Signal processing system and method

Abstract

The embodiment of the invention provides a signal processing system. The signal processing system comprises an electrode used for being attached to a human body to collect physiological signals; the processing circuit is used for reading the physiological signals in a time-sharing mode, the processing circuit has different input impedance in different time periods, the physiological signals read by the processing circuit comprise different proportions of motion artifact signals, and the processing circuit recognizes the physiological signals based on the different proportions of motion artifact signals.

Description

Signal processing system and method Technical Field

[0001] This specification relates to the field of signal processing, and in particular to signal processing systems and methods. Background Art

[0002] During the process of collecting physiological signals (such as electrocardiograms) from the subject, the subject's movements (such as running, jumping, etc.) will cause the collected physiological signals to also contain motion artifacts (MA), resulting in errors compared to the actual physiological signals. In order to eliminate motion artifacts, the usual practice is to add sensors for measuring motion artifacts in addition to the electrodes used to collect physiological signals to collect motion artifacts, and then eliminate the motion artifacts contained in the physiological signals based on the collected motion artifacts. However, since the working principle of the sensor is different from that of the electrode, the motion artifacts it identifies will also be different from the motion artifacts collected by the electrode. Therefore, the physiological signals obtained based on this method are still not accurate enough.

[0003] Based on this, it is desired to propose a signal processing system and method that can more accurately eliminate the interference of motion artifacts on physiological signals.

[0004] Summary of the Invention

[0005] One of the embodiments of this specification provides a signal processing system, which includes: electrodes for fitting to a human body to collect physiological signals; and a processing circuit for reading the physiological signals in time-sharing mode, wherein the processing circuit has different input impedances in different time periods, and the physiological signals read by the processing circuit contain motion artifact signals in different proportions, and the processing circuit identifies the physiological signals based on the motion artifact signals in different proportions.

[0006] One of the embodiments of the present specification provides another signal processing system, which includes: two groups of electrodes, each group of electrodes in the two groups of electrodes is used to fit the human body to collect physiological signals; and a processing circuit, which is used to read the physiological signals collected by each group of electrodes respectively, wherein the processing circuit has different input impedances when reading the physiological signals collected by different groups of electrodes, and the physiological signals collected by the different groups of electrodes read by the processing circuit contain motion artifact signals in different proportions, and the processing circuit identifies the physiological signals based on the motion artifact signals in different proportions.

[0007] One of the embodiments of this specification provides a signal processing method, which includes: collecting physiological signals through electrodes that are in contact with the human body; and reading the physiological signals in a time-sharing manner through a processing circuit, wherein the processing circuit has different input impedances in different time periods, and the physiological signals read by the processing circuit contain motion artifact signals in different proportions, and the processing circuit identifies the physiological signals based on the motion artifact signals in different proportions.

[0008] One of the embodiments of this specification provides another signal processing method, which includes: collecting physiological signals through each group of electrodes in two groups of electrodes that are in contact with the human body; and reading the physiological signals collected by each group of electrodes separately through a processing circuit, wherein the processing circuit has different input impedances when reading the physiological signals collected by different groups of electrodes, and the physiological signals collected by the different groups of electrodes read by the processing circuit contain motion artifact signals in different proportions, and the processing circuit identifies the physiological signals based on the motion artifact signals in different proportions. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present application will be further described in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, like numbers represent like structures, wherein:

[0010] FIG1 is a schematic diagram of an application scenario of a signal processing system according to some embodiments of this specification;

[0011] FIG2 is a module diagram of a signal acquisition device according to some embodiments of this specification;

[0012] FIG3 is a diagram of a signal transmission path during physiological signal acquisition according to some embodiments of this specification;

[0013] FIG4 is a diagram of electrocardiographic signals collected under different input impedances according to some embodiments of this specification;

[0014] FIG5 is a diagram of a signal transmission path during motion artifact signal acquisition according to some embodiments of this specification;

[0015] FIG6 is a schematic diagram of a processing circuit according to some embodiments of this specification;

[0016] FIG7 is an electrocardiogram signal diagram including motion artifacts caused by relative displacement of horizontal motion according to some embodiments of the present specification;

[0017] FIG8 is an electrocardiogram signal diagram including motion artifacts caused by relative displacement of vertical motion according to some embodiments of the present specification;

[0018] FIG9 is a diagram of an electrocardiogram signal including motion artifacts caused by compression according to some embodiments of the present specification;

[0019] FIG10A is a circuit diagram of a processing circuit of a signal processing system according to some embodiments of this specification;

[0020] FIG10B is a circuit diagram of a processing circuit of a signal processing system according to some embodiments of this specification;

[0021] FIG10C is a circuit diagram of a processing circuit of a signal processing system according to some embodiments of this specification;

[0022] FIG11 is a circuit diagram of another processing circuit of a signal processing system according to some embodiments of this specification;

[0023] FIG12 is a circuit diagram of a processing circuit of another signal processing system according to some embodiments of this specification;

[0024] FIG13 is an exemplary flowchart of a signal processing method according to some embodiments of this specification;

[0025] FIG14 is an exemplary flowchart of another signal processing method according to some embodiments of this specification. DETAILED DESCRIPTION

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0027] It should be understood that the terms "system," "device," "unit," and / or "module" used herein are a method for distinguishing different components, elements, parts, portions, or assemblies at different levels. However, if other terms can achieve the same purpose, the terms may be replaced by other expressions.

[0028] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0029] Flowcharts are used in this application to illustrate the operations performed by the systems according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0030] FIG1 is a schematic diagram of an application scenario of a signal processing system according to some embodiments of this specification.

[0031] 1 , in some embodiments, a signal processing system 100 (hereinafter referred to as system 100) may include a processing device 110, a network 120, a storage device 130, a terminal device 140, a signal acquisition device 150, and an acquisition target 160. The various components of system 100 may be connected in various ways. For example, signal acquisition device 150 may be connected to storage device 130 and / or processing device 110 via network 120, or directly to storage device 130 and / or processing device 110. For another example, storage device 130 may be connected to processing device 110 directly or via network 120. For another example, terminal device 140 may be connected to storage device 130 and / or processing device 110 via network 120, or directly to storage device 130 and / or processing device 110.

[0032] In some embodiments, the system 100 can collect and identify physiological signals by implementing the methods and / or processes disclosed in this specification.

[0033] Physiological signals may refer to bioelectrical signals from the human body, such as electrocardiogram (ECG) signals and electromyographic (EMG) signals, collected by a signal acquisition device (e.g., signal acquisition device 150). Physiological signals may be mixed signals containing motion artifact (MA) signals and pure physiological signals. Pure physiological signals may refer to true physiological signals of the subject 160 obtained by filtering out motion artifact signals based on physiological signal recognition. For detailed descriptions of the methods for collecting and identifying physiological signals, please refer to Figures 3, 5, 10A-14, and their related descriptions.

[0034] The processing device 110 can process data and / or information obtained from the signal acquisition device 150, the storage device 130, the terminal device 140, and / or other components of the system 100. In some embodiments, the processing device 110 can obtain physiological signals of the subject 160 from any one or more of the signal acquisition device 150, the storage device 130, or the terminal device 140, and then identify the physiological signals. In some embodiments, the processing device 110 can retrieve pre-stored computer instructions from the storage device 130 and execute the computer instructions to implement the signal processing methods described herein.

[0035] In some embodiments, the processing device 110 can be a single server or a server group. The server group can be centralized or distributed. In some embodiments, the processing device 110 can be local or remote. For example, the processing device 110 can access information and / or data from the signal acquisition device 150, the storage device 130, and / or the terminal device 140 via the network 120. For another example, the processing device 110 can be directly connected to the signal acquisition device 150, the storage device 130, and / or the terminal device 140 to access information and / or data. By way of example only, the processing device 110 can be directly connected to the signal acquisition device 150 via a wired connection (e.g., wires, circuit boards, etc.), allowing the processing device 110 to directly access the data or signals collected by the signal acquisition device 150 for processing. In some embodiments, the processing device 110 can be implemented on a cloud platform. For example, the cloud platform can include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an inter-cloud cloud, a multi-cloud, or any combination thereof. In some embodiments, the processing device 110 can be implemented on a terminal device (e.g., the terminal device 140).

[0036] The network 120 can connect the various components of the system 100 and / or connect the system 100 with external resources. The network 120 enables communication between the various components of the system 100, as well as with other components outside the system 100, to facilitate the exchange of data and / or information. For example, the processing device 110 can obtain physiological signals from the signal acquisition device 150 and / or the storage device 130 via the network 120. For another example, the processing device 110 can obtain user operation instructions from the terminal device 140 via the network 120. Exemplary operation instructions may include, but are not limited to, setting the collection subject information (e.g., gender, age, height, weight, medical history, etc.).

[0037] In some embodiments, network 120 can be any form of wired or wireless network, or any combination thereof. By way of example only, network 120 can include a cable network, a wired network, a fiber optic network, a telecommunications network, an intranet, the Internet, a local area network (LAN), a wide area network (WAN), a wireless local area network (WLAN), a metropolitan area network (MAN), a public switched telephone network (PSTN), a Bluetooth network, a ZigBee network, a near-field communication (NFC) network, or the like, or any combination thereof. In some embodiments, network 120 can include at least one network access point, and at least one component of system 100 can connect to network 120 via the access point to exchange data and / or information. For example, data such as collected physiological signals can be transmitted via network 120.

