Filter circuit based on PPG signal and ECG signal and intelligent wearable device

Abstract

The utility model provides a filter circuit based on PPG signals and ECG signals and an intelligent wearable device. The filter circuit comprises a signal input end, a signal output end, a band-pass filter module and a band-stop filter module. The band-pass filtering module and the band-stop filtering module are electrically connected in series to a circuit formed by the signal input end and the signal output end; the signal input end is used for receiving a to-be-filtered signal, and the to-be-filtered signal comprises a PPG signal and / or an ECG signal; the band-pass filtering module is used for enabling a frequency band belonging to the PPG signal and the ECG signal in the to-be-filtered signal to pass through; the band elimination filtering module is used for blocking an interference frequency band where an interference signal is located in the ECG signal, and the interference frequency band and a frequency band where the PPG signal is located are not overlapped. According to the utility model, the filtering quality of PPG signals and ECG signals can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to biological data detection circuit technical field especially, it relates to a filter circuit and intelligent wear equipment based on PPG signal and ECG signal. BACKGROUND

[0002] Now people's life rhythm accelerates, and work is busy, and many people sit for a long time in office, and long sitting leads to the generation of many diseases, along with the rapid development of intelligent wear equipment, many health monitoring algorithms are applied to the intelligent wear equipment to monitor people's health.

[0003] But the existing intelligent wear equipment cannot flexibly and high quality filter PPG (Photoplethsmography, photoelectric plethysmogram) signal and ECG (Electrocardiogram, electrocardiogram) signal. UTILITY MODEL CONTENT

[0004] To solve the above problems, the filter circuit and intelligent wear equipment based on PPG signal and ECG signal provided by the utility model can improve the quality of filtering PPG signal and ECG signal by setting band pass filter module and band stop filter module.

[0005] Firstly, the utility model provides a filter circuit based on PPG signal and ECG signal, and the filter circuit includes signal input end, signal output end, band pass filter module and band stop filter module.

[0006] Band pass filter module and band stop filter module are connected in series on the circuit formed by signal input end and signal output end.

[0007] Signal input end is used to receive the signal to be filtered, and the signal to be filtered includes PPG signal and / or ECG signal; band pass filter module is used to let the frequency band belonging to PPG signal and ECG signal in the signal to be filtered pass; band stop filter module is used to block the interference frequency band of interference signal in ECG signal, and the interference frequency band and the frequency band of PPG signal do not overlap each other.

[0008] Optionally, band pass filter module includes adjustable resistance unit, adjustable capacitance unit and first amplifier.

[0009] Adjustable resistance unit and adjustable capacitance unit are connected in series between the input end of first amplifier and signal input end.

[0010] Optionally, first IIC port is arranged on adjustable resistance unit.

[0011] Optionally, the band-pass filter module further comprises an external pull-up resistor, one end of the external pull-up resistor is connected with the first IIC port, and the other end of the external pull-up resistor is electrically connected with the power supply end.

[0012] Optionally, the filter circuit further comprises a regulation module, the regulation module is electrically connected with the first IIC port.

[0013] The regulation module adjusts the resistance of the adjustable resistance unit through the first IIC port.

[0014] Optionally, the adjustable capacitance unit is provided with a second IIC port.

[0015] The adjustable capacitance unit is electrically connected with the regulation module through the second IIC port, and the regulation module adjusts the capacitance of the adjustable capacitance unit through the second IIC port.

[0016] Optionally, the band-pass filter module further comprises a first resistor, a first capacitor, a second resistor, a third resistor and a fourth resistor.

[0017] One end of the first resistor is electrically connected with the signal input end, and the other end of the first resistor is electrically connected with one end of the first capacitor, one end of the fourth resistor and one end of the adjustable capacitance unit, respectively.

[0018] One end of the second resistor is grounded, and the other end of the second resistor is electrically connected with the other input end of the first amplifier.

[0019] One end of the third resistor is electrically connected with the other end of the second resistor, and the other end of the third resistor is electrically connected with the output end of the first amplifier.

[0020] The other end of the fourth resistor is electrically connected with the output end of the first amplifier, and the other end of the first capacitor is grounded.

[0021] Optionally, the band-stop filter module comprises a second capacitor, a third capacitor, a fourth capacitor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a second amplifier.

