embodiments of the present technology are described in detail below with reference to the accompanying drawings, wherein:

[0014] Figure 1A This is a schematic block diagram of a prior art circuit of multiple optical transmitters that output optical signals, which are received by multiple optical receivers of a wrist-worn electronic device and used to generate photoplethysmography (PPG) signals.

[0015] Figure 1B It is something that happens within a certain time period and is used to achieve [the goal]. Figure 1A A graph of multiple optical transmissions in a time-division multiplexing transmission scheme of existing circuitry;

[0016] Figure 2 This is a top view of an electronic wearable device constructed according to various embodiments of the present technology, the electronic wearable device being worn on a user's wrist;

[0017] Figure 3 This is a bottom view of an electronic wearable device, illustrating multiple light emitters and multiple light receivers on the bottom wall of the device's casing.

[0018] Figure 4 This is a cross-sectional view of an electronic wearable device cut along a vertical plane, illustrating a light emitter that emits light signals that pass through and / or are reflected by the user's skin and received by a light receiver;

[0019] Figure 5 It is a schematic block diagram of the various electronic components of a wearable electronic device;

[0020] Figure 6A This is a schematic block diagram of multiple circuits and devices for realizing the transmission signal stream of an electronic wearable device, illustrating multiple modulators and multiple light emitters that enter the user's skin and whose output is received by at least one of multiple light receivers.

[0021] Figure 6B This is a schematic block diagram of multiple circuits and devices for an electronic wearable device that realizes the received signal stream. It illustrates multiple receiver processor circuits that filter and demodulate optical signals received from a user's skin by one or more optical receivers to generate PPG electronic signals.

[0022] Figure 7 It is a graph of the amplitudes of the carrier frequencies of multiple filters;

[0023] Figure 8 It is a schematic block diagram of multiple optical transmitters and optical receivers that realize the transmission and reception of signal streams;

[0024] Figure 9A It is a schematic block diagram of multiple optical transmitter arrays and multiple optical receivers, illustrating the path of optical signals emitted by each optical transmitter and received by multiple optical receivers;

[0025] Figure 9B yes Figure 9A A schematic block diagram of multiple optical emitters in a single optical emitter array;

[0026] Figure 9C It is by Figure 9BA graph of estimated blood absorption versus wavelength of the light signal output from a single light emitter;

[0027] Figure 9D It shows the relationship with Figure 9A A table showing exemplary wavelengths, carrier frequencies, and signal paths for optical signals corresponding to certain optical transmitters and receivers depicted in the figure; and

[0028] Figure 10 This is a flowchart of at least a portion of the steps in a process of filtering and demodulating a broadband electronic signal received from a user's skin to generate a PPG electronic signal, according to embodiments of the present technology.

[0029] The accompanying drawings do not limit the technology to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, but are intended to clearly illustrate the principles of the technology. Detailed Implementation

[0030] The following detailed description of this technology is taken with reference to the accompanying drawings, which illustrate specific embodiments in which the technology can be practiced. These embodiments are intended to describe aspects of the technology in sufficient detail to enable those skilled in the art to practice it. Other embodiments may be utilized and changes may be made without departing from the scope of the technology. Therefore, the following detailed description is not to be regarded as limiting. The scope of the technology is defined by the appended claims together with the full scope of the equivalents to which such claims are given. Furthermore, the term "voltage" can be used to describe electrical voltage, and the term "current" can be used to describe electrical current.

[0031] Reference Figure 1AConventional wrist-worn electronic wearable devices typically include circuitry and components such as drivers, switches, at least a first light emitter (TX) and a second light emitter, at least a first light receiver (RX) and a second light receiver, and multiplexers to generate an output light signal that enters the user's skin, is received by multiple light receivers, and is used to generate a PPG (photoplethysmography) electronic signal. The PPG electronic signal can be used to determine physiological information about the user. This physiological information may include measurements of the user's pulse or heart rate, pulse oxygen saturation ("pulse Ox") levels (also known as oxygen saturation or SpO2 levels), estimated stress levels, maximum oxygen consumption (VO2 max), etc. Typically, a signal processor in a conventional wrist-worn electronic wearable device controls the operation of each of the multiple light emitters and stores information such as the power level and time window of the light signal output by each light emitter in the device's memory elements. The signal processor then uses this information to determine and identify one of the multiple light emitters configured to emit its light signal during a given time period when the light receivers receive the light signal from the user's skin. A conventional wrist-worn electronic wearable device's signal processor can identify the signal path from one of multiple light emitters to a light receiver by using a determined source of the light signal. This conventional time-division multiplexing (TDM) technology, used to utilize multiple light emitters, allows the signal processor to control multiple light emitters, selecting their positions and the wavelength of the light signal desired to be output into the user's skin at a specified time. As the number of light transmission sequences increases, the duration required for all transmissions to occur increases, which lengthens the minimum time interval between consecutive light signal transmissions in the sequence. Furthermore, such a conventional TDM technology limits the number of light signals that can be output by multiple light emitters to a sequence in which only one light signal, output by only one of the multiple light emitters, travels along the signal path to the light receiver in the user's skin region within each time interval. Therefore, for each transmission, there is a separate time window, and in some cases, simultaneous light transmissions require separating the area of ​​the user's wrist that the simultaneously output light signals in each time period can pass through (along the signal path between the light transmitter and the light receiver) so that the signal processor of a conventional wrist-worn electronic wearable device can identify and recognize one of the multiple light transmitters that is configured to emit its light signal near the light receiver that receives the light signal from the user's skin during the time period of receiving the light signal.

[0032] A typical driver in a wrist-worn electronic wearable device usually outputs a driver electronic signal, which is generally a constant current level fixed during the sampling period. A switch typically electrically couples the driver to multiple light emitters positioned on the bottom wall of the wrist-worn electronic wearable device. In some cases, the switch receives the driver electronic signal and, depending on control settings, outputs the driver electronic signal to a first or second light emitter. These control settings select to direct the driver electronic signal to the first light emitter using its first output port, or select to direct the driver electronic signal to the second light emitter using its second output port. Once the first light emitter receives the driver electronic signal, it outputs (emits) a first light signal into the user's wrist. Similarly, once the second light emitter receives the driver electronic signal, it outputs (emits) a second light signal into the user's wrist. Each light signal is formed by electromagnetic radiation having wavelengths in the violet, visible, and / or infrared spectra, and has a light intensity level corresponding to the current level of the driver electronic signal. The light signals pass through and / or are reflected from the user's skin (human tissue), where they are modified, influenced, or otherwise impeded by the amount or flow of blood or other characteristics of the blood vessels in the signal path of the light signals. Specifically, in response to the user's heartbeat or cardiac cycle, the light signals are modified, influenced, or otherwise impeded by the flow of blood. After interaction with the user's skin, the light signals are received by a first and a second light receiver of a conventional wrist-worn electronic wearable device. The first light receiver typically outputs an analog first PPG electronic signal corresponding to the intensity of the received light signal, and the second light receiver typically outputs an analog second PPG electronic signal corresponding to the intensity of the received light signal. A multiplexer of the conventional wrist-worn electronic wearable device receives each of the PPG electronic signals and outputs one selected of the PPG electronic signals according to control settings. In some cases, the conventional wrist-worn electronic wearable device includes an analog-to-digital converter to convert one or more of the device's analog electronic signals into digital data values ​​or digital data value streams.

[0033] Typically, multiple light emitters are used for several reasons. The first reason is to position multiple light emitters at various locations relative to one or more light receivers, allowing the light signal to travel along certain desired signal paths through the user's skin to the one or more light receivers. Since PPG electron signals traveling along different light signal paths can have different characteristics, the diversity of signal paths can increase the accuracy of the physiological information determined using PPG electron signals when combined for analysis. The second reason is to provide additional information about the user's cardiac parameters. For example, different wavelengths of light signals can be used to determine the user's pulse oxygen saturation ("pulse Ox") level (blood oxygen saturation or SpO2), maximum oxygen consumption (VO2 max), etc. The signal processor that receives and uses PPG electron signals to determine the user's physiological information may need to identify the source (light emitter) of each PPG electron signal, determine the wavelength of the light signal, the signal path along which the light signal travels, and when the light emitter outputs the light signal in order to perform the analysis necessary to determine the user's physiological information.

[0034] Therefore, existing electronic wearable devices utilize time-division multiplexing (TDM) optical signal transmission technology, in which each optical transmitter outputs its optical signal during one period of multiple predetermined time windows. (See reference...) Figure 1B The processor can control a first light emitter (TX1) to output its light signal during a first time window, control a second light emitter (TX2) to output its light signal during a second time window, and so on, until each light emitter (TXN) has output its light signal, at which point the process repeats. Each time window is typically a short period of time, such as less than 1 millisecond or 5 milliseconds. The processor in a typical wrist-worn electronic wearable device typically controls each light emitter to generate a light signal at a desired fixed or constant (DC) intensity level (light signals of different amplitudes can be output by multiple light emitters).

[0035] The TDM optical signal transmission method presents a dilemma. The goal is to keep each optical transmitter on for as long as possible to transmit optical signals, achieving the highest signal quality and allowing the processor time to process information from the PPG electronic signals. However, the longer any one optical transmitter is on, the longer all other optical transmitters are off. Therefore, completing more optical signal transmission cycles to improve the accuracy of physiological information determined using PPG electronic signals, in order to collect continuous data for a longer duration in each optical signal transmission cycle, conflicts with outputting each optical signal over an extended duration, which would prolong the time required for all optical transmitters to output signals within their respective time windows. Similarly, completing more optical signal transmission cycles to collect continuous data for a longer duration in each optical signal transmission cycle conflicts with outputting signals over a shorter duration, which would reduce the time required for all optical transmitters to output signals within their respective time windows. These conflicts ultimately limit the number of optical transmitters the processor can control to output optical signals to a single optical receiver and the duration of each optical signal transmission. For example, refer to... Figure 1B If "N" is the fifth light emitter, and the duration of each of the five time windows is 1 millisecond, then a complete transmission sequence will occur within 5 milliseconds, and three transmission sequences will be completed within 15 milliseconds. The accuracy of the psychological information determined using PPG electronic signals will be improved if each of the five light emitters can simultaneously or continuously (compared to the example above, causing all five light emitters to transmit light signals simultaneously within 1 millisecond) or for a predetermined duration within a power-limiting timeframe, into a common area of ​​the user's skin.

[0036] Embodiments of the present invention utilize the modulation of optical signals with different (non-overlapping), predetermined frequencies, signal phases, and / or waveforms to enable the multiplexing of a larger number of optical signals. Specifically, the processor of an electronic wearable device can control multiple modulators to achieve a modulation function that produces an output of a modulated electronic signal with a predetermined frequency, phase, and / or waveform. This modulated electronic signal output enables each optical signal and each optical transmitter from which it outputs the optical signal to be distinguishable from optical signals output by other optical transmitters. For each optical signal received by a light receiver, the processor can determine the light transmitter from which it outputs the optical signal, the signal path along which the optical signal travels through the user's skin, and physiological information about the user, based on the optical signal and the determined signal path along which the optical signal travels through the user's skin.