[0038] The storage device 130 can store data, instructions, and / or any other information. In some embodiments, the storage device 130 can store data obtained from the signal acquisition device 150, the processing device 110, and / or the terminal device 140. For example, the storage device 130 can store physiological signals acquired by the signal acquisition device 150. In some embodiments, the storage device 130 can store data and / or instructions used by the processing device 110 to execute or complete the exemplary methods described herein. In some embodiments, the storage device 130 can include a mass storage device, a removable memory, a volatile read-write memory, a read-only memory (ROM), or the like, or any combination thereof. Exemplary mass storage devices can include magnetic disks, optical disks, solid-state disks, and the like. In some embodiments, the storage device 130 can be implemented on a cloud platform. By way of example only, the cloud platform can include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an internal cloud, a multi-layer cloud, or the like, or any combination thereof.

[0039] In some embodiments, the storage device 130 can be connected to the network 120 to communicate with at least one other component in the system 100 (e.g., the signal acquisition device 150, the processing device 110, or the terminal device 140). At least one component in the system 100 can access data, instructions, or other information stored in the storage device 130 via the network 120. In some embodiments, the storage device 130 can be directly connected to or communicate with one or more components in the system 100 (e.g., the signal acquisition device 150 or the terminal device 140). In some embodiments, the storage device 130 can be part of the signal acquisition device 150 and / or the processing device 110.

[0040] The terminal device 140 can receive, transmit, and / or display data. The received data may include data collected by the signal acquisition device 150, data stored by the storage device 130, data generated by the processing device 110, and the like. For example, the data received and / or displayed by the terminal device 140 may include physiological signals collected by the signal acquisition device 150, pure physiological signals obtained by the processing device 110 through physiological signal recognition, and the like. The transmitted data may include user input data and instructions. For example, the terminal device 140 may transmit user-entered operating instructions to the signal acquisition device 150 via the network 120 to control the signal acquisition device 150 to perform corresponding data acquisition.

[0041] In some embodiments, the terminal device 140 may include a mobile device 141, a tablet computer 142, a laptop computer 143, or any combination thereof. For example, the mobile device 141 may include a mobile phone, a personal digital assistant (PDA), a medical mobile terminal, a wearable device (e.g., a smartwatch, a wristband, etc.), or any combination thereof. In some embodiments, the terminal device 140 may include an input device (e.g., a keyboard, a touch screen), an output device (e.g., a display, a speaker), or the like. In some embodiments, the processing device 110 may be part of the terminal device 140.

[0042] The signal acquisition device 150 may be a device for collecting physiological signals from the subject 160. In some embodiments, the signal acquisition device 150 may include at least one electrode, which may be adapted to contact at least one body part of the subject 160 to collect physiological signals from the subject 160. In some embodiments, the signal acquisition device 150 may have an independent power supply and may transmit the collected data to other components (e.g., the processing device 110, the storage device 130, the terminal device 140) via wired or wireless means (e.g., Bluetooth, WiFi, etc.). In some embodiments, one or more components of the system 100 may be implemented on the signal acquisition device 150. For example, the signal acquisition device 150 may include the processing device 110, the storage device 130, etc.

[0043] The collection object 160 may be a user of the signal collection device 150 , for example, a patient, an experimenter, an athlete, a fitness enthusiast, an elderly person, etc., who needs to collect physiological signals.

[0044] It should be noted that the above description of system 100 is for illustration and purpose only and does not limit the scope of application of this specification. Those skilled in the art will be able to make various modifications and changes to system 100 under the guidance of this specification. However, such modifications and changes are still within the scope of this specification.

[0045] FIG2 is a block diagram of a processing system according to some embodiments of this specification. In some embodiments, the signal acquisition device 150 described in FIG1 can be implemented by a signal processing system 200. As shown in FIG2, the signal processing system 200 may include an electrode 210 and a processing circuit 220.

[0046] Electrode 210 can be used to attach to human skin and collect physiological signals. As shown in Figure 2, electrode 210 includes at least a first electrode 211 and a second electrode 212. Electrode 210 can be attached to different parts of the human body. The part attached to first electrode 211 has a first potential, and the part attached to second electrode 212 has a second potential. Physiological signals can be determined based on the difference between the first and second potentials.

[0047] Physiological signals may include bioelectric signals such as electrocardiogram (ECG) and electromyography (EMG). For a detailed description of physiological signals, please refer to FIG1 .

[0048] In some embodiments, the physiological signal may be an electrocardiogram (ECG) signal. In this regard, in some embodiments, the first electrode 211 and the second electrode 212 may be attached to two locations at different distances from the heart of the subject 160, respectively, to collect the potentials (the first potential and the second potential) at these two locations. Subsequently, the ECG signal may be determined based on the difference between the potentials at these two locations.

[0049] In some embodiments, the first electrode 211 and the second electrode 212 can be located on both sides of the median sagittal plane of the human body, respectively, to detect the potentials (first potential and second potential) on both sides of the median sagittal plane of the human body, and then the electrocardiogram signal can be determined based on the difference between the potentials on both sides of the median sagittal plane of the human body.

[0050] The midsagittal plane of the human body is the plane that passes through the midline of the body and divides the body into two equal or approximately equal parts. The midline of the human body can be determined by the line from the tip of the nose to the middle of the two nipples, the line from the middle of the two nipples to the middle of the umbilicus, or the line from the middle of the umbilicus to the middle of the pubic symphysis.

[0051] In some embodiments, the first electrode 211 and the second electrode 212 can also be applied to the skin of the waist region on both sides of the midsagittal plane of the human body. The waist region of the human body can be the area between the lower end of the ribs and the lower end of the ilium, which mainly includes the abdomen and the ilium. The midsagittal plane of the human body can divide the waist region into the left waist region and the right waist region. In some embodiments, the first electrode 211 and the second electrode 212 can be applied to the skin of the left waist region and the right waist region, respectively. In some embodiments, the first electrode 211 and the second electrode 212 can be applied to the skin of the left and right waist regions, respectively. In some embodiments, the first electrode 211 and the second electrode 212 can be applied to the skin of the left and right hips, respectively. In some embodiments, the first electrode 211 and the second electrode 212 can be applied to the skin of the left and right knee joints, respectively. In some embodiments, the first electrode 211 and the second electrode 212 can be applied to the skin of the left and right ankles, respectively. It is understood that the first electrode 211 and the second electrode 212 can also be applied to other parts of the body, such as the skin of the left and right thighs, the skin of the left and right calves, etc.

[0052] In some embodiments, the physiological signal can be an electromyographic signal. Based on this, the first electrode 211 and the second electrode 212 can be used to collect the electromyographic signal of the same muscle of the user. The same muscle can refer to a single muscle or the same muscle group (for example, the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius quadriceps muscle group). For example, when the user wears the signal acquisition device 150, the first electrode 211 and the second electrode 212 can be close to the middle area of ​​the muscle in the muscle fiber direction (or muscle length direction). The first electrode 211 and the second electrode 212 can be arranged at intervals along the muscle fiber direction of the muscle and extend respectively along an extension direction perpendicular to the muscle fiber direction. Different positions in the muscle fiber direction have different electric potentials. The position of the muscle fiber where the first electrode 211 is located has a first electric potential, and the position of the muscle fiber where the second electrode 212 is located has a second electric potential. There is a potential difference between the first potential and the second potential, and the electromyographic signal can be determined based on the potential difference.

[0053] In some embodiments, the electrodes may further include a reference electrode, which may be used to provide a reference potential for the first electrode and / or the second electrode, thereby reducing noise interference.

[0054] In some embodiments, the electrode 210 can be fixed to the wearable body through a base structure. For example, the base structure can be made of a flexible insulating material (e.g., resin, soft PVC, silicone, fabric, etc.), and the electrode 210 can be fixedly connected to the base structure by pasting, snapping, welding, stitching, hot pressing, etc., and further fixed to the wearable body through the base structure. In some embodiments, the base structure can be omitted, and the electrode 210 can also be integrally formed with the wearable body (e.g., integrally woven, etc.). When the user wears the signal acquisition device 150, the electrode 210 can contact the skin of the collection object.

[0055] The processing circuit can be used to read physiological signals in a time-sharing manner. Time-sharing reading can include: the processing circuit having different input impedances in different time periods; and the physiological signals read by the processing circuit in different time periods contain different proportions of motion artifact signals. In some embodiments, the multiple time periods of the time-sharing can be non-overlapping. In some embodiments, time-sharing reading by the processing circuit can be achieved by reading (or sampling) physiological signals from multiple channels through time-sharing multiplexing (e.g., a time-sharing multiplexing switch). The switching time required for the time-sharing multiplexing switch is relatively short (e.g., less than 1 μs), and the multiple time periods of the time-sharing can be continuous or nearly continuous. In some embodiments, the durations of the multiple time periods can be the same (i.e., evenly divided) or different. In some embodiments, the duration of one of the multiple time periods can be a preset value. In some embodiments, different strategies can be employed when implementing time-sharing reading by the processing circuit through time-sharing multiplexing. Exemplary strategies include a complete signal reconstruction strategy and a signal splicing strategy. In different strategies, the duration of one of the multiple time periods can be different. In other words, the preset value of the duration can be determined based on the strategy employed for time-sharing multiplexing.