[0022] One end of the second capacitor and one end of the fifth resistor are both electrically connected with the output end of the first amplifier, the other end of the second capacitor is electrically connected with one end of the third capacitor and one end of the seventh resistor, respectively, and the other end of the fifth resistor is electrically connected with one end of the sixth resistor and one end of the fourth capacitor, respectively.

[0023] The other end of the third capacitor and the other end of the sixth resistor are both electrically connected with the input end of the second amplifier.

[0024] The other end of the seventh resistor is electrically connected with the output end of the second amplifier and the signal output end, and the other end of the fourth capacitor is grounded.

[0025] One end of the eighth resistor is grounded, and the other end of the eighth resistor is electrically connected with the other input end of the second amplifier and one end of the ninth resistor respectively, and the other end of the ninth resistor is electrically connected with the output end of the second amplifier.

[0026] Optionally, the resistance value of the adjustable resistance unit is R2, and the capacitance value of the adjustable capacitance unit is C2.

[0027] ω0=2πf0;

[0028]

[0029] Wherein, R1 represents the resistance value of the first resistance; C1 represents the capacitance value of the first capacitance; R3 represents the resistance value of the fourth resistance; R4 represents the resistance value of the second resistance; R5 represents the resistance value of the third resistance; f0 represents the center frequency point of the band-pass filter module; B w represents the bandwidth of the filter circuit; when the to-be-filtered signal comprises an ECG signal, f0=20.25Hz, B w =39.5Hz; when the to-be-filtered signal comprises a PPG signal, f0=2.25Hz, B w =3.5Hz.

[0030] In a second aspect, the utility model provides a kind of intelligent wearable equipment, and the intelligent wearable equipment includes the filter circuit as in any one of the first aspect and sensor, sensor is used to collect PPG signal and / or ECG signal, signal input end is electrically connected with sensor, for receiving PPG signal and / or ECG signal.

[0031] The filter circuit based on PPG signal and ECG signal and the intelligent wearable equipment provided by the utility model embodiment, by connecting in series the band-pass filter module and the band-stop filter module, while retaining the frequency band where PPG signal and ECG signal are located, the interference frequency band where interference signal in ECG signal is located is also removed, so that the filter circuit not only can filter PPG signal and ECG signal, but also improves the quality of filtering PPG signal or ECG signal. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.

[0033] Figure 1 It is a schematic structural diagram of the filter circuit of an embodiment of the present application.

[0034] Figure 2 Schematic partial circuit diagram of a control module according to an embodiment of the application.

[0035] Reference signs:

[0036] 1, signal input end; 2, signal output end; 3, band-pass filter module; R2, adjustable resistance unit; C2, adjustable capacitance unit; U1, first amplifier; R11, external pull-up resistance; R1, first resistance; C1, first capacitance; R4, second resistance; R5, third resistance; R3, fourth resistance; 4, band-stop filter module; C3, second capacitance; C4, third capacitance; C5, fourth capacitance; R6, fifth resistance; R7, sixth resistance; R8, seventh resistance; R9, eighth resistance; R10, ninth resistance; U2, second amplifier. DETAILED DESCRIPTION

[0037] For the purpose of promoting an understanding of the application, the application will now be described in greater detail with reference to the figures. The embodiments of the application are illustrated in the figures. However, the application can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0039] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and / or operation in addition to the orientations depicted in the figures. For example, if a device described is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0040] It should be noted that when an element is referred to as being "fixedly connected" to another element, it can be directly connected to the other element or intervening elements can be present. In contrast, when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected to the other element or intervening elements can be present. Stated differently, when an element is referred to as being "directly on" another element, no intervening elements are present. As used herein the terms "vertical", "horizontal", "left", "right", and similar expressions are used for explanation only.

[0041] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It should also be understood that the term "comprising" or "including" or "having" or the like, as used herein, is specifically intended to mean the presence of stated features, integers, steps, components, parts, or combinations thereof, but not to the exclusion of the presence or addition of one or more other features, integers, steps, components, parts, or combinations thereof.

[0042] It should be noted that an electrocardiogram is a graphical recording of the electrical activity of the heart, measured by placing electrodes on the skin. It can provide detailed information about the health of the heart, commonly used for the diagnosis of heart disease, monitoring of heart function and evaluation of heart rhythm. Photoplethysmogram is a graphical measurement of blood volume changes using optical technology, usually through optical sensors on the skin surface to detect changes in blood flow. PPG signals are widely used in heart rate monitoring, blood oxygen saturation temperature measurement and other parameters related to the circulatory system.