[0037] For example, in embodiments, the improvements disclosed herein enable a processor to control a modulator to generate carrier signals with different frequencies and to control multiple light emitters (e.g., LEDs) such that all light emitters can output light signals on multiple signal paths. The duration of the light signal output by each light emitter can be continuous or limited to a time period that meets applicable signal-to-noise ratio requirements to accurately determine information about the user's heart. For example, a modulator or electronic circuitry system coupled to multiple light emitters can modulate the drive current input to each light emitter so that the output light signal includes a carrier frequency that may be different from the carrier frequency associated with the other light emitters. As the light signal output by each light emitter passes through tissue on the upper surface of the user's skin, such as the upper layer of skin on the user's wrist, blood attenuates the light signal (typically, the amplitude of the modulated light signal reflects the volume or concentration of blood present in the area and / or layer of the user's skin tissue), and a light receiver (e.g., a photodiode) outputs a signal that, once demodulated, results in the generation of the user's PPG electronic signal, which corresponds to the amplitude of the received light signal (at a given carrier frequency) and is used by the signal processor to determine physiological information about the user. An optical receiver that receives multiple optical signals, each having a predetermined carrier frequency, outputs a broadband optical signal comprising multiple optical signals each associated with a carrier frequency. The use of a unique carrier frequency corresponding to the location and wavelength of a specific optical transmitter enables a signal processor to evaluate and process each demodulated PPG electronic signal output by the optical receiver, and to identify and select the optical transmitter from which each signal originates. In an embodiment, the signal processor may determine and utilize the optical signal associated with the PPG electronic signal along its traversed signal path (from the optical transmitter to the optical receiver) to select the PPG electronic signal used to determine physiological information about the user.

[0038] Therefore, in an embodiment, the processor can be configured to control multiple optical transmitters to output optical signals either continuously or simultaneously for a predetermined duration, receive one or more broadband electronic signals from one or more optical receivers, filter and demodulate the broadband electronic signals to generate PPG electronic signals, and use a stored predetermined carrier frequency to determine the optical signal output from each PPG electronic signal and the signal path of the optical signal along its journey to the optical receiver, which receives the optical signal containing the optical signal associated with the predetermined carrier frequency. In an embodiment, the processor can be configured to select one or more signal paths and the associated PPG electronic signals for determining physiological information about the user. The processor is configured to control each optical transmitter to enable frequency division multiplexing of the optical signals emitted by the multiple optical transmitters using the predetermined carrier frequency, which allows the processor to control one or more (or all) optical transmitters to output optical signals simultaneously and continuously. Such enhancement enables improved accuracy in determining physiological information such as the user's heart rate, pulse oxygen saturation, and other parameters.

[0039] Reference Figures 2 to 8 Embodiments of this technology provide an electronic wearable device that is typically worn on a user's wrist or otherwise secured to the user's skin at different parts of the user's body. This allows multiple light emitters to simultaneously or continuously output light signals into a common area of ​​the user's skin for a predetermined duration. The electronic wearable device includes multiple light emitters, each emitting a light signal having a wavelength and a periodic waveform with a predetermined (selectively unique) carrier frequency. That is, a first light emitter emits a first light signal with a first carrier frequency, a second light emitter emits a second light signal with a second carrier frequency different from the first carrier frequency, and so on for each light emitter. This configuration allows the source light emitter of each light signal to be uniquely identified by its carrier frequency, which in turn allows all light signals to be transmitted continuously or as desired simultaneously, taking into account the signal path from the light emitter to the light receiver when determining physiological information about the user.

[0040] The wearable electronic device also includes multiple optical receivers, each receiving light signals passing through and / or reflected from the user's skin as a broadband electronic signal comprising the light signals. It should be understood that each optical receiver receives a broadband electronic signal containing light signals associated with different carrier frequencies, and the processor is configured to receive multiple analog broadband electronic signals (each received from and output by the optical receivers) from a receiver-side multiplexer, and to convert (digitize) each analog broadband electronic signal into a digital broadband electronic signal using an analog-to-digital converter (ADC).

[0041] Electronic wearable devices may also include multiple receiver processor circuits—typically, one receiver processor circuit for each optical signal received by the optical receiver. Each receiver processor circuit receives a broadband electronic signal, filters out signals other than the optical signal having a carrier frequency, demodulates the filtered signal to extract the amplitude of the carrier frequency, and outputs a PPG electronic signal that includes the characteristics imparted to the optical signal due to travel across the user's skin.

[0042] Alternatively, the electronic wearable device may also include an analog-to-digital converter and a processor, the analog-to-digital converter being configured to receive an analog broadband electronic signal output from a light receiver and output a broadband electronic signal as a digital data value stream corresponding to the broadband electronic signal, the processor filtering the broadband electronic signal and demodulating the filtered optical signal to output a PPG electronic signal, the PPG electronic signal including characteristics imparted to the optical signal due to travel across the user's skin.

[0043] Components of wearable electronic devices provide frequency division multiplexing (FDM) optical signal transmission, where optical transmitters can operate simultaneously and continuously, or for a predetermined duration with limited power consumption, thereby allowing for improved accuracy of the processor in determining user physiological information using PPG electronic signals. The processor is configured to determine physiological information about the user based on one or more selected PPG electronic signals and an optical signal associated with each selected PPG electronic signal along its signal path from the optical transmitter to the optical receiver. For example, the processor can be configured to determine physiological information about the user based on PPG electronic signals associated with optical signals traveling along substantially perpendicular signal paths. In such an example, the processor can select an optical transmitter and an optical receiver from which the optical signals will travel along substantially perpendicular paths, determine a predetermined carrier frequency associated with the selected optical transmitter, select a PPG electronic signal corresponding to the predetermined carrier frequency, and determine physiological information about the user based on the selected PPG electronic signals. In one embodiment, the electronic wearable device may include thirty-two optical transmitters, and the processor may be configured to selectively control each optical transmitter to output an optical signal having one of thirty-two predetermined carrier frequencies (or signal phases and / or waveforms) to enable multiplexing of the optical signals output by the thirty-two optical transmitters.

[0044] Embodiments of the technology will now be described in more detail with reference to the accompanying drawings. An exemplary electronic wearable device 10 can be implemented as a smartwatch or wearable strap typically worn on a user's wrist, but can also be implemented as a band or strap worn on the skin of a user's arm, leg, torso, or other part of the user's body. Other examples of the electronic wearable device 10 may include a smartphone, personal data assistant, etc., which includes a surface that can be pressed against the user's skin for holding optical devices. (Refer to...) Figures 2 to 5 The electronic wearable device 10 generally includes a housing 12, a wristband 14, a display 16, a user interface 18, a communication element 20, a location determination element 22, a memory element 24, and a processor 26. The electronic wearable device 10 also includes a plurality of light emitters 28 and a plurality of light receivers 30 on the bottom wall of the electronic wearable device 10. In an embodiment, the electronic wearable device 10 includes an optical signal processing circuit system.

[0045] like Figure 2 , Figure 3 and Figure 4 As shown, housing 12 typically houses or holds other components of wearable electronic device 10 and may include or be attached to a wristband 14. Housing 12 may include a bottom wall, a top surface, and at least one side wall defining an internal cavity (not shown). The bottom wall includes a lower outer surface that contacts user skin, such as the upper layer of the user's wrist, when the user is wearing the wearable electronic device 10. The top surface is opposite the bottom wall. In various embodiments, the top surface may also include an opening extending from the top surface to the internal cavity. In some embodiments, such as the exemplary embodiment shown in the figure, the bottom wall of housing 12 may have a circular, annular, or elliptical shape with a single circumferential side wall. In other embodiments, the bottom wall may have a quadrilateral or other polygonal shape, such as a square or rectangle, wherein housing 12 includes four or more side walls. (Refer to...) Figure 3 and Figure 4 The bottom wall may include one or more openings for placing, setting, or positioning a plurality of light transmitters 28 and a plurality of light receivers 30. These openings within the bottom wall may be covered by one or more lenses (not shown) through which light signals can be transmitted and received.

[0046] like Figure 2 As shown, display 16 typically presents information such as the time of day, current location, etc., as mentioned above. Display 16 can be implemented using one of the following technologies: light-emitting diode (LED), organic LED (OLED), light-emitting polymer (LEP) or polymer LED (PLED), liquid crystal display (LCD), thin-film transistor (TFT) LCD, LED side-lit or backlit LCD, etc., or combinations thereof. In some embodiments, display 16 may have a circular, annular, or elliptical shape. In other embodiments, display 16 may have a square or rectangular aspect ratio that can be observed in the horizontal or vertical orientation.

[0047] User interface 18 typically allows users to interact directly with the wearable electronic device 10 and may include buttons, rotary knobs, crowns, etc. In various embodiments, display 16 may also include a touchscreen occupying the entire display 16 or a portion thereof, such that display 16 serves as at least a part of user interface 18. The touchscreen allows users to interact with the wearable electronic device 10 by physically touching, swiping, or making gestures on an area of ​​display 16.

[0048] Communication element 20 typically allows communication with external systems or devices. Communication element 20 may include signal and / or data transmission and reception circuitry such as antennas, amplifiers, filters, mixers, oscillators, digital signal processors (DSPs), etc. Communication element 20 can establish communication wirelessly using radio frequency (RF) signals and / or data compliant with communication standards such as cellular 2G, 3G, 4G, LTE, or 5G; IEEE 802.11 standards such as Wi-Fi; IEEE 802.16 standards such as WiMAX; Bluetooth™; or combinations thereof. Additionally, communication element 20 can utilize communication standards such as ANT, ANT+, Bluetooth™ Low Energy (BLE), and the 2.4 GHz Industrial, Scientific, and Medical (ISM) band. Alternatively, or additionally, communication element 20 can establish communication via a connector or coupler receiving a metal conductor wire or cable compatible with networking technologies such as Ethernet. In some embodiments, communication element 20 may also be coupled to a fiber optic cable. The communication element 20 can communicate electronically with the memory element 24 and the processor 26.

[0049] Location determination element 22 typically determines the current geographic location of wearable device 10 and can receive and process radio frequency (RF) signals from multi-constellation Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS) used in the United States, the Galileo system used in Europe, and the GLONASS system used in Russia. Location determination element 22 may be accompanied by or include an antenna to assist in receiving satellite signals. This antenna may be a patch antenna, a linear antenna, a loop antenna, a slot antenna, or any other type of antenna that can be used with positioning or navigation equipment. Location determination element 22 may include a satellite navigation receiver, a processor, a controller, other computing devices, or a combination thereof, and memory. Location determination element 22 can process location electronic signals transmitted from the antenna, which receives location radio signals from one or more GNSS satellites. The location radio signals include data from which geographic information, such as the current geographic location, is derived. The current geographic location may include coordinates such as latitude and longitude of the current location of wearable device 10. Location determination element 22 may transmit the current geographic location to processor 26, memory element 24, or both.