[0056] For example, a fully reconstructed signal strategy can involve rapidly switching a time-division multiplexing switch to sample signals from each sampling channel, thereby reconstructing the original signal at a higher sampling frequency. Rapidly switching the time-division multiplexing switch can mean that the switching frequency of the time-division multiplexing switch is greater than the frequency of the target signal to be sampled (e.g., a heart rate signal, an electromyographic signal, etc.). For example, the sampling frequency (i.e., the switching frequency of the corresponding time-division multiplexing switch) can be greater than or equal to 2 times, 5 times, or the like, the target signal frequency. Therefore, the switching frequency of the time-division multiplexing switch can be determined based on the frequency of the target signal, thereby determining the duration of one of the multiple time periods. For example, the frequency of the target signal can be 10 Hz, and the corresponding switching frequency can be greater than or equal to 20 Hz when sampling through a single channel. If the signal is sampled through n channels, the corresponding switching frequency can be greater than or equal to 20*n Hz. By way of example only, the processing circuit 220 can include two signal processing subcircuits, i.e., sampling through two channels. Accordingly, the switching frequency of the time-division multiplexing switch can be greater than or equal to 40 Hz, and the duration of the corresponding time period can be less than or equal to 25 ms. In addition, a too fast switching frequency of the time-division multiplexing switch may cause resource consumption, and the switching frequency is limited by the system capacitance effect. Therefore, the switching frequency cannot be too high. For example, when using a single channel for acquisition, the switching frequency is no more than 100KHz, and the corresponding time period can be greater than or equal to 10μs. For example, using the full reconstruction signal strategy for signal acquisition, when the number of channels n = 2, the switching frequency of the time-division multiplexing switch can be 40Hz-200KHz, and the corresponding time period can be preset within the range of 5μs-25ms; or, when the number of channels n = 2, the switching frequency of the time-division multiplexing switch can be 80Hz-100KHz, and the corresponding time period can be preset within the range of 10μs-12.5ms; or, when the number of channels n = 2, the switching frequency of the time-division multiplexing switch can be 160Hz-20KHz, and the corresponding time period can be preset within the range of 50μs-6.25ms.

[0057] For another example, taking the splicing signal strategy as an example, the splicing signal strategy can refer to slowly switching a time-sharing multiplexing switch to sample signals from each sampling channel. The slow switching of the time-sharing multiplexing switch can mean that the switching frequency of the time-sharing multiplexing switch is less than the frequency of the target signal to be sampled and greater than the motion frequency of the subject in motion. For example, the sampling frequency (i.e., the switching frequency of the corresponding time-sharing multiplexing switch) can be greater than or equal to 2 times, 5 times, etc., of the motion frequency of the subject in motion. This allows a series of frequency signals to be acquired within each time period. Because the switching of the time-sharing multiplexing switch is fast relative to the motion frequency, the signals between multiple channels still have reference value. Therefore, the switching frequency of the time-sharing multiplexing switch can be determined based on the frequency of the motion corresponding to the target signal, thereby determining the duration of one of the multiple time periods. For example, the frequency of running is 3Hz, which means that the subject can complete a running motion within 0.33 seconds. Therefore, when analyzing the target signal (e.g., electromyographic signal), signals within 0.33 seconds can be distinguished. As an example, the signal within 0.33s can be divided into 10 parts for analysis, and the duration of each corresponding time period can be 33ms. In some embodiments, when the target signal is a high-frequency signal and the action is a low-frequency action, for example, when the action period of a fitness action is 2s and the corresponding electromyographic signal is at the 100Hz level, the switching frequency of the time-division multiplexing switch can be determined based on the frequency of the action corresponding to the target signal, and then the duration of one of the multiple time periods can be determined. As an example, taking the splicing signal strategy for signal acquisition as an example, when the number of channels n = 2, the switching frequency of the time-division multiplexing switch can be greater than 0.4Hz, and the duration of the corresponding time period can be less than 2.5s; alternatively, when the number of channels n = 2, the switching frequency of the time-division multiplexing switch can be between 0.5Hz and 200Hz, and the duration of the corresponding time period can be in the range of 5ms to 2s; alternatively, when the number of channels n = 2, the switching frequency of the time-division multiplexing switch can be between 1Hz and 100Hz, and the duration of the corresponding time period can be in the range of 10ms to 1s. In some embodiments, the sampling frequency can be measured in reverse based on the processing circuit. For example, the processing circuit may include an ADC (Analog-Digital Converter) circuit. Based on the sampling principle of the ADC, a measurement circuit for measuring the sampling frequency may be introduced at the tube end of the ADC circuit. The measurement circuit may be used to measure changes in parameters (e.g., capacitance, inductance, resistance, etc.) when the processing circuit performs ADC sampling, thereby determining the sampling frequency.

[0058] In some embodiments, the processing circuit can identify physiological signals based on different proportions of motion artifact signals. Identifying physiological signals can mean filtering out motion artifact signals from the collected physiological signals, thereby obtaining a pure physiological signal with no or minimal motion artifact signals. For more information about the processing circuit, see Figures 10A-12 and the related descriptions.

[0059] During the physiological signal acquisition process, the collected physiological signals contain motion artifacts (MA) due to the movement of the subject (e.g., running, jumping, etc.). Motion artifacts primarily originate from the skin interface where the electrodes meet. Taking the electrocardiogram (ECG) as an example, motion artifacts can include half-cell potentials. Half-cell potentials refer to the potential generated by changes in electrode position and / or pressure on the skin caused by movement, which can result in motion artifacts in the collected ECG signals.

[0060] According to the voltage division principle of series circuits, the greater the input impedance of the processing circuit, the greater the voltage divided by the processing circuit when collecting physiological signals.

[0061] The voltage division principle of the series circuit can be explained by the following formula (1): V1=(R1 / (R1+R2+…+R n ))×V, (1)

[0062] Among them, V1 is the voltage divided by the resistor R1 in the circuit, (R1+R2+…+R n ) is the total impedance of the circuit including R1, 1, 2, ..., n are the resistor numbers, and V is the power supply voltage (i.e., the total circuit voltage). Therefore, if the impedance of the other resistors in the circuit and the total circuit voltage remain unchanged, if the impedance of R1 increases, the voltage V1 distributed across R1 will also increase.

[0063] Physiological signals originate beneath the skin, while motion artifact signals primarily originate at the skin interface. The difference between physiological and motion artifact signals can be distinguished by the fact that motion artifact signals can be acquired without passing through the skin impedance, primarily the stratum corneum. Based on this, the difference between physiological and motion artifact signals can be amplified using the principle of voltage division, taking advantage of the different input impedances of the processing circuitry.

[0064] Figure 3 is a diagram of the signal transmission path during physiological signal acquisition according to some embodiments of this specification. As shown in Figure 3, ECG represents the physiological signal source, R1 is the skin impedance mainly composed of the stratum corneum, R2 is the contact impedance, R3 is the input impedance of the processing circuit (for example, the impedance between the signal input end of the processing circuit and the reference ground), and the triangle surrounding R3 represents the processing circuit of the signal acquisition device. Among them, the physiological signal source is located inside the human body (for example, muscle, heart), and the contact impedance R2 refers to the impedance generated when the signal propagates in different media (electrode and skin) at the point where the electrode and the skin are in contact. In some embodiments, the contact impedance R2 may also include skin impedance fluctuations, electrode impedance fluctuations, etc.

[0065] Taking the ECG signal as an example, since the heart is located inside the body, the ECG signal, to be transmitted to the signal acquisition device, must first pass through the skin impedance R1, primarily the stratum corneum, then the contact impedance R2, and finally the input impedance R3 of the processing circuit. If the input impedance R3 is much larger than the other impedances, the voltage divided by R3 accounts for a larger proportion of the voltage corresponding to the ECG signal (hereinafter referred to as the ECG voltage, the magnitude of which can indicate the strength of the ECG signal), allowing the ECG signal to be fully acquired by the processing circuit. Conversely, if R3 is much smaller than the other impedances, the ECG voltage will be primarily divided by the other impedances in the processing circuit (e.g., R1 and R2). The ECG voltage divided by the input impedance R3 will be correspondingly small, resulting in the processing circuit being unable to fully acquire the ECG signal. Therefore, a larger input impedance (e.g., on the order of 1 GΩ) can be used for physiological signal acquisition (the acquired physiological signal will still be a mixed signal containing motion artifacts). Based on this, the acquired physiological signal includes a relatively pure physiological signal.

[0066] FIG4 is a diagram of electrocardiographic signals collected under different input impedances according to some embodiments of this specification.

[0067] As shown in Figure 4, ECG signals were measured for input impedances of 2kΩ, 10kΩ, and 50kΩ, respectively. (The regular "glitch" in the figure is the ECG signal. "Glitch" can refer to peaks or valleys in the ECG signal graph with amplitudes greater than the average amplitude, such as glitches 410, 420, and 430 in Figure 4.) From top to bottom in Figure 4, as the input impedance increases, the ECG gradually becomes more distinct. This indicates that increasing the input impedance can increase the proportion of pure ECG signals in the collected ECG signal, so that the measured signal primarily consists of pure ECG signals.