[0043] The PPG signal acquisition process includes first obtaining the original PPG analog signal from the PPG sensor. The original PPG analog signal contains a lot of noise, and by adding a hardware filter circuit in the hardware circuit to process the noise of the PPG analog signal, a high-quality PPG signal can be obtained. The waveform of the PPG signal is obtained by recording the pulsatile state of the blood vessels using a photoelectric sensor; the PPG sensor includes a light source emitter and a photoelectric receiver, and its working principle is that when the light source emitter emits a light beam of a certain wavelength to the skin surface of the finger, the light beam will be transmitted or reflected to the photoelectric receiver.

[0044] In addition, the heart rate of the human body generally jumps at 40-240 BPM / min, and the signal needs to be reserved between 0.5 Hz-4 Hz, and the noise at 0-0.5 Hz and above 4 Hz is removed, so that the quality of the collected PPG signal is better. The frequency of the QRS complex of the ECG is wide, and the effective frequency band is mainly between 0.5 Hz-40 Hz. In order to be compatible with the PPG signal and the ECG signal, the utility model provides a programmable filter circuit with different parameters. The ECG signal contains 50 Hz power frequency interference, and the noise interference is particularly strong, and the low-pass filter cannot remove all the interference, so a 50 Hz band group filter is added to remove the interference noise.

[0045] In a first aspect, an embodiment of the utility model provides a filter circuit based on PPG signal and ECG signal, refer to Figure 1 , the filter circuit includes: signal input end 1, signal output end 2, band-pass filter module 3 and band-stop filter module 4.

[0046] Band-pass filter module 3 and band-stop filter module 4 are connected in series on the circuit formed by signal input end 1 and signal output end 2. Wherein, band-pass filter module 3 can be located in the upstream of band-stop filter module 4, also can be located in the downstream of band-stop filter module 4. In this embodiment, band-pass filter module 3 is located in the upstream of band-stop filter module 4, that is, band-pass filter module 3 is located between band-stop filter module 4 and signal input end 1.

[0047] Signal input end 1 is used for receiving the signal to be filtered, and the signal to be filtered includes PPG signal and / or ECG signal;Band-pass filter module 3 is used for passing the frequency band of PPG signal and ECG signal in the signal to be filtered;Band-stop filter module 4 is used for blocking the interference frequency band of interference signal in ECG signal, and the interference frequency band and the frequency band of PPG signal do not overlap each other.

[0048] The filter circuit based on PPG signal and ECG signal and the intelligent wearable device provided by the utility model embodiment, by connecting band-pass filter module 3 and band-stop filter module 4 in series, the interference frequency band of interference signal in ECG signal is removed while the frequency band of PPG signal and ECG signal is reserved, so that the filter circuit can not only filter PPG signal and ECG signal, but also improve the quality of filtering PPG signal or ECG signal. Wherein, by setting the interference frequency band and the frequency band of PPG signal do not overlap each other, the quality of filtering PPG signal is not affected in the case of improving the quality of filtering ECG signal.

[0049] Further, the band-pass filter module 3 comprises an adjustable resistance unit R2, an adjustable capacitance unit C2 and a first amplifier U1. The adjustable resistance unit R2 and the adjustable capacitance unit C2 are connected in series between the input end of the first amplifier U1 and the signal input end 1.

[0050] It can be understood that the adjustable resistance unit R2 is a unit with adjustable resistance, and the adjustable capacitance unit C2 is a unit with adjustable capacitance. The resistance value of the adjustable resistance unit R2 and the capacitance value of the adjustable capacitance unit C2 can be directly controlled manually or automatically controlled by a control module.

[0051] In this embodiment, the adjustable resistance unit R2 and the adjustable capacitance unit C2 are arranged in the band-pass filter module 3, so that the corresponding capacitance value or / and resistance value in the band-pass filter module 3 can be flexibly adjusted, so that the filter circuit can be applied to filter PPG signals and ECG signals in various environments, thereby improving the compatibility and filtering precision of the filter circuit.

[0052] Further, the adjustable resistance unit R2 is provided with a first IIC port, and the adjustable capacitance unit C2 is provided with a second IIC port. In this embodiment, the number of the first IIC port and the second IIC port is two, and the two first IIC ports are SDA port, i.e. data line port, and SCL port, i.e. clock line port, and the two second IIC ports are arranged in the same way as the two first IIC ports.