[0050] While embodiments of the location determining element 22 may include a satellite navigation receiver, it should be understood that other location determining techniques may be used. For example, a cellular tower or any custom-designed transmitting radio frequency tower may be used instead of a satellite to determine the location of the wearable device 10 by receiving data from at least three transmitting locations and then performing basic triangulation calculations to determine the device's relative position to the transmitting locations. Using such a configuration, any standard geometric triangulation algorithm can be used to determine the location of the wearable device 10. The location determining element 22 may also include or be coupled to a pedometer, accelerometer, compass, or other dead reckoning component that allows it to determine the location of the wearable device 10. The location determining element 22 may determine its current geographic location via a communication network (such as by using Assisted GPS (A-GPS)) or from another wearable device. The location determining element 22 may even receive location data directly from the user.

[0051] Memory element 24 may be implemented by a device or component that typically stores data and specifically stores digital or binary data, and may include exemplary electronic hardware data storage devices or components such as read-only memory (ROM), programmable ROM, erasable programmable ROM, random access memory (RAM) (such as static RAM (SRAM) or dynamic RAM (DRAM)), cache memory, hard disk, optical disk, flash memory, thumb drive, universal serial bus (USB) drive, solid-state memory, etc., or combinations thereof. In some embodiments, memory element 24 may be embedded in processor 26 or packaged in the same package as the processor. Memory element 24 may include, constitute, or implement a non-transitory "computer-readable medium". Memory element 24 may store instructions, code, code statements, code segments, software, firmware, programs, applications, services, daemons, etc., executed by processor 26. Memory element 24 communicates electronically with processor 26 and may also store optical signals output by each optical receiver, carrier frequencies corresponding to each optical transmitter (and optical signals output by the optical transmitters), and data received by processor 26 or a device in which processor 26 is implemented. The processor 26 can also store data or intermediate results generated during processing, operation, and / or calculation, as well as data or final results after processing, operation, and / or calculation. Additionally, the memory element 24 can store settings, databases, etc.

[0052] Processor 26 may include one or more processors. Processor 26 may include electronic hardware components such as microprocessors (single-core or multi-core), microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), analog and / or digital application-specific integrated circuits (ASICs), intelligent circuit systems, or combinations thereof. Processor 26 typically executes, processes, or runs instructions, code, code segments, code statements, software, firmware, programs, applications, processes, services, daemons, etc. Processor 26 may also include hardware components such as registers, finite state machines, sequential and combinational logic, configurable logic blocks, and other electronic circuitry necessary to perform the operations of this technology. In some embodiments, processor 26 may include multiple computing units and functional blocks that are individually packaged but function as a single unit. In some embodiments, processor 26 may also include multiprocessor architectures, parallel processor architectures, processor clusters, etc., providing high-performance computing. Processor 26 may communicate electronically with other electronic components of the wearable electronic device 10 via serial or parallel links including general-purpose buses, address buses, data buses, control lines, etc. Additionally, processor 26 may include an analog-to-digital converter (ADC) for converting analog electronic signals into digital data values ​​or digital data value streams, and / or a digital-to-analog converter (DAC) for converting digital data values ​​or digital data value streams into analog electronic signals.

[0053] Reference Figure 6A and Figure 6B The diagram illustrates the transmit and receive signal flows. In addition to multiple optical transmitters 28 and multiple optical receivers 30, the electronic wearable device 10 also includes multiple modulators 32, multiple multiplexers 34 (MUX), and multiple receive processor circuits 36. The transmit signal flow includes multiple modulators 32 and multiple optical transmitters 28 that output optical signals received by at least one of the multiple optical receivers 30 and entering the user's skin. The receive signal flow includes multiple receive processor circuits 36 that filter and demodulate the optical signals received from the user's skin by one or more optical receivers 30 to generate PPG electronic signals. It should be understood that the processor 26 can execute, process, or run instructions to perform functions described herein with respect to the receive processor circuit 36, such as converting analog optical signals output by the multiple optical receivers 30 into digital data values ​​or streams of digital data values ​​of the optical signals using an internal or external analog-to-digital converter (ADC).

[0054] Each modulator 32 includes a circuit system such as a signal generator, signal amplifier, signal filter, etc., configured to output a modulated electronic signal having a periodic waveform with a carrier frequency. For example, modulator 32 may include a signal generator that outputs a periodically varying voltage and a transconductance amplifier that receives the voltage and converts it into a periodically varying current. The amplitude of the varying current is selected according to the electrical characteristics of each optical transmitter 28. The carrier frequency is selectively variable and is typically out of band for human biological signals of about 4 Hz or less. Therefore, the carrier frequency value can range from approximately 1 kHz to approximately 10 kHz or greater. The waveform can have a shape selected from a variety of shapes including sine, square, triangle, etc. Each modulator 32 is controlled by a processor 26, which can transmit program control signals to each modulator 32 to select the carrier frequency of the modulated electronic signal. The processor 32 can store the carrier frequency that can be selected for each modulator 32 corresponding to one or more optical transmitters 28 in a memory element 24. The program control signals output by processor 32 can also select the type of waveform used for the modulated electronic signals. In some embodiments, the electronic wearable device 10 may include a modulator 32 for each light emitter 28. In other embodiments, the electronic wearable device 10 may include circuitry for multiplying or otherwise modifying the modulated electronic signals to generate multiple modulated electronic signals for the multiple light emitters 28. Processor 26 can also control the timing of when each modulator 32 will output a modulated electronic signal and other parameters of each modulator 32.

[0055] Each multiplexer 34 includes an electronic circuit system, such as active and / or passive switching elements, capable of being configured or programmed to receive electronic signals and pass them to one of a plurality of outputs. Each multiplexer 34 includes a plurality of input ports and a plurality of output ports, wherein each input signal can be routed to any one of the output ports. The processor 26 outputs a programmable control signal to each multiplexer 34 to select an output port for each input signal. In an embodiment, the electronic wearable device 10 includes a first multiplexer 34 for operation in a transmitted signal stream and a second multiplexer 34 for operation in a received signal stream. The first multiplexer 34 is configured to electrically couple an input port for each modulator 32 to an output port for each optical transmitter 28. Similarly, the second multiplexer 34 is configured to electrically couple an input port for each optical receiver 30 to an output port for each receive processor circuit 36. In one embodiment, a second multiplexer 34 that receives broadband electronic signals from an optical receiver 30 can output the electronic signals to a transimpedance amplifier that receives periodically changing current and converts it into voltage.

[0056] Each light emitter 28 includes an electronic device such as a light-emitting diode (LED) or other short-wavelength EM radiation emitting device, configured to receive an electronic signal (typically a varying current) and emit or output (transmit) an optical signal comprising light, i.e., EM radiation corresponding in amplitude and frequency to the electronic signal and having a wavelength (λ) in the ultraviolet, visible, or infrared spectrum. The photon generator of each light emitter emits or outputs electromagnetic radiation with a specific wavelength (optical signal) in the visible spectrum, near-infrared spectrum, or in the wavelength range of 1,000 nm to 1,500 nm, where the visible spectrum is typically between approximately 400 nanometers (nm) and 700 nm, and the near-infrared spectrum is typically between approximately 700 nm and 1,000 nm. The wavelength of the optical signal is typically determined by or varies according to the material used to form the photon generator of each light emitter. For example, optical signals with wavelengths between 500 nm and 600 nm are associated with the visually perceived color green. In some embodiments, some of the light emitters 28 may output optical signals with the same wavelength. In other embodiments, each of the plurality of light emitters 28 can output light signals with different wavelengths, such as Figure 8 As shown in the image.

[0057] Each light receiver 30 includes an electronic device such as a photodiode, photoresistor, or phototransistor, configured to output or modify electrical characteristics based on the intensity of EM radiation (i.e., light signals) incident on the device. For example, each light receiver 30 may receive the transmission or reflection of light signals from the skin and output a current corresponding to (and varying according to) the intensity of the received light signal. Specifically, the light receiver 30 outputs a broadband electronic signal having an amplitude and frequency that vary according to the amplitude and frequency (i.e., carrier frequency) of the received light signal. In embodiments of the electronic wearable device 10, the light receiver 30 approaches the light signal from all light emitters 28 adjacent to the light receiver 30, such that each light signal travels from the light emitter 28 to the light receiver 30 along a different signal path. In this case, the light receiver 30 functions as a signal mixer, causing the amplitude and frequency of the broadband electronic signal to vary according to the component light signals (including the frequencies of all light signals received by the light receiver 30). Furthermore, the light receiver 30 is sensitive to EM radiation in a wavelength range including wavelengths in the ultraviolet, visible, and infrared spectra.

[0058] In an embodiment, each PPG processor circuit 36 ​​receives a broadband electronic signal from an optical receiver 30 or a receive multiplexer 34 and outputs a PPG electronic signal. The PPG processor circuit 36 ​​may include a filter 38, a demodulator 40, and an ADC 42. The filter 38 includes an electronic circuit system such as a bandpass filter (BPF) configured to allow frequency components of the broadband electronic signal having a frequency value substantially equal to the carrier frequency to pass through. Therefore, the filter 38 filters out any frequencies other than the carrier frequency. For example, refer to... Figure 7 The first filter 38 (BPF1) allows a first frequency band centered at carrier frequency F1 to pass through and filters out frequency components located outside the first frequency band; the second filter 38 (BPF2) allows a second frequency band centered at carrier frequency F2 to pass through and filters out frequency components located outside the second frequency band; the third filter 38 (BPF3) allows a third frequency band centered at carrier frequency F3 to pass through and filters out frequency components located outside the third frequency band, and so on. Each filter 38 receives a broadband electronic signal and outputs a filtered electronic signal including a carrier frequency component associated with a frequency selected according to the bandpass filter frequency. The filtered electronic signal is an optical signal that has been modified, influenced, or otherwise impacted by traveling through human tissue and interacting with blood vessels, and has an applicable carrier frequency. In other words, the filter 38 of the first PPG processor circuit 36 ​​outputs a first filtered electronic signal including a first carrier frequency component modified by human tissue, the filter 38 of the second PPG processor circuit 36 ​​outputs a second filtered electronic signal including a second carrier frequency component modified by human tissue, the filter 38 of the third PPG processor circuit 36 ​​outputs a third filtered electronic signal including a third carrier frequency component modified by human tissue, and so on.

