TWI495451B - Non-contact vital sign sensing system and sensing method using the same - Google Patents

Description

Non-contact physiological signal sensing system and sensing method thereof

The disclosure relates to a non-contact physiological signal sensing system and a sensing method thereof.

In recent years, with the improvement of material life, people are more concerned about health. Because most people tend to ignore the warnings issued by the body. Therefore, a variety of physiological signal measuring devices are currently available to monitor the physiological signals of the subject to detect their health.

There are currently contact physiological signal sensing systems and non-contact physiological signal sensing systems. The contact physiological signal sensing system measures by touching the human body, and the circuit composition thereof is simple, but if used for a long time, the subject may be uncomfortable.

Compared with the contact physiological signal sensing system, the non-contact physiological signal sensing system can reduce the discomfort of the subject during the sensing process, and is also free from the limitation of the site, so it can be applied to medical care or physiological monitoring. on.

Therefore, the present invention proposes a non-contact physiological signal sensing system that counteracts the subject's body movement interference during sensing.

The disclosed embodiments relate to a non-contact physiological signal sensing system that utilizes a self-injection locking phenomenon to detect physiological signals and utilizes mutual injection locking to offset body movement interference.

According to an exemplary embodiment of the present disclosure, a non-contact physiological signal sensing system is provided, including: a physiological signal sensing module and at least one body movement interference cancellation module. The physiological signal sensing module senses one of the subjects The physiological signal includes: a first antenna transmitting a first transmitted wireless signal to the subject, and receiving a first reflected wireless signal reflected by the subject; a first voltage controlled oscillator directly Connected to the first antenna, output the first transmit wireless signal to the first antenna, and receive the first reflected wireless signal via the first antenna, so that the physiological signal sensing module is in a self Injection locking; a frequency demodulating unit coupled to the first voltage controlled oscillator to demodulate a frequency change of the first voltage controlled oscillator; and a signal processing unit coupled to the frequency demodulating unit and the first The voltage controlled oscillator analyzes the physiological signal of the subject according to the frequency change of the first voltage controlled oscillator, and determines a first oscillation frequency of the first voltage controlled oscillator. The body movement interference cancellation module is wirelessly coupled to the physiological signal sensing module to offset a body movement signal of the subject. The body movement interference cancellation module includes: a second antenna, transmitting a second transmission wireless signal to the subject, and receiving a second reflected wireless signal reflected by the subject; and a second pressure Controlling an oscillator, directly connected to the second antenna, outputting the second transmit wireless signal to the second antenna, and receiving the second reflected wireless signal via the second antenna, so that the at least one body moves The interference cancellation module is in the self-injection lock. The first antenna transmits the first transmit wireless signal to the second antenna of the at least one body movement interference cancellation module, and the first transmit wireless signal is controlled by the second voltage via the second antenna Received by the oscillator. The second antenna transmits the second transmit wireless signal to the first antenna of the physiological signal sensing module, and the second transmit wireless signal is used by the first voltage controlled oscillator via the first antenna receive. In this way, a mutual injection lock is achieved between the physiological signal sensing module and the at least one body movement interference canceling module.

According to another exemplary embodiment of the present invention, a non-contact physiological signal sensing method is provided, including: a physiological signal sensing module transmitting a first transmitted wireless signal to a subject, and receiving by the subject Reflecting one of the first reflected wireless signals such that a first voltage controlled oscillator is in a self-injection lock; a body movement interference canceling module is used to offset one of the subject's body movement signals, transmitting a first Transmitting a wireless signal to the subject, and receiving a second reflected wireless signal reflected by the subject, such that a second voltage controlled oscillator is in the self-injection lock; and the physiological signal sensing module receives The second transmit wireless signal, the body movement interference cancellation module receives the first transmit wireless signal, such that a mutual injection lock is achieved between the first voltage controlled oscillator and the second voltage controlled oscillator.

In order to better understand the above and other aspects of the present case, the following examples are given in detail, and in conjunction with the drawings, a detailed description is as follows:

Several embodiments of the present disclosure disclose a non-contact physiological signal sensing system. The principle of operation is that the radio wave can be subjected to the Doppler effect caused by the disturbance of the physiological signals of the subject (such as breathing and heartbeat), so that the frequency change of the radio wave signal corresponds to the physiological signal of the subject.

In several embodiments of the present invention, a self-injection locking (SIL) of an individual voltage controlled oscillator (VCO) is used to cause a voltage controlled oscillator to track a radio wave signal that generates a Doppler effect to detect a subject. Physiological signals. And through the mutual injection locking (MIL) phenomenon between two or more voltage controlled oscillators, which is caused by the body movement (may be random movement of the body or regular movement of the body) during the sensing period. Interference. When sensing, the subject's body movement will produce additional Doppler shift, if it can not offset the body movement information, in principle, will lead to a reduction in the accuracy of the sensing results.