[0053] The adjustable resistance unit R2 and the adjustable capacitance unit C2 can be connected to an external control module through the corresponding IIC port, so as to dynamically adjust the resistance value of the adjustable resistance unit R2 and the capacitance value of the adjustable capacitance unit C2 through the external control module.

[0054] In this embodiment, the adjustable resistance unit R2 is a digital resistor with model MCP4018, and the maximum resistance value has six values, i.e. 5kΩ, 10kΩ, 50kΩ and 100kΩ. The maximum value can be set by programming, and each maximum value includes 128 equal parts, and the step length of resistance change corresponding to each maximum value is 39.37Ω, 78.74Ω, 393.7Ω and 787.4Ω in turn. The adjustable capacitance unit C2 is a digital capacitor with model NCD2400M, and the dynamic adjustment of 12.5pF-194pF is realized by programming, but is not limited thereto.

[0055] In addition, the adjustable resistor unit R2 also includes a VDD port, a VSS port, a B port, and a W port. The VDD and VSS ports are connected to the 3.3V power supply and power ground, respectively; the W port is the input terminal of the adjustable resistor unit R2, and the B port is the output terminal of the adjustable resistor unit R2. The W port is connected to one input terminal of the first amplifier U1, and the B port is connected to power ground. The adjustable capacitor unit C2 also includes a VDD port, a GND port, a CP port, and a CN port. The VDD and GND ports are connected to the 3.3V power supply and power ground, respectively; the CP port is the input terminal of the adjustable capacitor unit C2, and the CN port is the output terminal of the adjustable capacitor unit C2. The CP port is connected to one end of the first capacitor C1, and the CN port is connected to one input terminal of the first amplifier U1 and the W port of the adjustable resistor unit R2.

[0056] In this embodiment, the bandpass filter module 3 further includes an external pull-up resistor R11. One end of the external pull-up resistor R11 is connected to the first IIC port, and the other end is electrically connected to the power supply terminal. In this embodiment, the resistance of the external pull-up resistor R11 is 4.8K ohms, and there are two of them, which are electrically connected to the SDA port and SCL port of the adjustable resistor unit R2, respectively. By setting the external pull-up resistor R11, the electromagnetic interference immunity of the filter circuit bus is improved.

[0057] It is understandable that the adjustable resistor unit R2 and the adjustable capacitor unit C2 can be connected together to a control module, or they can be connected to a control module separately. Regardless of which control module is connected, the resistance of the adjustable resistor unit R2 and the capacitance of the adjustable capacitor unit C2 can be controlled using existing devices.

[0058] In this embodiment, the adjustable resistor unit R2 and the adjustable capacitor unit C2 are both connected to a control module. Specifically, the control module is an MCU (Microcontroller Unit), combined with... Figure 2 Its P0-11 and P0-12 ports are electrically connected to the clock line port and data line port on the adjustable capacitor unit C2, respectively. Its P1-08 and P1-09 ports are electrically connected to the clock line port and data line port on the adjustable resistor unit R2, respectively. This embodiment does not specifically limit the working principle of the control module, which can be implemented by existing MCUs.

[0059] In a further optional embodiment of the present embodiment, the filter circuit further comprises a regulation module, the regulation module being connected to the adjustable resistance unit R2 and the adjustable capacitance unit C2 through the first IIC port and the second IIC port respectively. The regulation module is electrically connected to the first IIC port, and adjusts the resistance of the adjustable resistance unit R2 through the first IIC port. The adjustable capacitance unit C2 is electrically connected to the regulation module through the second IIC port, and the regulation module adjusts the capacitance of the adjustable capacitance unit C2 through the second IIC port.

[0060] Further, the band-pass filter module 3 further comprises a first resistance R1, a first capacitance C1, a second resistance R4, a third resistance R5 and a fourth resistance R3.

[0061] One end of the first resistance R1 is electrically connected to the signal input end 1, and the other end of the first resistance R1 is electrically connected to one end of the first capacitance C1, one end of the fourth resistance R3 and the CP port of the adjustable capacitance unit C2 respectively.

[0062] One end of the second resistance R4 is grounded, and the other end of the second resistance R4 is electrically connected to the other input end of the first amplifier U1. One end of the third resistance R5 is electrically connected to the other end of the second resistance R4, and the other end of the third resistance R5 is electrically connected to the output end of the first amplifier U1. The other end of the fourth resistance R3 is electrically connected to the output end of the first amplifier U1, and the other end of the first capacitance C1 is grounded.