[0059] Demodulator 40 includes an electronic circuitry system, such as an envelope detector, comprising rectification and filtering, configured to extract the amplitude of the carrier frequency component from the filtered electronic signal, leaving an electronic signal without a carrier frequency, while retaining the influence of human tissue on the optical signal. Each demodulator 40 receives one of the filtered electronic signals and outputs one of a plurality of PPG electrical signals in analog form, including the influence of human tissue on the optical signal traveling along a specific signal path. For example, the first demodulator 40 receives a first filtered electronic signal and outputs a first (analog) PPG electronic signal, which includes the influence of human tissue on the first optical signal traveling along the signal path between the first optical transmitter 28 and the first optical receiver 30. Similarly, the second demodulator 40 receives a second filtered electrical signal and outputs a second PPG electrical signal, which includes the influence of human tissue on the second optical signal traveling along the signal path between the second optical transmitter 28 and the second optical receiver 30.

[0060] ADC 42 includes one or more known ADC implementations. ADC 42 receives PPG electronic signals, samples them, and outputs PPG electronic signals as a digital data value stream representing the PPG waveform.

[0061] In embodiments, processor 26 may execute, process, or run instructions to perform the functions described herein for receiver processor circuitry 36. For example, processor 26 may receive broadband electronic signals from optical receiver 30 or receive multiplexer 34 and, using an internal or external ADC 42, convert the analog electronic signals output from multiple optical receivers 30 into digital data values ​​or a stream of digital data values ​​of the electronic signals. Once processor 26 generates the digital optical signal, it may implement a bandpass filter (BPF) as a software process and / or configurable logic hardware, configured to allow frequency components of the broadband electronic signal having a frequency value substantially equal to the carrier frequency to pass through. Additionally, processor 26 may demodulate the filtered data by removing the carrier frequency component using a software process and / or configurable logic hardware (leaving filtered data without the carrier frequency component while retaining the influence of human tissue on the optical signal). Specifically, processor 26 may receive the filtered electronic signal and output a PPG electrical signal in digital form, including the influence of human tissue on the optical signal traveling along a specific signal path.

[0062] Refer again Figure 6A and Figure 6B The wearable electronic device can be configured to operate as follows: Each modulator 32 outputs a modulated electronic signal having a carrier frequency selected by a processor 26, which outputs a program control signal to each modulator 32 to select the carrier frequency. The modulated electronic signal may have a current modulated to an amplitude corresponding to the selected carrier frequency, although the voltage or other electrical characteristics of the modulated electronic signal may also be modulated by the modulator 32. In an exemplary embodiment, the first modulator 32 outputs a first modulated electronic signal having a first carrier frequency F1, and the second modulator 32 outputs a second modulated electronic signal having a second carrier frequency F2. Although for illustrative purposes, Figure 6A Only two modulators 32 are illustrated, but it should be understood that additional modulators 32 may be used. In some embodiments, modulators 32 may include circuitry that multiplies or otherwise modulates the modulated electronic signal to generate multiple modulated electronic signals for multiple optical transmitters 28. All modulators 32 may output modulated electronic signals simultaneously and continuously.

[0063] In some embodiments, the transmit multiplexer 34 is electrically coupled to the modulator 32 and the optical transmitter 28. In such embodiments, the transmit multiplexer 34 receives each of the modulated electronic signals and selectively routes the modulated electronic signals from any of the input ports to any of the output ports based on program control signals. In the exemplary embodiment shown in the figures, a first modulated electronic signal received at a first input port is routed to a first output port, and a second modulated electronic signal received at a second input port is routed to a second output port. In other embodiments, without the transmit multiplexer 34, the modulator 32 is electrically coupled to the optical transmitter 28. In such embodiments, the optical transmitter 28 receives the modulated electronic signals output by the modulator 32 from the modulator 32.

[0064] Each optical transmitter 28 is positioned on the bottom wall and receives a selected modulated electronic signal either from a transmit multiplexer 34 connected to its output port or directly from a modulator 32. Each optical transmitter 28 outputs an optical signal having a modulated light intensity corresponding to the carrier frequency of the modulated electronic signal. The optical signal output by each optical transmitter 28 is based on the modulated electronic signal output by the corresponding modulator 32 and has the carrier frequency of the modulated electronic signal.

[0065] In an exemplary embodiment, a first optical transmitter 28 is connected to a first output port of a transmit multiplexer 34 and thus receives a first modulated electronic signal. Therefore, the first optical transmitter 28 transmits a first optical signal having a first carrier frequency F1 output by the first modulator 32. Similarly, a second optical transmitter 28 is connected to a second output port of a transmit multiplexer 34 and thus receives a second modulated electronic signal output by the second modulator 32. Therefore, the second optical transmitter 28 transmits a second optical signal having a second carrier frequency F2. Although for illustrative purposes, Figure 6A Only two light emitters 28 and two modulators 32 are depicted herein, but it should be understood that the electronic wearable device 10 may include a plurality of individual light emitters 28 or a plurality of light emitters included in an array of light emitters comprising multiple light emitters 28 that output light signals from a common location on the bottom wall of the electronic wearable device 10. The emitter array may form a plurality of light emitters 28, some of which output (emit) light with wavelengths different from the light output (emitted) by the other light emitters 28. For example, in an embodiment, the electronic wearable device 10 may include six light emitter arrays, each comprising four light emitters 28, resulting in more than twenty-four light emitters 28 outputting light signals from six locations on the bottom wall of the electronic wearable device 10. Other combinations of the number of light emitters 28 in each light emitter array are contemplated herein.

[0066] The first and second optical signals output by the first and second optical transmitters 28, respectively, travel through the user's skin (human tissue) and interact with blood vessels. The optical signals are thus modified, influenced, or otherwise impacted by the amount or flow of blood in the signal path or other characteristics of the blood vessels. Typically, the optical signals output by the optical transmitters consist of different sinusoidal carrier frequencies before entering the user's skin. As the optical signal passes through the user's skin, such as the upper layer of skin on the user's wrist, the presence of red blood cells and other objects in the blood vessels through which the light signal passes causes the amplitude of the carrier signal to attenuate. This results in a reduction in the amplitude of the modulated optical signal as the pulse wave of the blood passes through the user's wrist (in the signal path of the optical signal, the pulse wave passes instantaneously directly below the wrist-worn device).

[0067] The light signal passing through the user's skin is received by a first light receiver 30 and a second light receiver 30, each of which is positioned on the bottom wall of the electronic wearable device 10. As each light signal output by the light emitter 28 travels from each light emitter 28 through the user's skin to each light receiver 30, the light signal retains a carrier frequency associated with a modulated electronic signal output by the corresponding modulator 32. In some embodiments, each light receiver 30 acts as a signal mixer because each light receiver 30 receives multiple light signals, each having a predetermined carrier frequency, but outputs only a single broadband electronic signal comprising all the light signals and their corresponding frequency components. In an exemplary embodiment, the first light receiver 30 and the second light receiver 30 receive a first light signal and a second light signal, and each outputs a broadband electronic signal corresponding to the first light signal and the second light signal, and their respective carrier frequencies (that is, the first light signal remains associated with a first carrier frequency F1 and the second light signal remains associated with a second carrier frequency F2). The first light receiver 30 outputs a first broadband electronic signal, and the second light receiver 30 outputs a second broadband electronic signal. Excluding the factor of the different carrier frequencies associated with the first and second optical signals, the first and second broadband electronic signals each have different waveform characteristics because the first optical signal travels along different paths from each optical transmitter 28 to each optical receiver 30. For example, the first optical signal travels from the first optical transmitter 28 to the first optical receiver 30 along a first signal path, the first optical signal travels from the first optical transmitter 28 to the second optical receiver 30 along a second signal path, the second optical signal travels from the second optical transmitter 28 to the first optical receiver 30 along a third signal path, and the second optical signal travels from the second optical transmitter 28 to the second optical receiver 30 along a fourth signal path. As each optical signal passes through the user's skin (human tissue) and / or is reflected from it, the optical signal is modified, influenced, or otherwise impacted by the amount or flow of blood or other characteristics of blood vessels in the signal path of the optical signal, and each optical signal retains this form as it passes from the user's skin to each optical receiver 30.

[0068] In one embodiment, a receive multiplexer 34 electrically couples an optical receiver 30 to a receive processor circuit 36. In such an embodiment, the receive multiplexer 34 receives each of the broadband electronic signals and selectively routes the broadband electronic signals from any of the input ports to any of the output ports based on program control signals received from the processor 26. In the exemplary embodiment shown in the figures, a first broadband electronic signal received at a first input port is routed to a first output port, and a second broadband electronic signal received at a second input port is routed to a second output port. In other embodiments, each optical receiver 30 outputs the broadband electronic signal received by the receive processor circuit 36 ​​and / or the processor 26.

[0069] In an embodiment, the filter 38 of each receiver processor circuit 36 ​​receives a selected broadband electronic signal from a receiver multiplexer 34 connected to its output port, and outputs a filtered electronic signal that retains one of the carrier frequencies of the effect of traveling across the user's skin and the light signal. That is, each filter 38 allows a portion of the selected broadband electronic signal corresponding to the selected carrier frequency to pass through, and filters out portions of the selected broadband electronic signal corresponding to other carrier frequencies. Additionally, the filtered electronic signal may have varying voltage or varying current. In an exemplary embodiment, the filter 38 of the first receiver processor circuit 36 ​​receives a first broadband electronic signal, allows a first carrier frequency F1 to pass through, and outputs a first filtered electronic signal having a portion of the selected broadband electronic signal corresponding to the first carrier frequency F1. Similarly, the filter 38 of the second receiver processor circuit 36 ​​receives a second broadband electronic signal, allows a second carrier frequency F2 to pass through, and outputs a second filtered electronic signal having a portion of the selected broadband electronic signal corresponding to the second carrier frequency F2.

[0070] Each receiver processor circuit 36's demodulator 40 receives a filtered electronic signal, extracts the amplitude of the carrier frequency component (leaving behind the optical signal without a carrier frequency while retaining the effect on the waveform traveling across the user's skin), and outputs a PPG electronic signal in analog form. The PPG electronic signal may have varying voltage or varying current. In an exemplary embodiment, the demodulator 40 of the first receiver processor circuit 36 ​​receives a first filtered electronic signal, extracts the amplitude of the first carrier frequency F1, and outputs a first PPG electronic signal in analog form. Similarly, the demodulator 40 of the second receiver processor circuit 36 ​​receives a second filtered electronic signal, extracts the amplitude of the second carrier frequency F2, and outputs a second PPG electronic signal in analog form. Given that the optical signal (from which the PPG electronic signal is derived) travels along different paths from each optical transmitter 28 to each optical receiver 30, each PPG electronic signal has different waveform characteristics.

[0071] Each receiver processor circuit 36's ADC 42 receives an analog PPG electronic signal, performs analog-to-digital conversion, and outputs a digital PPG electronic signal as a digital data value stream. In an exemplary embodiment, the first ADC 42 receives an analog first PPG electronic signal and outputs a digital first PPG electronic signal. Similarly, the second ADC 42 receives an analog second PPG electronic signal and outputs a digital second PPG electronic signal. The digital data value of each PPG electronic signal is transmitted to the processor 26, which uses the PPG electronic signal to determine physiological information about the user, such as measuring the user's pulse or heart rate, pulse oxygen saturation level (oxygen saturation or SpO2), estimated stress level, maximum oxygen consumption rate (VO2 max), and other parameters.