[0068] In some embodiments, the proportion of pure ECG signals in the collected ECG signals can be reduced by lowering the input impedance, so that the collected signals primarily include motion artifact signals. Thus, a pure ECG signal can be obtained based on the ECG signal collected by a processing circuit using a large input impedance and the ECG signal collected by a processing circuit using a small input impedance (primarily containing motion artifact signals). For example, the pure ECG signal can be obtained by subtracting the ECG signal collected by a processing circuit using a small input impedance (primarily containing motion artifact signals) from the ECG signal collected by the processing circuit using a large input impedance.

[0069] FIG5 is a diagram of the transmission path of a signal during motion artifact signal acquisition according to some embodiments of the present specification. As shown in FIG5 , MA is a motion artifact source, R2 is a contact impedance, R3 is an input impedance of a processing circuit, and the triangle surrounding R3 represents a processing circuit of a signal acquisition device. A motion artifact source may refer to a source that generates a motion artifact signal (e.g., a change in electrode position caused by movement and / or a change in electrode pressure on the skin, resulting in a change in potential at the electrode contact point). Since the motion artifact source is located outside the stratum corneum of the skin, its transmission process does not need to pass through the skin impedance R1, which is mainly composed of the stratum corneum.

[0070] On this basis, taking the physiological signal as an ECG signal as an example, using a smaller input impedance R3 (for example, on the order of 1KΩ) can make the proportion of pure ECG signals in the collected ECG signal smaller while the proportion of motion artifact signals is larger. The strength of the motion artifact signal collected by the input impedance R3 (which can be characterized by the voltage corresponding to the motion artifact signal, which will be referred to as the motion artifact voltage in the future, and its magnitude can represent the strength of the motion artifact signal) is related to the fluctuation of the motion artifact source (for example, changes in electrode position and / or changes in electrode pressure on the skin caused by movement), changes in the impedance magnitude of the contact impedance R2, etc. When the impedance value of the input impedance R3 becomes smaller, the measured ECG voltage becomes smaller, which in turn causes the value of the motion artifact voltage contained in the collected ECG voltage to become smaller. However, since there is no voltage divider of the skin impedance R1 mainly composed of the stratum corneum, the degree of reduction in the motion artifact voltage caused by the reduction of R3 will be less than the degree of reduction in the ECG voltage. On the other hand, with respect to changes in the magnitude of the contact impedance R2, the magnitude of the motion artifact voltage collected by the input impedance R3 due to changes in the magnitude of the contact impedance R2 will increase due to the decrease in the input impedance R3, wherein the decrease in R3 may refer to a decrease within a preset range, for example, the minimum value of R3 within the preset range is of the same order of magnitude as the magnitude of R2. Specifically, although the motion artifact voltage collected by the input impedance R3 will decrease due to the decrease in R3, the degree of decrease is not as great as the degree of decrease in the ECG voltage collected by the input impedance R3. This setting can make the motion artifact signal more prominent, so that the motion artifact voltage collected by the input impedance R3 due to changes in the magnitude of the contact impedance R2 will increase as R3 decreases (it can be understood that the motion artifact signal is more sensitive to changes in R2, and a smaller change in the magnitude of R2 can produce a larger change in the motion artifact signal). Therefore, an input impedance R3 with a smaller impedance value (e.g., on the order of 1 kΩ) can be used for signal acquisition, and the collected ECG signal mainly contains the motion artifact signal and a small proportion of the pure ECG signal.

[0071] More specifically, the relationship between the strength of the motion artifact signal collected by the input impedance R3 and the fluctuation of the motion artifact source can be described by the following formula (2): ma1=(r3 / (r2+r3))×ΔV (2)

[0072] Among them, ma1 is the motion artifact voltage corresponding to the fluctuation of the motion artifact source, r2 is the impedance value of the contact impedance R2, r3 is the impedance value of the input impedance R3, and ΔV is the fluctuation of the motion artifact source.

[0073] The relationship between the strength of the motion artifact signal collected by the input impedance R3 and the change in the impedance of the contact impedance R2 can be described by the following formula (3): ma2=(r3 / (r2+Δr2+r3))×V (3)

[0074] Wherein, ma2 is the motion artifact voltage corresponding to the impedance change of the contact impedance R2, Δr2 is the change in the impedance value of the contact impedance R2, r3 is the impedance value of the input impedance R3, and V is the real motion artifact signal.

[0075] Combining formulas (2) and (3) and the above analysis, it can be seen that an input impedance R3 with a relatively small impedance value (e.g., on the order of 1 kΩ) can be used for signal acquisition. The acquired ECG signal mainly contains motion artifact signals and a small proportion of pure ECG signals. For example, the input impedance R3 can be set to the same order of magnitude as the contact impedance R2. Furthermore, the input impedance R3 can be set to be close to the contact impedance R2. As an example only, the ratio of the input impedance R3 to the contact impedance R2 can be set within a range of 0.1-10, 0.2-5, 0.4-2.5, etc.

[0076] In some embodiments of this specification, differentiated input impedances are used to separately collect physiological signals and motion artifact signals, so that when the input impedance is large, the circuit mainly collects ECG signals, while when the input impedance is small, the ECG signals become correspondingly smaller and the motion artifact signals are enhanced. Subsequently, analysis and calculation based on the correlation algorithm can be performed to identify pure physiological signals and achieve physiological signal denoising.

[0077] The processing circuit can be used to read the physiological signals collected by a set of electrodes in a time-sharing manner. To achieve this function, the entire transmission time corresponding to the signal reading can be divided into multiple time periods. The processing circuit can have different input impedances in different time periods, so that different input impedances can be used in different time periods to achieve time-sharing reading of physiological signals. As an example, the transmission time can be divided into n time periods, and the processing circuit can have at least two input impedances, with different input impedances used in adjacent time periods. For example, the input impedance in the first time period is a, the input impedance in the second time period is b, the input impedance in the third time period is a, the input impedance in the fourth time period is b, and so on. In some embodiments, the multiple time periods can be continuous and non-overlapping. In some embodiments, the duration of the multiple time periods can be the same (i.e., evenly divided) or different. In some embodiments, the duration of a time period can be a preset value. For example, the duration of a time period in the multiple time periods can be determined based on the frequency of the target signal. For another example, the duration of a time period in the multiple time periods can be determined based on the frequency of the action corresponding to the target signal.

[0078] In order to enable the processing circuit to read physiological signals in a time-sharing manner, the structure of the processing circuit can be: the electrode module of the processing circuit includes two electrodes (a first electrode and a second electrode), and the circuit connected thereto includes two branches (called a first branch and a second branch). The input impedance included in the first branch is a large input impedance (for example, an impedance exceeding 1MΩ), and the input impedance included in the second branch is a small input impedance (for example, an impedance of the 100KΩ level). Both branches are connected to the electrode module. This structure can make the motion artifact signal collected by the second branch highly correlated with the motion artifact signal collected by the first branch. In addition, in order to avoid mutual influence between the impedances of the two circuits, the two circuits need to read the signals in a time-sharing manner to achieve isolation of the input impedances of the two circuits.

[0079] Specific implementation method: The processing circuit may include two signal processing sub-circuits (corresponding to the above-mentioned first branch and second branch respectively), and the two signal processing sub-circuits have different resistances, that is, different input impedances. The connection or disconnection of the two sub-circuits to the electrodes can be controlled by a time-sharing multiplexing switch to achieve time-sharing reading. For example, the first time period is connected to the first sub-circuit and disconnected from the second sub-circuit, the second time period is connected to the second sub-circuit and disconnected from the first sub-circuit, the third time period is connected to the first sub-circuit and disconnected from the second sub-circuit... Alternatively, there is only one processing circuit, an additional resistor is connected in parallel to the input end of the circuit, and the connection between this additional resistor and the circuit is controlled by a switch, so that the input impedance of the circuit is different in different time periods. For more details, please refer to Figures 10A, 10B, 11 and related descriptions.

[0080] In some embodiments of this specification, the signals collected by the processing circuit always originate from the same set of electrodes, and a time-division multiplexing method is used to simultaneously collect signals from the same set of electrodes using different input impedances. This configuration allows the MA collected by the low-input-impedance circuit to be highly correlated with the MA of the normal-input-impedance circuit, avoiding acquisition errors caused by connecting different groups of electrodes using different impedances and improving measurement accuracy. Physiological signals read at different time periods contain different proportions of motion artifact signals. The processing circuit can then identify physiological signals based on the different proportions of motion artifact signals.

[0081] In addition to the above implementation, two sets of electrodes can be set in the processing circuit and connected to a large impedance and a small impedance respectively for signal reading. For more details, please refer to Figure 12 and its related description.

[0082] In some embodiments, the different input impedances include at least two input impedances, and the ratio of the larger input impedance to the smaller input impedance of the at least two input impedances is not less than 10. For example, in different time periods, the resistance in the circuit may be different, so that the impedance ratio is not less than 10. Just as an example, the circuit structure as exemplified above: the input impedances of the two sub-circuits may be different, or the input impedance of one of the sub-circuits may be connected in parallel with a resistor and the connection between the resistor and the sub-circuit may be controlled by a switch, so that the impedance ratio is not less than 10. In some embodiments, the ratio of the larger input impedance to the smaller input impedance of the two input impedances may be different at different frequencies. For example, in order to match a relatively low-frequency target signal, for example, when the frequency is 0.5Hz-100Hz, the ratio of the larger input impedance to the smaller input impedance of the two input impedances is not less than 10. For another example, in order to match a relatively high-frequency target signal, for example, when the frequency is greater than 100Hz, the ratio of the larger input impedance to the smaller input impedance of the two input impedances may be further increased, such as not less than 10. ^3 .