[0063] The band-stop filter module 4 comprises a second capacitance C3, a third capacitance C4, a fourth capacitance C5, a fifth resistance R6, a sixth resistance R7, a seventh resistance R8, an eighth resistance R9, a ninth resistance R10 and a second amplifier U2.

[0064] One end of the second capacitance C3 and one end of the fifth resistance R6 are both electrically connected to the output end of the first amplifier U1, and the other end of the second capacitance C3 is electrically connected to one end of the third capacitance C4 and one end of the seventh resistance R8 respectively. The other end of the fifth resistance R6 is electrically connected to one end of the sixth resistance R7 and one end of the fourth capacitance C5 respectively.

[0065] The other end of the third capacitance C4 and the other end of the sixth resistance R7 are both electrically connected to the input end of the second amplifier U2.

[0066] The other end of the seventh resistance R8 is electrically connected to the output end of the second amplifier U2 and the signal output end 2, and the other end of the fourth capacitance C5 is grounded.

[0067] One end of the eighth resistance R9 is grounded, and the other end of the eighth resistance R9 is electrically connected to the other input end of the second amplifier U2 and one end of the ninth resistance R10 respectively. The other end of the ninth resistance R10 is electrically connected to the output end of the second amplifier U2.

[0068] wherein, in the case that the resistance value of the eighth resistor R9 is determined, the resistance value of the ninth resistor R10 is R 10 The calculation formula is as follows:

[0069] fQ’=1.8;

[0070]

[0071] Q’ represents the quality factor of the band-stop filter module;

[0072] wherein, the capacitance value of the second capacitor C3, the capacitance value of the third capacitor C4 satisfy the following relationship, the resistance value of the fifth resistor R6, the resistance value of the sixth resistor R7 satisfy the following relationship:

[0073] f1=50, C3=C4=C, R6=R7=R

[0074] ω1=2π*f1;

[0075]

[0076] C3 represents the capacitance value of the second capacitor C3; C4 represents the capacitance value of the third capacitor C4; R6 represents the resistance value of the fifth resistor R6; R7 represents the resistance value of the sixth resistor R7; f1 represents the center frequency point of the band-stop filter module; C and R can be determined by specific setting under the condition of satisfying the above calculation formula, R8 represents the resistance value of the seventh resistor R8.

[0077] Further, the resistance value of the adjustable resistor unit is R2, and the capacitance value of the adjustable capacitor unit is C2, and the calculation formula is as follows:

[0078] ω0=2πf0;

[0079]

[0080] wherein, R1 represents the resistance value of the first resistor; C1 represents the capacitance value of the first capacitor; R3 represents the resistance value of the fourth resistor; R4 represents the resistance value of the second resistor R4; R5 represents the resistance value of the third resistor R5; f0 represents the center frequency point of the band-pass filter module 3; B w represents the bandwidth of the filter circuit; when the to-be-filtered signal includes an ECG signal, f0=20.25Hz, B w =39.5Hz; when the to-be-filtered signal includes a PPG signal, f0=2.25Hz, B w =3.5Hz.

[0081] After R2 and C2 are calculated, the resistance value of the adjustable resistance unit R2 and the capacitance value of the adjustable capacitance unit C2 can be adjusted to the corresponding values by the adjusting module, so that the filter circuit is suitable for high-quality filtering of the current signal to be filtered.

[0082] The filter circuit structure based on the PPG signal and the ECG signal provided by the embodiment is simple, by arranging the band-pass filter module 3 and the band-stop filter module 4, the frequency band where the ECG signal is located is retained, and the interference frequency band where the interference signal in the ECG signal is removed, so that the filter circuit can not only filter the PPG signal and the ECG signal, but also improve the quality of filtering the PPG signal or the ECG signal, and improve the compatibility of the filter circuit.

[0083] In a second aspect, the utility model provides a kind of intelligent wearable equipment, and the intelligent wearable equipment includes the filter circuit as in any one of the first aspect and sensor, sensor is used to collect PPG signal and / or ECG signal, signal input end is electrically connected with sensor, for receiving PPG signal and / or ECG signal.In the embodiment, the intelligent wearable equipment is smart watch, but is not limited to this.