[0072] In other embodiments, processor 26 may execute, process, or run instructions, code, or software to perform functions described above for each receiver processor circuit 36, such as using an internal or external analog-to-digital converter (ADC) to convert analog optical signals output by multiple optical receivers 30 into digital data values ​​or digital data streams of optical signals. For example, electronic wearable device 10 may include an ADC 42 and processor 26, the ADC being configured to receive analog broadband electronic signals output by optical receivers 30 and output the broadband electronic signals as a digital data stream corresponding to the broadband electronic signals, the processor filtering the broadband electronic signals and demodulating the filtered optical signals to output PPG electronic signals, the PPG electronic signals including characteristics imparted to the optical signals due to travel across the user's skin. Similarly, processor 26 may include an ADC 42 configured to receive analog broadband electronic signals output by optical receivers 30 and output broadband electronic signals as a digital data stream corresponding to the broadband electronic signals.

[0073] In an embodiment, after demodulating the broadband electronic signal or the filtered digital broadband electronic signal, the processor 26 identifies and the memory element 24 can store the location and wavelength of the optical signal output by each optical transmitter 28 for each PPG signal, each PPG signal being generated from the broadband electronic signal output by each optical receiver 30. For example, in an embodiment where the optical transmitter 28 uses six different carrier frequencies, the processor 26 identifies and the memory element 24 can store one of the six carrier frequencies within the broadband electronic signal or the filtered digital broadband electronic signal, separate the sub-component signals based on the identified carrier frequencies, demodulate the PPG signals from the carrier signals, and evaluate the PPG signals to determine the user's cardiac information based on the identification of the optical transmitter 28 from which the optical signal originates, the location of the optical transmitter 28, the wavelength of the optical signal emitted by the optical transmitter 28, and the signal path along which the optical signal travels from the optical transmitter 28 to the optical receiver 30.

[0074] Reference Figure 8In various embodiments, the electronic wearable device 10 includes a plurality of light emitters 28 (TX), each of which emits an optical signal having one of a plurality of (optical) wavelengths (λ). The use of multiple light emitters 28, each emitting at a different wavelength, enables the processor 26 of the electronic wearable device 10 to perform pulse spectroscopy to determine cardiac information, including pulse oxygen saturation. To distinguish one optical signal from another, the light emitters 28 still receive modulated electronic signals and modulate the optical signals with a predetermined carrier frequency. Therefore, the electronic wearable device 10 also includes a modulator 32 for each light emitter 28, along with a transmit multiplexer 34 or circuitry for multiplying or otherwise modifying the modulated electronic signals to generate additional modulated electronic signals for each light emitter 28. Each modulator 32 outputs a modulated electronic signal having one of a plurality of carrier frequencies, and the multiplexer 34 uses program control signals to route each modulated electronic signal to the light emitter 28 selected by the processor 26. In an exemplary embodiment, a first light emitter 28 outputs (emits) a first optical signal having a first wavelength λ1 and a first carrier frequency F1, a second light emitter 28 outputs a second optical signal having a second wavelength λ2 and a second carrier frequency F2, and so on for a third, fourth, and fifth light emitter 28. The five light emitters 28 can output (emit) optical signals of specific wavelengths to perform pulse spectroscopy measurements. Exemplary wavelengths include approximately 540 nanometers (nm), approximately 630 nm, approximately 660 nm, approximately 700 nm, and approximately 940 nm. The light emitters 28 can be formed within a light emitter array, or otherwise grouped at a common location on the bottom wall of the electronic wearable device 10, the light emitter array including multiple light emitters 28 outputting optical signals from the common location on the bottom wall of the electronic wearable device 10. The electronic wearable device 10 may include multiple optical transmitter arrays, each containing multiple optical transmitters 28 that output (transmit) optical signals having a predetermined carrier frequency and wavelengths different from those of the other optical transmitters 28 in the array. The optical transmitters 28 may be positioned relative to the optical receiver 30 in virtually any form and in virtually any location.

[0075] The light signal emitted by the light emitter 28, passing through and / or reflected by the user's skin, is received by at least one light receiver 30, which outputs a broadband electronic signal. This broadband electronic signal is received by five receiver processor circuits 36 via a receiver multiplexer 34 (e.g., ...). Figure 8 (as shown), or received by processor 26 via analog-to-digital converter 42 for filtering and demodulation. Each receiver processor circuit 36 ​​or processor 26 outputs the PPG electronic signal in the same manner as described above.

[0076] In an embodiment, such as Figure 9A As shown in Figure 9F, the electronic wearable device 10 includes a plurality of light emitters 28 and a plurality of light receivers 30, wherein each light emitter 28 outputs (transmits) an optical signal having one of a plurality of carrier frequencies and a plurality of (optical) wavelengths (λ). The plurality of light emitters 28 and the plurality of light receivers 30 can be arranged on the bottom wall of the electronic wearable device 10 such that the optical signals output by the plurality of light emitters 28 can travel to the light receivers 30 along different signal paths. The plurality of light emitters 28 can be positioned at a substantially common location on the bottom wall of the electronic wearable device 10. For example, an array of light emitters may include a plurality of light emitters 28.

[0077] Each optical emitter array may include multiple optical emitters 28. For example... Figure 9B As shown, the optical transmitter array may include four optical transmitters 28 arranged in a two-dimensional configuration and positioned relative to each other. The optical signals output from these four optical transmitters 28 will travel along substantially the same signal path to the optical receiver 30. For example, as Figure 9A As shown, the optical signal output by the optical transmitter 28 in the first optical transmitter array TXA1(A) travels along the signal path P1A-1 to the first optical receiver (RX1). Similarly, the optical signal output by the optical transmitter 28 in the second optical transmitter array TXA2(A) travels along the signal path P2A-1 to the second optical receiver (RX2).

[0078] It should be understood that many arrangements of optical transmitter 28 and optical receiver 30 are conceived, and processor 26 can select a carrier frequency for each optical signal output by optical transmitter 28, the carrier frequency of which enables processor 26 to determine the optical transmitter 28 from which each optical signal received by optical transmitter 30 originates and the signal path of each optical signal along its journey to optical receiver 30, which outputs a broadband electronic signal.

[0079] In some embodiments, such as Figure 9D As shown, each signal path between the light transmitter 28 and each light receiver 30 is associated with a different (unique) carrier frequency. In such an embodiment, each optical signal with a different (unique) carrier frequency enables the processor 26 to control the light transmitter 28 to simultaneously transmit optical signals in a common area (zone) of the user's skin, because the processor 26 can be configured to determine the light transmitter 28 from which each optical signal received by the light transmitter 30 originates and the signal path along which the optical signal travels to the light receiver 30.

[0080] In other embodiments, the processor 26 may control the modulator 32 and the light emitter to utilize fewer modulated electronic signals, each having a (unique) carrier frequency different from that of the plurality of light emitters 28. For example, in one embodiment, the processor 26 may divide the plurality of light emitters 28 on the bottom wall of the electronic wearable device 10 into multiple regions and control the modulator 32 and the light emitter such that all light signals traveling or originating in one region utilize or are associated with a carrier frequency different from or with other light signals traveling or originating in that region. For example, the bottom wall of the electronic wearable device 10 may be divided into three regions, and the processor 26 may control the modulator 32 and the light emitter such that all light signals traveling or originating in a first region are associated with a carrier frequency different from that of other light signals traveling or originating in the first region, all light signals traveling or originating in a second region are associated with a carrier frequency different from that of other light signals traveling or originating in the second region, and all light signals traveling or originating in a third region are associated with a carrier frequency different from that of other light signals traveling or originating in the third region. At any given time, one or more optical transmitters 28 in one region can output an optical signal with the same carrier frequency as one or more optical transmitters 28 in the other two regions.

[0081] In other embodiments, the processor 26 may control the optical transmitter 28 to output optical signals during a repetitive period of optical signal transmission by dividing a periodic time interval into transmission periods for a plurality of optical transmitters 28, each of which is assigned one of a plurality of predetermined transmission periods, and all optical signals output within a given transmission period may be associated with a carrier frequency different from other optical signals output during that transmission period. For example, an optical signal transmission cycle performed by a plurality of optical transmitters within a 300-microsecond periodic time interval may be divided into three transmission periods of 100 microseconds each, and all optical signals output by the optical transmitter 28 in a first periodic time interval (from the beginning of each periodic time interval to 100 microseconds) may be associated with a carrier frequency different from other optical signals output during that first periodic time interval, all optical signals output by the optical transmitter 28 in a second periodic time interval (100 microseconds to 200 microseconds) may be associated with a carrier frequency different from other optical signals output during that second periodic time interval, and all optical signals output by the optical transmitter 28 in a third periodic time interval (200 microseconds to 300 microseconds) may be associated with a carrier frequency different from other optical signals output during that third periodic time interval. For any given time period, one or more optical transmitters 28 can output an optical signal with the same carrier frequency as one or more optical transmitters 28 in the other two time periods.

[0082] return Figure 9A The bottom wall of the electronic wearable device 10 includes multiple optical receivers 28 (RX1 to RXn), multiple optical emitter arrays TXA1(A) to TXAn(A), and multiple optical emitter arrays TXA1(B) to TXAn(B). The multiple optical emitter arrays TXA1(A) to TXAn(A) are separated from the adjacent optical receivers 28 (RX1 to RXn) by a first distance, and the multiple optical emitter arrays TXA1(B) to TXAn(B) are separated from the optical receivers 28 (RX1 to RXn) by a second distance, the second distance being shorter than the first distance. Figure 9A In the configuration shown, multiple optical receivers 28 (RX1 to RXn) are closer to one of the multiple optical transmitter arrays TXA1(A) to TXAn(A) than multiple optical transmitter arrays TXA1(B) to TXAn(B).