[0083] In some embodiments, when the frequency is 50 Hz, the larger input impedance of the two input impedances is not less than 1 MΩ, and the smaller input impedance is not greater than 100 KΩ.

[0084] In some embodiments of the present specification, the above-mentioned resistance setting method can make it possible for the ECG signal to be fully collected by the circuit when the input impedance is large, while when the input impedance is small, the ECG signal becomes correspondingly smaller and the collected motion artifact signal is larger due to the smaller input impedance, making the difference more obvious, thereby improving the recognition accuracy of subsequent physiological signals.

[0085] In some embodiments, the processing circuit can filter out the motion artifact signal and / or enhance the pure physiological signal based on the correspondence between the motion artifact signal and the physiological signal at different ratios, and use the processed physiological signal as the target physiological signal. For example, the processing circuit can identify the motion artifact signal based on the physiological signal read by the low impedance circuit, and then treat the signal with a high correlation with the motion artifact signal from the physiological signal read by the high impedance circuit as the motion artifact signal and filter it out. As an example only, when motion artifacts are caused by factors such as movement (such as running, jumping, etc.), the physiological signal read at low input impedance may show obvious fluctuations (as shown in range A in Figure 6). The processing circuit can identify the signal with obvious fluctuations and use it as the motion artifact signal. Furthermore, the processing circuit can determine the correspondence between the physiological signal read at high input impedance and the motion artifact signal, filter out the motion artifact signal, and / or enhance the pure physiological signal, and use the processed physiological signal as the target physiological signal.

[0086] It should be noted that the above description of the processing system is for convenience of description only and cannot limit this specification to the scope of the embodiments. It is understandable that for those skilled in the art, after understanding the principle of the processing system, it is possible to arbitrarily combine the various modules, or form a subsystem connected to other modules without deviating from this principle. In some embodiments, the electrode 210 processing circuit 220 disclosed in Figure 1 can be different modules, or one module can realize the functions of two or more modules mentioned above. For example, each module can share a storage module, or each module can have its own storage module. Such deformations are all within the protection scope of this specification.

[0087] FIG6 is a schematic structural diagram of a processing circuit according to some embodiments of this specification.

[0088] The processing circuit 600 shown in FIG6 can also implement the acquisition and processing of multiple physiological signals. By employing a time-division multiplexing approach, the processing circuit 600 can achieve the goals of saving space costs and reducing hardware requirements while ensuring the acquisition and processing of multiple signal sources. Specifically, as shown in FIG6 , the processing circuit 600 may include at least two signal acquisition circuits (e.g., a first acquisition circuit 611 and a second acquisition circuit 612, corresponding to the first and second branches described above), a switching circuit 620, an analog circuit 630, and a control circuit 640. In some embodiments, the at least two signal acquisition circuits are used to acquire at least two physiological signals. The first acquisition circuit 611 and the second acquisition circuit 612 may have different input impedances. For example, the first acquisition circuit 611 may have a high input impedance (e.g., an impedance exceeding 1 MΩ), while the second acquisition circuit 612 may have a low input impedance (e.g., an impedance in the order of 100 KΩ). The switching circuit 620 may be used to control the conduction state of each signal acquisition circuit and the analog circuit 630. For example, at a certain point in time, the switch circuit 620 can connect a signal acquisition circuit to the analog circuit 630. By way of example only, at a certain point in time, the switch circuit 620 can connect the electrode module to the first acquisition circuit 611 having a large input impedance, thereby connecting the first acquisition circuit 611 to the analog circuit 630. Within a certain time range, the switch circuit 620 can periodically connect each signal acquisition circuit to the analog circuit 630. When the switch circuit 620 connects a signal acquisition circuit to the analog circuit 630, the signal collected by that signal acquisition circuit can be transmitted to the analog circuit 630 for processing (e.g., noise reduction, amplification, etc.), and the processed signal is then transmitted to the control circuit 640 for signal analysis. It will be appreciated that by providing the switch circuit 620 between multiple signal acquisition circuits and the analog circuit 630, the same analog circuit can process signals from different signal acquisition circuits at different points in time. This effectively reduces the complexity and cost of using multiple analog circuits and also reduces the number of channels for signal transmission between the subsequent analog circuits and the control circuit. It should be noted that the switch circuit 620 and analog circuit 630 shown in FIG6 are for illustrative purposes only. In actual use, more than one switch may be used between the multi-channel signal acquisition circuit and the control circuit 640. In some embodiments, at least two signal acquisition circuits may include different resistors to achieve different input impedances. The switch circuit 620 may also be provided between the electrode module and the resistors to control the connection between the electrode module and the different resistors, thereby achieving signal acquisition circuits with different input impedances. The signal acquisition circuits with different input impedances may be further connected to the analog circuit 630.

[0089] The control circuit 640 samples the signal processed by the analog circuit 630. In some embodiments, the sampling frequency of the control circuit 640 is related to the number of signal acquisition circuits, the control strategy for the switching circuit and the target frequency of the physiological signal. For example, the sampling frequency of each signal by the control circuit 640 is not less than twice its target frequency. Just as an example, for an electromyographic signal, assuming that its corresponding target frequency is within 1000Hz, the control circuit can use a sampling frequency of 2000Hz to sample the electromyographic signal. For the entire signal processing circuit, assuming that there are 4 signal acquisition circuits that collect electromyographic signals, the control circuit 640 is required to provide a total sampling frequency of 8000Hz, so as to ensure that the sampling rate of each electromyographic signal reaches 2000Hz.

[0090] In some embodiments, the switch circuit 620 is used to control the conduction between the at least two signal acquisition circuits and the analog circuit 630, so that at the same time, only the target signals acquired by some of the at least two signal acquisition circuits are transmitted to the analog circuit 630. In some embodiments, the switch circuit 620 can use a switch chip with multiple channels and dual outputs, such as the TMUX1209 switch chip. In different situations, the control circuit 640 can control the switching of the switch circuit 620 based on different strategies. For example, to ensure that subsequent sampled data can fully retain the information of each target signal (i.e., the control circuit 640 can reconstruct each target signal based on the sampled data), the control circuit 640 can use a full reconstruction strategy to control the switching of the switch circuit 620. For another example, considering that the control circuit 640 may not be able to obtain valid sampled data during the rapid switching of the switch channels, the control circuit 640 can use a splicing signal strategy to control the switching of the switch circuit 620.

[0091] The analog circuit 630 is used to process the physiological signals it receives. In some embodiments, because the amplitude of the raw physiological signals directly collected by the signal acquisition circuit is very small and contains a large amount of noise, the analog circuit 630 is required to perform filtering, differential amplification, amplification, negative feedback noise reduction, and other processing on the raw physiological signals. In some embodiments, the analog circuit 630 may include a differential amplifier to suppress common-mode signals and amplify the received physiological signals. In some embodiments, the analog circuit 630 may include a multi-stage amplifier circuit to amplify the received physiological signals. In some embodiments, the analog circuit 630 may include a filter circuit to filter the received physiological signals. In some embodiments, the analog circuit 630 may include a right leg drive circuit to extract the common-mode signal from the received physiological signals, reverse amplify it, and then feed it back to the signal source, primarily to suppress the power frequency in the signal source. In some embodiments, the analog circuit 630 may include a differential amplifier, a multi-stage amplifier, a filter circuit, and a right leg drive circuit simultaneously, or may include only one or more of these.

[0092] As described above, the control circuit 640 is used to receive physiological signals processed by the analog circuit and sample the processed physiological signals. In some embodiments, the control circuit 640 includes multiple ADC channels, each of which can be used to convert the received physiological signals processed by the analog circuit 630 into digital signals for reading and processing. For example, the first acquisition circuit 611 and the second acquisition circuit 612 can include different input impedances, and the physiological signals they collect can include motion artifact signals in different proportions. The control circuit 640 can identify the physiological signals based on the different proportions of motion artifact signals and obtain the target physiological signal (i.e., pure physiological signal). In some embodiments, the control circuit 640 can also be connected to a display device to display the read digital signal, thereby intuitively reflecting the situation of the physiological signal. In some embodiments, based on the sampling, the control circuit 640 can read, store, process and analyze the physiological signals. Optionally, the control circuit 640 can also issue corresponding instructions based on the sampled data.

[0093] It should be noted that the processing circuit 600 shown in FIG6 is for illustrative purposes only. In some embodiments, the processing circuit 600 may include one or more other components, or one or more components in the processing circuit may be combined or omitted. In some embodiments, the number, position, etc. of one or more components in the processing circuit 600 may vary, and this specification does not limit this.

[0094] Figure 7 is an electrocardiogram containing motion artifacts caused by relative displacement of horizontal movements according to some embodiments of the present specification; Figure 8 is an electrocardiogram containing motion artifacts caused by relative displacement of vertical movements according to some embodiments of the present specification; Figure 9 is an electrocardiogram containing motion artifacts caused by pressing according to some embodiments of the present specification.