[0084] In the description of the present specification, the description of the terms "some embodiments", "other embodiments", "ideal embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0085] The technical features of the above embodiments can be combined arbitrarily, and to make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0086] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of variations and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A filtering circuit based on PPG signal and ECG signal, characterized in that, The filter circuit comprises a signal input end, a signal output end, a band-pass filter module and a band-stop filter module; The band-pass filter module and the band-stop filter module are connected in series on the circuit formed by the signal input end and the signal output end; The signal input end is configured to receive a signal to be filtered, and the signal to be filtered comprises a PPG signal and / or an ECG signal; the band-pass filter module is configured to allow the PPG signal and the ECG signal in the signal to be filtered to pass through; and the band-stop filter module is configured to block an interference frequency band of an interference signal in the ECG signal, and the interference frequency band and the frequency band of the PPG signal do not overlap.

2. The filter circuit of claim 1, wherein, The band-pass filter module comprises an adjustable resistance unit, an adjustable capacitance unit and a first amplifier; The adjustable resistance unit and the adjustable capacitance unit are connected in series between the input end of the first amplifier and the signal input end.

3. The filter circuit of claim 2, wherein, A first IIC port is arranged on the adjustable resistance unit.

4. The filter circuit of claim 3, wherein, The band-pass filter module further comprises an external pull-up resistor, one end of the external pull-up resistor is connected with the first IIC port, and the other end of the external pull-up resistor is electrically connected with a power supply end.

5. The filter circuit of claim 3, wherein, The filter circuit further comprises a regulation module, and the regulation module is electrically connected with the first IIC port; The regulation module adjusts the resistance of the adjustable resistance unit through the first IIC port.

6. The filter circuit of claim 5, wherein, A second IIC port is arranged on the adjustable capacitance unit; The adjustable capacitance unit is electrically connected with the regulation module through the second IIC port, and the regulation module adjusts the capacitance of the adjustable capacitance unit through the second IIC port.

7. The filter circuit of claim 2, wherein, The band-pass filter module further comprises a first resistance, a first capacitance, a second resistance, a third resistance and a fourth resistance; One end of the first resistance is electrically connected with the signal input end, and the other end of the first resistance is electrically connected with one end of the first capacitance, one end of the fourth resistance and one end of the adjustable capacitance unit, respectively; One end of the second resistance is grounded, and the other end of the second resistance is electrically connected with the other input end of the first amplifier; One end of the third resistance is electrically connected with the other end of the second resistance, and the other end of the third resistance is electrically connected with the output end of the first amplifier; The other end of the fourth resistance is electrically connected with the output end of the first amplifier, and the other end of the first capacitance is grounded.

8. The filter circuit of claim 2, wherein, The band-stop filter module comprises a second capacitance, a third capacitance, a fourth capacitance, a fifth resistance, a sixth resistance, a seventh resistance, an eighth resistance, a ninth resistance and a second amplifier; One end of the second capacitance and one end of the fifth resistance are both electrically connected with the output end of the first amplifier, the other end of the second capacitance is electrically connected with one end of the third capacitance and one end of the seventh resistance, respectively, and the other end of the fifth resistance is electrically connected with one end of the sixth resistance and one end of the fourth capacitance, respectively; The other end of the third capacitance and the other end of the sixth resistance are both electrically connected with the input end of the second amplifier; The other end of the seventh resistor is electrically connected with the output end of the second amplifier and the signal output end, and the other end of the fourth capacitor is grounded; One end of the eighth resistor is grounded, and the other end of the eighth resistor is electrically connected with the other input end of the second amplifier and one end of the ninth resistor respectively, and the other end of the ninth resistor is electrically connected with the output end of the second amplifier.

9. The filter circuit of claim 2, wherein, The resistance value of the adjustable resistance unit is R2, and the capacitance value of the adjustable capacitance unit is C2; ω0 = 2πf0; Wherein, R1 represents the resistance value of the first resistor; C1 represents the capacitance value of the first capacitor; R3 represents the resistance value of the fourth resistor; R4 represents the resistance value of the second resistor; R5 represents the resistance value of the third resistor; f0 represents the center frequency point of the band-pass filter module; B w represents the bandwidth of the filter circuit; when the signal to be filtered comprises an ECG signal, f0=20.25 Hz, B w =39.5 Hz; when the signal to be filtered comprises a PPG signal, f0=2.25 Hz, B w =3.5 Hz.

10. A smart wearable device, characterized by, The smart wearable device comprises the filtering circuit according to any one of claims 1 to 9 and a sensor for collecting the PPG signal and / or the ECG signal, and the signal input end is electrically connected with the sensor for receiving the PPG signal and / or the ECG signal.

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