[0083] like Figure 9B As shown, each optical transmitter array may include multiple optical transmitters 28 located at a substantially common position on the bottom wall of the electronic wearable device 10, and each optical transmitter 28 outputs an optical signal associated with a predetermined carrier frequency that travels along a signal path to the optical receiver 30. For example, the optical transmitter array may include four optical transmitters 28, each outputting an optical signal associated with a predetermined carrier frequency (f1 to f4) and a predetermined wavelength (λ). Figure 9D As shown, the position of each optical emitter 28 within the optical emitter array can be specified using (x, y) coordinates, where the four optical emitters 28 in the optical emitter array TXA1(A) are specified to be located at... Figure 9B One of the four positions depicted. Specifically, the first optical emitter 28 in the optical emitter array TXA1(A) can be located at the lower left position (0, 0), having a predetermined carrier frequency (ƒ1) and a predetermined wavelength (λ) that is visually perceived as red between 610 nm and 640 nm. Similarly, the second optical emitter 28 in the optical emitter array TXA1(A) can be located at the lower right position (0, 1), having a predetermined carrier frequency (ƒ2) and a predetermined wavelength (λ) that is visually perceived as red between 640 nm and 670 nm. Similarly, the third optical emitter 28 in the optical emitter array TXA1(A) can be located at the upper left position (1, 0), having a predetermined carrier frequency (ƒ3) and a predetermined wavelength (λ) that is visually perceived as red between 670 nm and 720 nm. Similarly, the fourth optical emitter 28 in the optical emitter array TXA1(A) can be located at the upper right position (1, 1), having a predetermined carrier frequency (ƒ4) and a predetermined wavelength (λ) in the infrared band between 920 nm and 950 nm. In an embodiment, Figure 9AThe light emitter array presented in the image can be composed of or replaced by a single light emitter 28, which can be positioned at the center where the light emitter array would otherwise be located. For example, in... Figure 9D In the embodiments described, the optical emitter array TXA1(B) may consist of a single optical emitter 28 that outputs an optical signal having a predetermined carrier frequency (ƒ5) and a predetermined wavelength (λ) perceived visually as green between 520 nm and 550 nm. Figure 9D The location, carrier frequency and wavelength of each optical transmitter 28 in the optical transmitter arrays TXA1(A) and TXA1(B) are provided, as well as two signals to the nearby optical receivers 30 (RX1 and RX2).

[0084] Similarly, in the embodiments, each has a different frequency (ƒ6 to ƒ6). 10 Five additional carrier signals will be associated with optical emitters 28 within optical emitter arrays TXA2(A) and TXA2(B). Specifically, the first optical emitter 28 in optical emitter array TXA2(A) can be located at the lower left position (0, 0), having a predetermined carrier frequency (ƒ6) and a predetermined wavelength (λ) that is visually perceived as red between 610 nm and 640 nm. Similarly, the second optical emitter 28 in optical emitter array TXA2(A) can be located at the lower right position (0, 1), having a predetermined carrier frequency (ƒ7) and a predetermined wavelength (λ) that is visually perceived as red between 640 nm and 670 nm. Similarly, the third optical emitter 28 in optical emitter array TXA2(A) can be located at the upper left position (1, 0), having a predetermined carrier frequency (ƒ8) and a predetermined wavelength (λ) that is visually perceived as red between 670 nm and 720 nm. Similarly, the fourth optical emitter 28 in the optical emitter array TXA2(A) can be located at the upper right position (1, 1), having a predetermined carrier frequency (ƒ9) and a predetermined wavelength (λ) in the infrared band between 920 nm and 950 nm. The optical emitter array TXA2(B) can consist of a single optical emitter 28, which outputs a wavelength with a predetermined carrier frequency (ƒ9). 10 ( ) and a light signal with a predetermined wavelength (λ) between 520 nm and 550 nm that is visually perceived as green.

[0085] Extend this configuration to Figure 9A Other light emitter arrays depicted in the figure, in embodiments, each have different frequencies (ƒ n To ƒ n+4The additional five carrier signals will be associated with optical transmitters 28 within optical transmitters TXA2(A) and TXA2(B). Specifically, the first optical transmitter 28 in the optical transmitter array TXAn(A) can be located at the lower left position (0, 0) and has a predetermined carrier frequency (ƒ). n The predetermined wavelength (λ) between 610 nm and 640 nm, which is visually perceived as red. Similarly, the second optical emitter 28 in the optical emitter array TXAn(A) can be located at the lower right position (0, 1) with a predetermined carrier frequency (ƒ). n+1 The predetermined wavelength (λ) between 640 nm and 670 nm, which is visually perceived as red. Similarly, the third optical emitter 28 in the optical emitter array TXAn(A) can be located at the upper left position (1, 0) with a predetermined carrier frequency (ƒ). n+2 The predetermined wavelength (λ) between 670 nm and 720 nm, which is visually perceived as red. Similarly, the fourth optical emitter 28 in the optical emitter array TXAn(A) can be located at the upper right position (1, 1) with a predetermined carrier frequency (ƒ). n+3 The optical emitter array TXAn(B) can consist of a single optical emitter 28, which outputs a predetermined wavelength (λ) between 920 nm and 950 nm in the infrared band. n+4 ( ) and a light signal with a predetermined wavelength (λ) between 520 nm and 550 nm that is visually perceived as green.

[0086] It should be understood that each modulator 32 may include circuitry such as signal multipliers and signal dividers to generate each of the modulated electronic signals having different frequencies.

[0087] like Figure 9A As shown, the optical signals output by each optical transmitter 28 in the optical transmitter array TXA1(A) are transmitted to the nearest optical receiver 30 along a common signal path, such as along signal path P1A-1 to the first optical receiver 30 (RX1), along signal path P1A-2 to the second optical receiver 30 (RX2), and along signal path P1A-n to the nearest optical receiver 30 (RXn).

[0088] Processor 26 can cause multiple light emitters 28 to output light signals with specific wavelengths to determine physiological information about the user. For example, it is generally understood that the absorption of light signals by the blood of a typical user varies according to the wavelength of the light signal, and that there are differences in light signal absorption between oxygenated and deoxygenated blood. Figure 9CThe diagram shows a graph of the absorption coefficient versus the wavelength of the optical signal, illustrating the variability of absorption with respect to wavelength and the absorption difference between oxygenated and deoxygenated blood. Compared to PPG signals generated from optical signals with other wavelengths, using a wavelength with the absorption coefficient maximized by oxygenated blood for the optical signal yields a PPG signal with an improved signal-to-noise ratio for the cardiac component, resulting in accurate heart rate determination. In an embodiment, processor 26 can output from each of a plurality of optical emitters 28. Figure 9C The processor 26 uses a light signal at a wavelength of a portion of the spectrum labeled "heart rate" to generate a PPG signal, which is then used by a light receiver to determine the user's heart rate. The processor 26 is configured to use the wavelengths of two (or three in any embodiment) light signals that generate at least two PPG signals to determine the user's pulse oxygen saturation. To distinguish between a response to the light signal due to oxygenated blood and a response due to deoxygenated blood, the processor 26 can cause the light emitter 28 to... Figure 9C In the graph, light signals of two wavelengths are output in regions where there is a significant separation between the absorption coefficients of oxygenated and deoxygenated blood. For example, processor 26 can cause multiple light emitters 28 to output light signals at wavelengths (λ) where the separation between the absorption coefficients of oxygenated and deoxygenated blood in the red wavelengths of the visible spectrum (TX1, TX2, and TX3) and the lower infrared wavelength (TX4) is sufficient for processor 26 to determine pulse oxygenation and other physiological information about the user.

[0089] For example, in one embodiment, a plurality of light emitter arrays TXA1(A) to TXAn(A) positioned on the bottom wall of the electronic wearable device 10 can output light signals of wavelengths that enable the processor 26 to determine information about the user's physiological state. For example, in Figure 9CIn the embodiment shown, the optical transmitter arrays TXA1(B) to TXAn(B) may each include or be composed of an optical transmitter 28 that outputs optical signals having a predetermined carrier frequency (ƒ5) and a wavelength (λ) between 520 nm and 550 nm. These optical signals are received by an optical receiver 30, which serves as one of a plurality of optical signals in a broadband electronic signal that the processor 26 can isolate and use to determine the user's heart rate. Similarly, the optical transmitter arrays TXA1(A) to TXAn(A) may each include a first optical transmitter 28, a second optical transmitter 28, a third optical transmitter 28, and a fourth optical transmitter 28. The first optical transmitter outputs an optical signal with a predetermined carrier frequency (ƒ1) and a wavelength (λ) between 610 nm and 640 nm. The second optical transmitter outputs an optical signal with a predetermined carrier frequency (ƒ2) and a wavelength (λ) between 640 nm and 670 nm. The third optical transmitter outputs an optical signal with a predetermined carrier frequency (ƒ3) and a wavelength (λ) between 690 nm and 720 nm. The fourth optical transmitter outputs an optical signal with a predetermined carrier frequency (ƒ4) and a wavelength (λ) between 920 nm and 950 nm. These optical signals are all received by the optical receiver 30 as one of a plurality of optical signals in a broadband electronic signal and are used by the processor 26 to determine physiological information such as the user's pulse oxygen content level (also known as blood oxygen saturation or SpO2 level), estimated stress level, maximum oxygen consumption rate (VO2 max), etc.

[0090] The technology disclosed herein enables processor 26 to determine the source of the light signal and the signal path of the light signal through the user's skin from light emitter 28 to light receiver 30 for each PPG signal, and to select one or more PPG signals based on the determined signal path and signal-to-noise ratio to determine the user's physiological information. Figure 9A As shown, the first PPG signal can be associated with the optical signal transmitted along the signal path "P1A-1" from the optical transmitter 28 of the optical transmitter array TXA1(A) to the first optical receiver 28 (RX1), and the second PPG signal can be associated with the optical signal transmitted along the signal path "P1B-1" from the optical transmitter 28 of the optical transmitter array TXA1(B) to the first optical receiver 28 (RX1). Similarly, the third PPG signal can be associated with the optical signal transmitted along the signal path "P2A-2" from the optical transmitter 28 of the optical transmitter array TXA2(A) to the second optical receiver 28 (RX2), and the fourth PPG signal can be associated with the optical signal transmitted along the signal path "P2B-2" from the optical transmitter 28 of the optical transmitter array TXA2(B) to the second optical receiver 28 (RX2).

[0091] It should be understood that each optical signal output into and reflected from the user's skin can be received by any optical receiver 30 sufficiently close to the optical transmitter 28 of the output optical signal. For example, exemplary signal paths “P1A-2” and “P2A-1” are shown for optical signals transmitted from the optical transmitter 28 in optical transmitter TXA1(A) to the second optical receiver 30 (RX2) and from the optical transmitter 28 in optical transmitter TXA2(A) to the first optical receiver 30 (RX1), respectively. As the optical signals output by the optical transmitter 28 in optical transmitter array TXA1(A) and optical transmitter 28 in optical transmitter array TXA2(A) travel within signal paths “P1A-2” and “P2-1”, respectively, both the first optical receiver (RX1) and the second optical receiver (RX2) will simultaneously receive those optical signals from the user's skin within the broadband electronic signal, and the resulting PPG signal for use by processor 26 will correspond in time. Similarly, exemplary signal paths “P1B-2” and “P2B-1” are shown for the optical signals transmitted from the optical transmitter 28 in the optical transmitter array TXA1(B) to the second optical receiver 30 (RX2) and from the optical transmitter array TXA2(B) to the first optical receiver 30 (RX1), respectively. As the optical signals output by the optical transmitter 28 in the optical transmitter array TXA1(B) and the optical transmitter 28 in the optical transmitter array TXA2(B) travel within signal paths “P1B-2” and “P2B-1”, respectively, both the first optical receiver (RX1) and the second optical receiver (RX2) will simultaneously receive those optical signals from the user's skin within the broadband electronic signal, and the resulting PPG signal for use by the processor 26 will correspond in time.