[0095] To compare the differences in ECG signals (i.e., physiological signals read in time-sharing) measured between a circuit with a large input impedance and a circuit with a small input impedance (taking 10 kΩ as an example), Figures 7, 8, and 9 (applicable to all Figures 7, 8, and 9, where the glitches in the figures are ECG signals or motion artifact signals, for example, glitches 710, 810, 910, and glitches 710′, 810′, and 910′ correspond to the ECG signals; compared with the glitches corresponding to the ECG signals, the peaks / troughs represented by the glitches corresponding to the motion artifact signals have larger amplitudes, such as glitches 720, 820, 920, and glitches 720′, 820′, and 920′; for an explanation of the glitches, see Figure 4 and its related description) respectively attempted test comparisons for three artificial motion artifact sources: horizontal relative displacement, vertical relative displacement, and pressure. For Figures 7, 7, and 9, the upper figure shows the ECG signal measured by the circuit with a large input impedance, and the lower figure shows the ECG signal measured by the circuit with a small input impedance. Based on Figures 7, 7, and 9, it can be concluded that the circuit with a small input impedance can more clearly detect the corresponding motion artifact signal than the circuit with a large input impedance.

[0096] Figure 10A is a schematic diagram of a processing circuit of a signal processing system according to some embodiments of this specification. Figure 10B is a schematic diagram of a processing circuit of a signal processing system according to some embodiments of this specification. Figure 10C is a schematic diagram of a processing circuit of a signal processing system according to some embodiments of this specification.

[0097] In some embodiments, the processing circuit may include a switch and two signal processing sub-circuits, wherein the switch is used to control the electrode to be connected to one of the two signal processing sub-circuits and disconnected from the other signal processing sub-circuit in one of the different time periods, wherein the two signal processing sub-circuits have different input impedances.

[0098] As shown in FIG10A , the electrode module 1010 includes two electrodes (a first electrode 1011 and a second electrode 1012), and the electrode module 1010 is connected to two signal processing sub-circuits via a switch 1020. For example, the switch 1020 may include at least one set of input ports and at least two sets of output ports (e.g., a first set of output ports 1031 and a second set of output ports 1032). The switch 1020 is connected to the electrode module 1010 via one set of input ports (e.g., including two input ports) and is connected to the two signal processing sub-circuits via two sets of output ports. The input impedances (R4 and R5) of the two signal processing sub-circuits (the sub-circuit where R4 is located is referred to as the first sub-circuit 1041, and the sub-circuit where R5 is located is referred to as the second sub-circuit 1042) are different. The two sub-circuits are respectively connected to the switch 1020 to control the disconnection / connection between the electrode module 1010 and one of the sub-circuits. The switch 1020 comprises a time-division multiplexing switch that can be used to control the opening / closing of a set of output ports of the switch 1020 during one of the different time periods, thereby controlling the connection of the electrode to one of the two signal processing sub-circuits and disconnection from the other signal processing sub-circuit. For example, during the first time period, the switch 1020 controls the first set of output ports 1031 to be disconnected and the second set of output ports 1032 to be closed. At this time, the electrode module 1010 is connected to the second sub-circuit 1042, and the input impedance is R5. For another example, during the second time period, the controller controls the second set of output ports 1032 to be disconnected and the first set of output ports 1031 to be closed. At this time, the electrode module 1010 is connected to the first sub-circuit 1041, and the input impedance is R4. It should be noted that the circuit diagram shown in FIG10A is for illustrative purposes only. In some embodiments, such as shown in FIG10B, a set of input and / or output ports of the switch 1020 can be represented by a single line, and this specification does not limit this. In some embodiments, as shown in FIG10C , switch 1020 may also be provided at the reference ground connection of a signal processing circuit (e.g., the first sub-circuit 1041 and the second sub-circuit 1042) to time-share control the disconnection / connection between the electrode module 1010 and one of the sub-circuits. Furthermore, in conjunction with FIG10A , the input impedance described herein may refer to the impedance between the input terminal of the processing circuit (e.g., the first sub-circuit 1041 or the second sub-circuit 1042) and the reference ground.

[0099] In some embodiments, the ratio of the input impedances of the two signal processing sub-circuits (ie, the ratio of the impedance of R4 to the impedance of R5 ) is not less than 10.

[0100] In some embodiments, each of the two signal processing sub-circuits may include a differential amplifier for differentially amplifying the signals collected by the electrodes.

[0101] A differential amplifier is an electronic device that can amplify the difference between the voltages of two input terminals with a fixed gain. It can be used to amplify the difference in signals collected by electrodes, increase the collected signal output value, and achieve signal enhancement.

[0102] In some embodiments of this specification, the processing circuit acquires signals consistently from the same set of electrodes, employing time-division multiplexing to simultaneously acquire signals from the same set of electrodes using different input impedances. This configuration avoids acquisition errors caused by connecting different sets of electrodes using different impedances, thereby improving measurement accuracy. Furthermore, by incorporating a differential amplifier into the circuit, the acquired signal can be enhanced, facilitating subsequent signal analysis and calculations.

[0103] FIG. 11 is a circuit diagram of another processing circuit of a signal processing system according to some embodiments of this specification.

[0104] In some embodiments, the processing circuit may include a switch and a resistor connected in parallel with the input terminal, and the switch controls whether the resistor is connected in parallel with or disconnected from the input terminal in different time periods.

[0105] As shown in Figure 11, the electrode module 1110 includes two electrodes (a first electrode 1111 and a second electrode 1112), and the electrode module 1110 is connected to the third sub-circuit 1141, wherein the third sub-circuit 1141 is a sub-circuit that only includes the input impedance R6. For example, the first electrode 1111 and the second electrode 1112 can be respectively connected to the two input ports of the third sub-circuit 1141. Furthermore, the processing circuit also includes a switch 1120 and a resistor R7, and the resistor R7 is connected in series with the switch 1120. The switch 1120 is used to control whether the resistor R7 forms a parallel circuit with the input impedance R6. For example, when switch 1120 is open, input impedance R6 is not connected in parallel with resistor R7, and the processing circuit actually uses the third sub-circuit 1141 to collect signals. When switch 1120 is closed, resistor R7 is connected in parallel with the input end of the third sub-circuit 1141 (or with input impedance R6), and the processing circuit actually uses the fourth sub-circuit 1142 to collect signals, wherein the fourth sub-circuit 1142 is a sub-circuit formed by the input impedance R6 and resistor R7 in parallel. Switch 1120 may include a time-division multiplexing switch that can be used to: control the disconnection / connection of the processing circuit and resistor R7 in one of the different time periods, thereby controlling the connection of the electrode to one of the two signal processing sub-circuits. For example, in the first time period, switch 1120 is open, and the processing circuit actually uses the third sub-circuit 1141 to collect signals. For another example, in the second time period, switch 1120 is closed, and the processing circuit actually uses the fourth sub-circuit 1142 to collect signals, and the actual input impedance of the processing circuit is the parallel impedance of R6 and R7. It is understood that in this embodiment, the third sub-circuit 1141 and the fourth sub-circuit 1142 may share some circuitry. In some embodiments, the switch 1120 may also be disposed at the reference ground connection of the processing circuit (e.g., the third sub-circuit 1141) to adjust the input impedance of the processing circuit in a time-sharing manner.

[0106] In some embodiments, the ratio of the input impedance of the processing circuit to the resistance in the switch-off state is not less than 10. In the circuit structure shown in FIG11 , for example, R6 can be not less than 1 MΩ, and R7 can be not greater than 100 KΩ (based on this, when the switch of the processing circuit is off, the input impedance is R6; when the switch of the processing circuit is closed, resistors R7 and R6 are connected in parallel, and the input impedance of the circuit is the total parallel impedance (because the total parallel impedance is less than the impedance of any branch, the total parallel impedance is less than 100 KΩ). Therefore, the ratio of the input impedance of the processing circuit in the switch-off state to the resistance is not less than 10. This can ensure that the ratio of the input impedance of the processing circuit in the switch-off state to the input impedance in the switch-closed state is not less than 10, thereby achieving the circuit design purpose of collecting physiological signals based on a large input impedance and collecting motion artifact signals based on a small input impedance.

[0107] In some embodiments of this specification, the aforementioned circuit structure enables the ECG signal to be fully captured by the circuit when the input impedance is high, while the ECG signal is correspondingly reduced and the motion artifact signal is enhanced when the input impedance is low, thereby improving subsequent recognition accuracy. Furthermore, the aforementioned circuit structure design can simplify the circuit structure and reduce the number of electronic components, thereby facilitating manufacturing and reducing costs.

[0108] In some embodiments of this specification, the processing circuit acquires signals consistently from the same set of electrodes, employing time-division multiplexing to simultaneously acquire signals from the same set of electrodes using different input impedances. This arrangement ensures that the acquired signals all originate from the same set of electrodes, resulting in better signal consistency and lower acquisition errors, thereby improving measurement accuracy. Furthermore, the use of a switch to disconnect or connect parallel resistors can simplify the circuit.

[0109] FIG. 12 is a circuit diagram of a processing circuit of another signal processing system according to some embodiments of this specification.

[0110] In some embodiments, the signal processing system may include: two groups of electrodes (such as electrode group 1210 and electrode group 1220 in Figure 12), each group of electrodes in the two groups of electrodes is used to fit the human body to collect physiological signals; a processing circuit is used to read the physiological signals collected by each group of electrodes respectively, wherein the processing circuit has different input impedances when reading the physiological signals collected by different groups of electrodes, and the physiological signals collected by different groups of electrodes read by the processing circuit contain motion artifact signals in different proportions, and the processing circuit identifies the physiological signals based on the motion artifact signals in different proportions.