[0092] It should be understood that similar arrangements of optical components may exist, and therefore additional signal paths are illustrated for “N” such groups of optical components. In other words, an additional PPG signal will also be associated with an optical signal transmitted along a signal path “PnA-n” extending from the optical transmitter 28 in the optical transmitter array TXAn(A) corresponding to the position and wavelength of the transmitter array to the adjacent optical receiver 28 (RXn), and another PPG signal will also be associated with an optical signal transmitted along a signal path “PnB-n” extending from the optical transmitter 28 in the optical transmitter array TXAn(B) to the adjacent optical receiver 28 (RXn). Exemplary signal paths “PnA-1” and “PnB-1” are shown for the optical signal transmitted from the optical transmitter 28 in the optical transmitter TXAn(A) to the first optical receiver 30 (RX1) and from the optical transmitter TXAn(B) to the first optical receiver 30 (RX1), respectively. As the optical signals output by optical transmitters 28 in optical transmitter array TXAn(A) and optical transmitters 28 in optical transmitter array TXAn(B) travel within signal paths “PnA-1” and “PnB-1” respectively, the first optical receiver (RX1) will simultaneously receive those optical signals from the user's skin within the broadband electronic signal, and the resulting PPG signal used by processor 26 will correspond in time. Similarly, exemplary signal paths “PnA-2” and “PnB-2” are shown for the optical signals transmitted from optical transmitters 28 in optical transmitter TXAn(A) to the second optical receiver 30 (RX2) and from TXAn(B) to the second optical receiver 30 (RX2), respectively. As the optical signals output by optical transmitters 28 in optical transmitter arrays TXAn(A) and TXAn(B) travel within signal paths “PnA-2” and “PnB-2” respectively, the second optical receiver (RX2) will simultaneously receive those optical signals from the user's skin within the broadband electronic signal, and the resulting PPG signal for use by processor 26 will correspond in time. Similarly, exemplary signal paths “P1A-n”, “P2A-n”, “P1B-n”, and “P2B-n” are shown for the optical signals transmitted from optical transmitters 28 in optical transmitters TXA1(A), TXA2(A), TXA1(B), and TXA2(B) to optical receiver 28 (RXn). As the optical signals output by the optical transmitters 28 in the optical transmitter arrays TXA1(A), TXA2(A), TXA1(B) and TXA2(B) travel within the signal paths “P1A-n”, “P2A-n”, “P1B-n” and “P2B-n” respectively, the optical receiver 28 (RXn) will simultaneously receive those optical signals from the user’s skin within the broadband electronic signal, and the resulting PPG signal available for use by the processor 26 will correspond in time.

[0093] Since the optical receiver 28 can receive optical signals simultaneously output by optical transmitters 28 at different locations, the multiplexing of the optical signals emitted by the optical transmitters 28 enables the processor 26 to determine and sample the different signal paths that each optical signal travels from different optical transmitters 28 to the optical receiver 30. For example, the processor 26 can determine physiological information by selecting one or more of the signal paths "P1A-1" (associated with optical transmitter TXA1(A)), "P1B-1" (associated with optical transmitter TXA1(B)), and "P2A-1" (associated with optical transmitter TXA2(A)) using the PPG signal associated with the optical signal output by the first optical receiver (RX1).

[0094] Similar to the exemplary wavelengths and five carrier frequencies (ƒ1 to ƒ5) of the optical emitter 28 in optical emitter arrays TXA1(A) and TXA1(B), each has a different frequency (ƒ6 to ƒ7). 10 The five additional carrier signals are associated with optical transmitters 28 in optical transmitter arrays TXA2(A) and TXA2(B). By extension, for a group of N such optical transmitter arrays, each group will utilize its own different frequency (ƒ). n To ƒ n+4 Five or more carrier signals, up to "N" optical transmitter arrays, each of which is associated with a carrier signal of a different frequency.

[0095] In embodiments, processor 26 and / or each receiver processor circuit 36 ​​may execute, process, or run instructions, code, or software to perform Figure 10 The processing steps are shown in the figure. Figure 10 This is a flowchart 100 according to embodiments of the present technology for determining how to filter and demodulate an optical signal received from a user's skin to generate a PPG electronic signal. In various embodiments, one or more regions (or the entire method 100) of method 100 can be implemented by any suitable device. For example, one or more portions of method 100 can be executed by processor 26 in conjunction with one or more receiver processor circuits 36, such as... Figure 6B As shown. Method 100 represents the execution of calculating and displaying physiological information about a user using a broadband electronic signal output by a light receiver 30 based on the reflection of multiple light signals received from the user's skin, each of which has a different carrier frequency. For example, method 100 may represent iterative steps taken to generate a PPG electronic signal by demodulating a filtered digital broadband electronic signal and calculating physiological information about the user, as referenced herein. Figures 6A to 6B The physiological information calculated in this discussion is displayed via display 16.

[0096] Referring to processing step 101, processor 26 receives an analog broadband electronic signal from receive multiplexer 34 (block 101). Receive multiplexer 34 can redirect the analog broadband electronic signal received by receive multiplexer 34 from optical receiver 30. Alternatively, processor 26 can directly receive broadband electronic signals from optical receiver 30; that is, processor 26 can receive a first broadband electronic signal from first optical receiver 30 and a second broadband electronic signal from second optical receiver 30. This may also include, for example, receiving broadband electronic signals from optical receiver 30, as referenced... Figure 6B As discussed. In other embodiments, if an analog-to-digital converter such as ADC 42 is not integrated within processor 26, the broadband electronic signal is received by ADC 42.

[0097] Referring to processing step 102, each broadband electronic signal (in its analog form output by the optical receiver 30 or receiver multiplexer 34) is converted into one of a plurality of broadband digital signals, each comprising a stream of digital data values. That is, a first broadband electronic signal is converted into a first broadband digital signal, and a second broadband electronic signal is converted into a second broadband digital signal. This conversion may include electronic waveform sampling of each broadband electronic signal such that the result of the conversion is that each broadband digital signal comprises a stream of digital data values, where each digital data value represents the voltage or current at the time it was sampled. This conversion may be performed by an analog-to-digital converter integrated within processor 26 or by one or more ADCs 42. Since the digital broadband signal can be generated from the analog broadband signal by an ADC 42 within processor 26 or by an ADC 42 external to processor 26 but controlled by processor 26, processor 26 and / or each receiver processor circuit 36 ​​can convert each broadband electronic signal into one of a plurality of broadband digital signals. After the analog broadband signal is output by the optical receiver 30 or the receiver multiplexer 34, the ADC 42 can receive the analog broadband signal and convert the analog optical signal into digital data values ​​or digital data value streams of the optical signal.

[0098] Referring to processing step 103, each broadband digital signal is filtered using multiple bandpass filters to generate a filtered digital signal, which includes one or more frequency components of the broadband electronic signal having frequency values ​​substantially equal to the carrier frequency. Each bandpass filter can be implemented as a finite impulse response (FIR) filter, an infinite impulse response (IIR) filter, or other DSP process. A continuous bandpass filter can be implemented for each carrier frequency utilized by modulator 32. Furthermore, each bandpass filter allows some portions of the broadband digital signal corresponding to the selected carrier frequency to pass through and filters out some portions of the broadband digital signal corresponding to other carrier frequencies. Each bandpass filter outputs or generates a filtered digital signal for each broadband digital signal it operates on. For example, if more than two optical receivers are used, the first broadband digital signal (converted from the first broadband electronic signal output by the first optical receiver 30) is bandpass filtered multiple times, once per carrier frequency, wherein each bandpass filtering process generates one consecutive filtered digital signal derived from the first broadband signal; the second broadband digital signal is filtered multiple times, once per carrier frequency, wherein each bandpass filtering process generates one consecutive filtered digital signal derived from the second broadband signal, and so on. Therefore, in this embodiment, the processor 26 and / or each receiver processor circuit 36 ​​can receive the broadband electronic signal, perform a bandpass function based on a predetermined carrier frequency, and output a first filtered electronic signal having a first carrier frequency.

[0099] Referring to processing step 104, each filtered digital signal is demodulated to generate and output one of a plurality of consecutive PPG electronic signals. The demodulation process, implemented by processor 26 and / or each receiver processor circuit 36, extracts the amplitude of the carrier frequency component from each filtered digital signal, leaving a digital signal without the carrier frequency while preserving the influence of human tissue on the optical signal. For example, the demodulation process demodulates a first filtered digital signal from a first broadband signal to generate a first PPG electronic signal, demodulates a second filtered digital signal from the first broadband signal to generate a second PPG electronic signal, and so on, thereby demodulating each filtered digital signal from each broadband signal. The demodulated filtered optical signal is a PPG electronic signal, which includes characteristics imparted to the optical signal due to travel through the user's skin.

[0100] Referring to processing step 105, after the amplitude of the carrier frequency has been extracted, processor 26 then uses each of the PPG electronic signals to determine physiological information about the user, such as the user's heart rate, pulse oxygen content level (also known as blood oxygen saturation or SpO2 level), estimated stress level, maximum oxygen consumption rate (VO2 max), etc.

[0101] exist Figure 6A and Figure 6BThe circuit system shown and described above depicts only one configuration for PPG electronic signal processing, in which there are an equal number of modulators 32, optical transmitters 28, optical receivers 30, and receiver processor circuitry 36. In other embodiments, there may be unequal numbers of components. For example, there may be fewer modulators 32 than optical transmitters 28, such that at least one modulator 32 can provide modulated electronic signals (with a specific carrier frequency) to more than one optical transmitter 28. Different numbers of optical transmitters 28 and optical receivers 30, and different numbers of optical receivers 30 and receiver processor circuitry 36, may be present.

[0102] It should be understood that, in the embodiments, the processor 26 may control a plurality of modulators 32 to implement a modulation function that produces an output of a modulated electronic signal having a predetermined frequency, phase and / or waveform, the output of which enables each optical signal and each optical transmitter 28 from which it outputs an optical signal to be distinguished from optical signals output by other optical transmitters 28.

[0103] For example, in one embodiment, processor 26 can control multiple modulators 32 to each output a modulated electrical signal having a phase different from other modulated electrical signals. For instance, processor 26 can control a first modulator 32 to output a first modulated electronic signal with a first signal phase and a second modulated electronic signal with a second signal phase. The first and second modulated electronic signals can have the same frequency and amplitude. Processor 26 can select the first and second signal phases with a 180-degree phase offset, which can be a sufficient phase difference between the two modulated electronic signals to allow processor 26 to reliably identify and accurately separate the optical signals associated with those modulated electronic signals. As another example, processor 26 can control the first modulator 32 to output a first modulated electronic signal with a first signal phase, a second modulated electronic signal with a second signal phase, a third modulated electronic signal with a third signal phase, and a fourth modulated electronic signal with a fourth signal phase. The processor 26 can select the first signal phase, the second signal phase, the third signal phase, and the fourth signal phase with a phase offset of 90 degrees (for example, 0 degrees, 90 degrees, 180 degrees, and 270 degrees for the first signal phase, the second signal phase, the third signal phase, and the fourth signal phase, respectively). This phase offset can be a sufficient phase difference between the four modulated electronic signals, enabling the processor 26 to reliably identify and accurately separate the modulated electronic signals.

[0104] In this embodiment, the processor 26 can control multiple modulators 32 to each output a modulated electronic signal with a waveform different from other modulated electronic signals. For example, the processor 26 can control a first modulator 32 to output a first modulated electronic signal with a first waveform and a second modulated electronic signal with a second waveform. The first and second modulated electronic signals can have the same frequency and amplitude. The processor 26 can select the first and second waveforms, which are sufficiently different to enable the processor 26 to reliably identify and accurately separate the optical signals associated with the modulated electronic signals.

[0105] Throughout this specification, references to "an embodiment," "an embodiment," or "some embodiments" mean that the feature or features being referenced are included in at least one embodiment of the technology. Individual references to "an embodiment," "an embodiment," or "some embodiments" in this description do not necessarily refer to the same embodiment and are not mutually exclusive, unless so stated and / or otherwise readily apparent from the description to those not skilled in the art. For example, features, structures, actions, etc., described in one embodiment may also be included in other embodiments, but not necessarily. Therefore, the technology can include various combinations and / or integrations of the embodiments described herein.

[0106] Although this application sets forth detailed descriptions of numerous different embodiments, it should be understood that the legal scope of the description is defined by the terms of the claims and equivalents set forth at the end of this patent. The detailed descriptions will be construed as merely exemplary and do not describe every possible embodiment, as it would be impractical to describe every possible embodiment. Numerous alternative embodiments can be implemented using techniques developed after the filing date of this patent, which will still fall within the scope of the claims.

[0107] Throughout this specification, multiple instances can implement components, operations, or structures described as single instances. Although individual operations of one or more methods are illustrated and described as separate operations, one or more individual operations can be performed simultaneously, and it is not required that they be performed in the illustrated order. Structures and functions presented as separate components in the example configuration can be implemented as combined structures or components. Similarly, structures and functions presented as single components can be implemented as separate components. These and other variations, modifications, additions, and improvements fall within the scope of the subject matter herein.

[0108] As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” or any other variation thereof are intended to cover non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such a process, method, article, or apparatus.

[0109] The patent claims at the end of this patent application are not intended to be interpreted in accordance with 35 USC §112(f) unless they expressly use conventional device-plus-function language such as “means for…” or “steps for…” as expressly stated in the claims.

[0110] Although the present technology has been described with reference to the embodiments illustrated in the accompanying drawings, it should be noted that equivalents and substitutions may be used herein without departing from the scope of the technology described in the claims.

[0111] Therefore, various embodiments of this technology have been described, and the new content claimed and expected to be protected by a patent certificate includes the following:

Claims

1. An electronic wearable device, comprising: A housing, the housing including a bottom wall configured to contact a user's skin; A first modulator, configured to output a first modulated electronic signal having a first carrier frequency; A second modulator is configured to output a second modulated electronic signal having a second carrier frequency; A first light emitter, coupled to the first modulator, is positioned on the bottom wall and configured to output a first light signal based on the first modulated electronic signal, the first light signal being output into the user's skin and having the first carrier frequency; A second light emitter, coupled to the second modulator, is positioned on the bottom wall and configured to output a second light signal based on the second modulated electronic signal, the second light signal being output into the user's skin and having the second carrier frequency; An optical receiver, positioned on the bottom wall and configured to receive the first optical signal and the second optical signal from the user's skin as a broadband electronic signal, and output the broadband electronic signal, the broadband electronic signal comprising the first optical signal and the second optical signal respectively associated with the first carrier frequency and the second carrier frequency; A first receiving processor circuit is configured to receive the broadband electronic signal including the first optical signal having the first carrier frequency, and to output a first photoplethysmography (PPG) electronic signal corresponding to the first optical signal based on the first carrier frequency. and A second receiver processor circuit is configured to receive the broadband electronic signal including the second optical signal having the second carrier frequency, and to output a second PPG electronic signal corresponding to the second optical signal based on the second carrier frequency.

2. The electronic wearable device according to claim 1, wherein, The broadband electronic signal includes the first carrier frequency and the second carrier frequency as frequency components.

3. The electronic wearable device according to claim 2, wherein, The first receiving processor circuit is electrically coupled to the optical receiver and includes a first filter configured to receive the broadband electronic signal, perform a bandpass function based on the first carrier frequency, and output a first filtered electronic signal having the first carrier frequency.

4. The electronic wearable device according to claim 3, wherein, The first receiving processor circuit includes a first demodulator, which is configured to receive the first filtered electronic signal, extract the amplitude of the first carrier frequency, and output the first PPG electronic signal.

5. The electronic wearable device according to claim 2, wherein, The second receiving processor circuit is electrically coupled to the optical receiver and includes a second bandpass filter configured to receive the broadband electronic signal, perform a bandpass function based on the second carrier frequency, and output a second filtered electronic signal having the second carrier frequency.

6. The electronic wearable device according to claim 5, wherein, The second receiver processor circuit includes a second demodulator configured to receive the second filtered electronic signal, extract the amplitude of the second carrier frequency, and output the second PPG electronic signal.

7. The electronic wearable device according to claim 1, wherein, The first modulator and the second modulator each include a transconductance amplifier, wherein the first light emitter and the second light emitter are each light-emitting diodes (LEDs), and wherein the light receiver is a photodiode.

8. The electronic wearable device according to claim 1, wherein, The first light emitter and the second light emitter are positioned at a first location on the bottom wall, and the light receiver is positioned at a second location on the bottom wall.

9. The electronic wearable device according to claim 1, wherein, The first receiving processor circuit includes a first analog-to-digital converter (ADC) configured to receive the first PPG electronic signal and output the first PPG electronic signal as a digital data value stream representing the PPG waveform, and wherein the second receiving processor circuit includes a second ADC configured to receive the second PPG electronic signal and output the second PPG electronic signal as a digital data value stream representing the PPG waveform.

10. The electronic wearable device according to claim 1, wherein, The first light emitter is positioned at a first location on the bottom wall, the second light emitter is positioned at a second location on the bottom wall, and the light receiver is positioned at a third location on the bottom wall.

11. An electronic wearable device, comprising: A housing, the housing including a bottom wall configured to contact a user's skin; Multiple modulators, each modulator being configured to output one of a plurality of modulated electronic signals, each modulated electronic signal having a predetermined carrier frequency; Multiple light emitters are positioned on the bottom wall and configured to output multiple light signals. Each light emitter is coupled to one of the multiple modulators and configured to receive one of the modulated electronic signals and output a light signal that enters the user's skin corresponding to the carrier frequency of the modulated electronic signal. An optical receiver, positioned on the bottom wall and configured to receive the plurality of optical signals from the user's skin as broadband electronic signals, and to output the broadband electronic signals, the broadband electronic signals comprising optical signals associated with at least two carrier frequencies; and Multiple receiver processor circuits, each configured to receive the broadband electronic signal and output one of a plurality of photoplethysmography (PPG) electronic signals corresponding to one of the plurality of optical signals.

12. The electronic wearable device according to claim 11, wherein, Each receiver processor circuit is electrically coupled to the optical receiver and includes: A filter, configured to output a filtered electronic signal corresponding to one of a plurality of carrier frequencies, and A demodulator configured to receive the filtered electronic signal and output one of the plurality of PPG electronic signals.

13. The electronic wearable device according to claim 12, wherein, At least two of the plurality of light emitters are positioned at a first location on the bottom wall, and the light receiver is positioned at a second location on the bottom wall.

14. The electronic wearable device according to claim 11, wherein, The first optical emitter of the plurality of optical emitters is positioned at a first location on the bottom wall, the second optical emitter of the plurality of optical emitters is positioned at a second location on the bottom wall, and the optical receiver is positioned at a third location on the bottom wall.

15. The electronic wearable device according to claim 11, wherein, Each modulator includes a transconductance amplifier, wherein each of the plurality of optical emitters is a light-emitting diode (LED), and wherein the optical receiver of the plurality of optical receivers is a photodiode configured to receive the optical signal and output the broadband electronic signal having a frequency including the carrier frequency.

16. An electronic wearable device, comprising: A housing, the housing including a bottom wall configured to contact a user's skin; A first modulator, configured to output a first modulated electronic signal having a first carrier frequency; A second modulator is configured to output a second modulated electronic signal having a second carrier frequency; A first light emitter, coupled to the first modulator, is positioned on the bottom wall and configured to output a first light signal based on the first modulated electronic signal, the first light signal being output into the user's skin and having the first carrier frequency; A second light emitter, coupled to the second modulator, is positioned on the bottom wall and configured to output a second light signal based on the second modulated electronic signal, the second light signal being output into the user's skin and having the second carrier frequency; An optical receiver, positioned on the bottom wall and configured to receive the first optical signal and the second optical signal from the user's skin as an analog broadband electronic signal, and output the analog broadband electronic signal, the analog broadband electronic signal comprising the first optical signal and the second optical signal respectively associated with the first carrier frequency and the second carrier frequency; An analog-to-digital converter, configured to receive the analog broadband electronic signal and output the broadband electronic signal as a digital data value stream corresponding to the first optical signal and the second optical signal; A memory element configured to store a first carrier frequency corresponding to the first optical signal and a second carrier frequency corresponding to the second optical signal; and A processor, coupled to the analog-to-digital converter and the memory element, is configured to: Receive the digital broadband electronic signal having a first carrier frequency component and a second carrier frequency component. A first filtered electronic signal and a second filtered electronic signal, respectively having the first carrier frequency and the second carrier frequency, are generated. The first filtered electronic signal and the second filtered electronic signal are demodulated by extracting the amplitudes of the first carrier frequency and the second carrier frequency, respectively. The outputs a first PPG electronic signal and a second PPG electronic signal, which correspond to the first filtered electronic signal after demodulation and the second filtered electronic signal after demodulation, respectively.

17. The electronic wearable device according to claim 16, wherein, The broadband electronic signal includes the first carrier frequency and the second carrier frequency as frequency components.

18. The electronic wearable device according to claim 16, wherein, The first modulator and the second modulator each include a transconductance amplifier, wherein the first light emitter and the second light emitter are each light-emitting diodes (LEDs), and wherein the light receiver is a photodiode.

19. The electronic wearable device according to claim 16, wherein, The first light emitter and the second light emitter are positioned at a first location on the bottom wall, and the light receiver is positioned at a second location on the bottom wall.

20. The electronic wearable device according to claim 16, wherein, The first light emitter is positioned at a first location on the bottom wall, the second light emitter is positioned at a second location on the bottom wall, and the light receiver is positioned at a third location on the bottom wall.

Images