[0111] In some embodiments, the processing circuit includes two sub-processing circuits, each connected to one of the two groups of electrodes, wherein the two sub-processing circuits have different input impedances. As shown in the processing circuit of Figure 12, electrode group 1210 includes two electrodes (a first electrode 1211 and a second electrode 1212), and electrode group 1220 includes two electrodes (a third electrode 1221 and a fourth electrode 1222); electrode group 1210 is connected to sub-processing circuit 1230, and electrode group 1220 is connected to sub-processing circuit 1240, wherein the input impedance of sub-processing circuit 1230 is R8, and the input impedance of sub-processing circuit 1240 is R9. Sub-processing circuit 1230 and sub-processing circuit 1240 can respectively collect signals from electrode groups 1210 and 1220 for subsequent processing.

[0112] In some embodiments, such as the processing circuit shown in FIG12 , the ratio of the larger input impedance (e.g., R8) to the smaller input impedance (e.g., R9) among the different input impedances is not less than 10. For example, the ratio of input impedance R8 to input impedance R9 is 20.

[0113] In some embodiments, for the processing circuit shown in FIG12 , the larger input impedance (e.g., R8 ) among the different input impedances is no less than 1 MΩ, and the smaller input impedance (e.g., R9 ) is no greater than 100 KΩ. For example, input impedance R8 is 2 MΩ, and input impedance R9 is 10 KΩ.

[0114] In some embodiments, in some embodiments, the processing circuit can filter out the motion artifact signal and / or enhance the pure physiological signal based on the correspondence between the motion artifact signal and the physiological signal at different ratios, and use the processed physiological signal as the target physiological signal. For example, the processing circuit can identify the motion artifact signal based on the physiological signal read by the low impedance circuit, and then treat the signal with a high correlation with the motion artifact signal as the motion artifact signal from the physiological signal read by the high impedance circuit and filter it out. As an example only, when motion artifacts are caused by factors such as movement (such as running, jumping, etc.), the physiological signal read at low input impedance may show obvious fluctuations (as shown in range A in Figure 6). The processing circuit can identify the signal with obvious fluctuations and use it as the motion artifact signal. Further, the processing circuit can determine the correspondence between the physiological signal read at high input impedance and the motion artifact signal, filter out the motion artifact signal, and / or enhance the pure physiological signal, and use the processed physiological signal as the target physiological signal.

[0115] As shown in the processing circuit of Figure 12, when two measurement circuits (such as sub-processing circuit 1230 and sub-processing circuit 1240) are connected to each other without using a time-division multiplexing scheme, the motion artifact signals measured by the two groups of electrodes (such as electrode groups 1210 and 1220) are required to be as identical as possible. Therefore, the consistency of the two groups of electrodes is required to be high. For example, the distance between the two groups of electrodes is close enough, and the fitting state is similar enough, so that the motion artifact signal collected when using a small impedance can be used to characterize the motion artifact signal in the physiological signal collected when using a large impedance, thereby achieving the filtering of the motion artifact signal. Therefore, it is necessary to limit the distance between the two electrodes of different electrode modules. Each electrode module includes two electrodes. In order to improve the consistency of the motion artifact signal collected using a small impedance and the motion artifact signal in the physiological signal collected when using a large impedance, as shown in Figure 12, when the two groups of electrodes are adjacent to each other, the minimum distance between the two electrodes of different groups is less than the distance threshold. The minimum distance can refer to the distance between the two electrodes closest to each other in different groups of electrodes (for example, the distance between the midpoints of the two closest edges, the average distance between multiple points on the two closest edges, etc.). The distance threshold can be preset, for example, the minimum distance between two electrodes of different groups can be less than 5 cm; for another example, the minimum distance between two electrodes of different groups can be less than 3 cm; for another example, the minimum distance between two electrodes of different groups can be less than 1 cm. In some embodiments, the arrangement of the two groups of electrodes may not be limited to the adjacent arrangement shown in Figure 12. For example, the four electrodes in the two groups of electrodes can be arranged in parallel, and the two electrodes in one group of electrodes are respectively located on both sides of the other group of electrodes. In other words, one group of electrodes can surround the other group of electrodes, and the two groups of electrodes can partially overlap. For example, the center (for example, the centroid) of one group of electrodes overlaps or approximately overlaps with the center of the other group of electrodes. For example, the distance between the center of one group of electrodes and the center of the other group of electrodes can be less than 5 cm; for another example, the distance between the center of one group of electrodes and the center of the other group of electrodes can be less than 3 cm; for another example, the distance between the center of one group of electrodes and the center of the other group of electrodes can be less than 1 cm.

[0116] FIG13 is an exemplary flowchart of a signal processing method according to some embodiments of this specification.

[0117] Step 1310: Physiological signals are collected through electrodes that fit the human body. For an explanation of the electrodes and physiological signals, please refer to FIG. 2 and its related description.

[0118] In step 1320, the processing circuit reads the physiological signal in a time-sharing manner. The processing circuit has different input impedances in different time periods, and the physiological signals read by the processing circuit in different time periods contain different proportions of motion artifact signals. The processing circuit identifies the physiological signal based on the different proportions of motion artifact signals. For detailed descriptions of reading physiological signals, see Figures 2, 10A, 10B, and 11 and their related descriptions.

[0119] In some embodiments, the different input impedances include two input impedances, and a ratio of a larger input impedance to a smaller input impedance of the two input impedances is not less than 10.

[0120] In some embodiments, the larger input impedance of the two input impedances is not less than 1 MΩ, and the smaller input impedance is not greater than 100 KΩ. For example, the larger input impedance is 2 MΩ, and the smaller input impedance is 10 KΩ.

[0121] In some embodiments, during one of the different time periods, a switch controls the electrode to connect to one of two signal processing subcircuits and disconnect from the other signal processing subcircuit, wherein the two signal processing subcircuits have different input impedances. For more details, see Figures 10A and 10B and their related descriptions.

[0122] In some embodiments, each of the two signal processing sub-circuits may further include a differential amplifier, and the differential amplifier is used to perform differential amplification on the signals collected by the electrodes.

[0123] In some embodiments, the processing circuit includes a switch and a resistor connected in parallel with the input terminal, and the switch controls the resistor to be connected in parallel or disconnected with the input terminal in different time periods. For more details, see FIG11 and its related description.

[0124] In some embodiments, a ratio between an input impedance and a resistance of the processing circuit in an off-state of the switch is not less than 10.

[0125] In some embodiments, the processing circuit can filter out the motion artifact signal and / or enhance the pure physiological signal based on the correspondence between the motion artifact signal and the physiological signal at different ratios, and use the processed physiological signal as the target physiological signal. For example, the processing circuit can identify the motion artifact signal based on the physiological signal read by the low impedance circuit, and then treat the signal with a high correlation with the motion artifact signal from the physiological signal read by the high impedance circuit as the motion artifact signal and filter it out. As an example only, when motion artifacts are caused by factors such as movement (such as running, jumping, etc.), the physiological signal read at low input impedance may show obvious fluctuations (as shown in range A in Figure 6). The processing circuit can identify the signal with obvious fluctuations and use it as the motion artifact signal. Furthermore, the processing circuit can determine the correspondence between the physiological signal read at high input impedance and the motion artifact signal, filter out the motion artifact signal, and / or enhance the pure physiological signal, and use the processed physiological signal as the target physiological signal.

[0126] FIG14 is an exemplary flowchart of another signal processing method according to some embodiments of this specification.

[0127] Step 1410: Acquire physiological signals through each of the two sets of electrodes that are in contact with the human body. Detailed description of this method for acquiring physiological signals can be found in FIG. 2 , FIG. 12 and their related descriptions.

[0128] In step 1420, the processing circuit reads the physiological signals collected by each electrode group separately. The processing circuit has different input impedances when reading the physiological signals collected by different electrode groups. The physiological signals collected by the different electrode groups read by the processing circuit contain different proportions of motion artifact signals. The processing circuit identifies the physiological signals based on the different proportions of motion artifact signals. For more details on the processing circuit used in this step, see FIG12 and its related description.

[0129] In some embodiments, each electrode group includes two electrodes, and the minimum distance between two electrodes from different groups is less than a distance threshold. The distance threshold can be preset. For example, the two electrode groups can be adjacent to each other, and the minimum distance between two electrodes from different groups can be less than 5 cm, 3 cm, 1 cm, etc. For another example, one electrode from the two electrode groups can surround the other electrode group, and the distance between the center of one electrode group and the center of the other electrode group can be less than 5 cm, 3 cm, 1 cm, etc.

[0130] In some embodiments, a ratio of a larger input impedance to a smaller input impedance among different input impedances is not less than 10.

[0131] In some embodiments, the larger input impedance among the different input impedances is not less than 1 MΩ, and the smaller input impedance is not greater than 100 KΩ. For example, the larger input impedance is 2 MΩ, and the smaller input impedance is 10 KΩ.

[0132] In some embodiments, the processing circuit includes two sub-processing circuits, each connected to one of the two groups of electrodes, wherein the two sub-processing circuits have different input impedances. For more details about the processing circuit, see FIG12 and its related description.

[0133] In some embodiments, the processing circuit can filter out the motion artifact signal and / or enhance the pure physiological signal based on the correspondence between the motion artifact signal and the physiological signal at different ratios, and use the processed physiological signal as the target physiological signal. For example, the processing circuit can identify the motion artifact signal based on the physiological signal read by the low impedance circuit, and then treat the signal with a high correlation with the motion artifact signal from the physiological signal read by the high impedance circuit as the motion artifact signal and filter it out. As an example only, when motion artifacts are caused by factors such as movement (such as running, jumping, etc.), the physiological signal read at low input impedance may show obvious fluctuations (as shown in range A in Figure 6). The processing circuit can identify the signal with obvious fluctuations and use it as the motion artifact signal. Furthermore, the processing circuit can determine the correspondence between the physiological signal read at high input impedance and the motion artifact signal, filter out the motion artifact signal, and / or enhance the pure physiological signal, and use the processed physiological signal as the target physiological signal.

[0134] While the basic concepts have been described above, it will be apparent to those skilled in the art that the detailed disclosure is merely illustrative and does not limit this specification. Although not explicitly stated herein, various modifications, improvements, and revisions to this specification may be made by those skilled in the art. Such modifications, improvements, and revisions are suggested in this specification and remain within the spirit and scope of the exemplary embodiments of this specification.

[0135] This specification also uses specific terms to describe the embodiments of this specification. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "one embodiment," "an embodiment," or "an alternative embodiment" two or more times in different locations in this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of this specification may be appropriately combined.

[0136] In addition, unless expressly stated in the claims, the order of the processing elements and sequences, the use of alphanumeric characters, or the use of other names described in this specification are not intended to limit the order of the processes and methods of this specification. Although the above disclosure discusses some of the invention embodiments currently considered useful through various examples, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the spirit and scope of the embodiments of this specification. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

[0137] Similarly, it should be noted that, in order to simplify the presentation of this specification and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this specification sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not imply that the subject matter of this specification requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single disclosed embodiment.

[0138] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of this specification are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

[0139] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, and documents, cited in this specification is hereby incorporated by reference in its entirety. This includes application history documents that are inconsistent with or conflict with the content of this specification, as well as documents (currently or subsequently attached to this specification) that limit the broadest scope of the claims of this specification. It should be noted that if the descriptions, definitions, and / or terminology used in the accompanying materials are inconsistent or conflicting with the content of this specification, the descriptions, definitions, and / or terminology used in this specification will control.

[0140] Finally, it should be understood that the embodiments described in this specification are intended only to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, by way of example and not limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly described and illustrated in this specification.

Claims

1. A signal processing system, characterized in that: include: Electrodes, which are used to fit the human body to collect physiological signals; as well as A processing circuit is used to read the physiological signal in time division, wherein the processing circuit has different input impedances in different time periods, the physiological signal read by the processing circuit contains motion artifact signals of different proportions, and the processing circuit identifies the physiological signal based on the motion artifact signals of different proportions.

2. The signal processing system according to claim 1, characterized in that The different input impedances include at least two input impedances, and a ratio of a larger input impedance to a smaller input impedance of the at least two input impedances is not less than 10.

3. The signal processing system according to claim 2, characterized in that The larger input impedance of the at least two input impedances is not less than 1 MΩ, and the smaller input impedance is not greater than 100 KΩ.

4. The signal processing system according to claim 1, characterized in that The processing circuit includes a switch and at least two signal processing sub-circuits. In one of the different time periods, the switch is used to control the electrode to be connected to one of the at least two signal processing sub-circuits and disconnected from the other signal processing sub-circuit, wherein the at least two signal processing sub-circuits have different input impedances.

5. The signal processing system according to claim 4, characterized in that Each of the at least two signal processing subcircuits comprises a differential amplifier for differentially amplifying the signals collected by the electrodes.

6. The signal processing system according to claim 1, characterized in that The processing circuit includes a switch and a resistor connected in parallel with the input terminal, and the switch controls the resistor to be connected in parallel or disconnected with the input terminal in different time periods.

7. The signal processing system according to claim 6, characterized in that The ratio of the input impedance of the processing circuit to the resistor when the switch is in an off state is not less than 10.

8. The signal processing system according to claim 1, characterized in that: The processing circuit identifying the physiological signal based on the motion artifact signals of different proportions comprises: Based on the correspondence between the physiological signals containing the motion artifact signals in different proportions, the motion artifact signals are filtered out and / or the pure physiological signals are enhanced, and the physiological signals obtained by the processing are used as target physiological signals.

9. A signal processing system, characterized in that: include: Two groups of electrodes, each group of electrodes in the two groups of electrodes is used to fit the human body to collect physiological signals; as well as A processing circuit is used to read the physiological signals collected by each group of electrodes respectively, wherein the processing circuit has different input impedances when reading the physiological signals collected by different groups of electrodes, the physiological signals collected by the different groups of electrodes read by the processing circuit contain motion artifact signals of different proportions, and the processing circuit identifies the physiological signals based on the motion artifact signals of different proportions.

10. The signal processing system according to claim 9, characterized in that: Each group of electrodes includes two electrodes, and the minimum distance between two electrodes in different groups is less than 5 cm.

11. The signal processing system according to claim 9, characterized in that: The ratio of the larger input impedance to the smaller input impedance among the different input impedances is not less than 10.

12. The signal processing system according to claim 11, characterized in that: Among the different input impedances, the larger input impedance is not less than 1 MΩ, and the smaller input impedance is not greater than 100 KΩ.

13. The signal processing system according to claim 9, characterized in that: The processing circuit includes at least two sub-processing circuits, which are respectively connected to one group of electrodes in the two groups of electrodes, wherein the at least two sub-processing circuits have different input impedances.

14. The signal processing system according to claim 9, characterized in that: The processing circuit identifying the physiological signal based on the motion artifact signals of different proportions comprises: Based on the correspondence between the physiological signals containing the motion artifact signals in different proportions, the motion artifact signals are filtered out and / or the pure physiological signals are enhanced, and the physiological signals obtained by the processing are used as target physiological signals.

15. A signal processing method, characterized in that: include: Physiological signals are collected through electrodes that fit the human body; as well as The physiological signal is read in time-sharing manner by a processing circuit, wherein the processing circuit has different input impedances in different time periods, the physiological signal read by the processing circuit contains motion artifact signals of different proportions, and the processing circuit identifies the physiological signal based on the motion artifact signals of different proportions.

16. The signal processing system according to claim 15, characterized in that: The different input impedances include at least two input impedances, and a ratio of a larger input impedance to a smaller input impedance of the at least two input impedances is not less than 10.

17. The signal processing method according to claim 16, characterized in that: The larger input impedance of the at least two input impedances is not less than 1 MΩ, and the smaller input impedance is not greater than 100 KΩ.

18. The signal processing method according to claim 15, characterized in that: The processing circuit includes a switch and at least two signal processing sub-circuits, and the method includes: In one of the different time periods, the switch controls the electrode to be connected to one of the at least two signal processing subcircuits and disconnected from the other signal processing subcircuit, wherein the at least two signal processing subcircuits have different input impedances.

19. The signal processing method according to claim 18, characterized in that: Each of the at least two signal processing subcircuits comprises a differential amplifier, and the method comprises: The signals collected by the electrodes are differentially amplified by the differential amplifier.

20. The signal processing method according to claim 15, characterized in that: The processing circuit includes a switch and a resistor connected in parallel with an input terminal, and the method includes: The switch is used to control the resistor to be connected in parallel or disconnected from the input terminal in different time periods.

21. The signal processing method according to claim 20, characterized in that: A ratio between an input impedance of the processing circuit and the resistor when the switch is in an off state is not less than 10.

22. The signal processing method according to claim 15, characterized in that: The processing circuit identifying the physiological signal based on the motion artifact signals of different proportions comprises: Based on the correspondence between the physiological signals containing the motion artifact signals in different proportions, the motion artifact signals are filtered out and / or the pure physiological signals are enhanced, and the physiological signals obtained by the processing are used as target physiological signals.

23. A signal processing method, characterized in that: include: Physiological signals are collected by each of two sets of electrodes that fit the human body; as well as The physiological signals collected by each group of electrodes are read separately by the processing circuit, wherein the processing circuit has different input impedances when reading the physiological signals collected by different groups of electrodes, the physiological signals collected by the different groups of electrodes read by the processing circuit contain motion artifact signals of different proportions, and the processing circuit identifies the physiological signals based on the motion artifact signals of different proportions.

24. The signal processing method according to claim 23, characterized in that: Each group of electrodes includes two electrodes, and the minimum distance between two electrodes in different groups is less than 5 cm.

25. The signal processing method according to claim 23, characterized in that: The ratio of the larger input impedance to the smaller input impedance among the different input impedances is not less than 10.

26. The signal processing method according to claim 25, characterized in that: Among the different input impedances, the larger input impedance is not less than 1 MΩ, and the smaller input impedance is not greater than 100 KΩ.

27. The signal processing method according to claim 23, characterized in that: The processing circuit includes at least two sub-processing circuits, which are respectively connected to one group of electrodes in the two groups of electrodes, wherein the at least two sub-processing circuits have different input impedances.

28. The signal processing method according to claim 23, characterized in that: The processing circuit identifying the physiological signal based on the motion artifact signals of different proportions comprises: Based on the correspondence between the physiological signals containing the motion artifact signals in different proportions, the motion artifact signals are filtered out and / or the pure physiological signals are enhanced, and the physiological signals obtained by the processing are used as target physiological signals.

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