In some embodiments of the present invention, the frequency change of the physiological signal of the subject is demodulated into a voltage signal via a frequency demodulator, and finally the signal is processed by the signal processing unit to obtain physiological signals such as breathing and heartbeat.

In some embodiments of the present invention, the non-contact physiological signal sensing system includes a physiological signal sensing module and one or more body movement interference cancellation modules. The physiological signal sensing module and one or more body movement interference cancellation modules are all operated in a self-injection locked state, and an isotropic physiological signal and a reverse body movement signal are obtained.

Referring to Figures 1A and 1B, a block diagram of a system embodiment of the non-contact physiological signal sensing system 100 and 100' of the present invention is shown. The non-contact physiological signal sensing system 100 includes a physiological signal sensing module 100A and a body movement interference cancellation module 100B. The physiological signal sensing module 100A includes an antenna 10, a voltage controlled oscillator 20, a frequency demodulating unit 30, and a signal processing unit 40. The body movement interference cancellation module 100B includes an antenna 50 and a voltage controlled oscillator 60. The non-contact physiological signal sensing system 100' includes a physiological signal sensing module 100A and a body movement interference canceling module 100B'. The body movement interference cancellation module 100B' of the non-contact physiological signal sensing system 100' further includes a frequency control unit 70.

The antenna 10 is electrically connected to the output port of the voltage controlled oscillator 20, and the output signal of the voltage controlled oscillator 20 is emitted toward the subject (for example, toward the heart portion of the front side of the subject). After the reflected signal is received by the antenna 10, the physiological signal sensing module 100A is operated in a self-injection locked state. Due to Dubu The relationship between the effects of the Le, the frequency at which the transmitted signal from the antenna 10 is transmitted to the subject is different from the frequency of the reflected signal reflected by the subject.

The oscillation frequency of the voltage controlled oscillator 20 of the physiological signal sensing module 100A is determined by the signal processing unit 40. The voltage controlled oscillator 20 outputs and receives signals via the same antenna 10 such that the voltage controlled oscillator 20 is in a self-injection locked state. That is, the output signal of the voltage controlled oscillator 20 is transmitted via the antenna 10, and the signal received by the antenna 10 is input to the voltage controlled oscillator 20 such that the voltage controlled oscillator 20 is in a self-injection locked state. In the present case, the "voltage controlled oscillator 20 is in a self-injection locked state" has the same meaning as "the physiological signal sensing module 100A is in a self-injection locked state".

The output of the voltage controlled oscillator 20 of the physiological signal sensing module 100A is electrically connected to the input port of the frequency demodulating unit 30. The frequency demodulating unit 30 demodulates the frequency variation of the voltage controlled oscillator 20 into a voltage signal. The output of the frequency demodulation unit 30 is electrically coupled to the input port of the signal processing unit 40. The demodulated signal can be processed by signal processing unit 40 (such as, but not limited to, digital filtering and Fourier transform) to obtain the time domain waveform and frequency of the breath and heartbeat.

The output of the signal processing unit 40 is electrically connected to the voltage input 埠 of the voltage controlled oscillator 20 to determine the oscillation frequency of the voltage controlled oscillator 20.

The antenna 50 is electrically connected to the output port of the voltage controlled oscillator 60, and the output signal of the voltage controlled oscillator 60 is transmitted toward the subject (such as the heart portion facing the back of the subject), and the reflected signal is received by the antenna 50. The body movement interference cancellation module 100B/100B' operates in a self-injection locked state. Due to the Doppler effect, the signal transmitted by the antenna 50 to the subject is transmitted. The frequency is different from the frequency of the reflected signal reflected by the subject.

The oscillation frequency of the voltage controlled oscillator 60 of the body movement interference canceling module 100B' is determined, for example, by the frequency control unit 70. The voltage controlled oscillator 60 outputs and receives signals via the same antenna 50 such that the voltage controlled oscillator 60 is in a self-injection locked state. That is, the output signal of the voltage controlled oscillator 60 is transmitted via the antenna 50, and the signal received by the antenna 50 is input to the voltage controlled oscillator 60 such that the voltage controlled oscillator 60 is in a self-injection locked state. In the present specification, the "voltage controlled oscillator 60 is in a self-injection locked state" has the same meaning as the "body movement interference canceling module 100B/100B' is in a self-injection locked state".

The output signal of the voltage controlled oscillator 20 is sent to the antenna 50 via the antenna 10 to be received by the voltage controlled oscillator 60. Similarly, the output signal of the voltage controlled oscillator 60 is sent to the antenna 10 via the antenna 50 to It is received by the voltage controlled oscillator 20 such that the mutual control of the voltage controlled oscillators 20 and 60 is completed. In the present specification, "the mutual injection locking state is achieved between the voltage controlled oscillators 20 and 60" means the same as "the physiological signal sensing module 100A and the body movement interference canceling module 100B/100B' are mutually injected. Locked status."

In the body movement interference cancellation module 100B', the output of the frequency control unit 70 is electrically connected to the input port of the voltage controlled oscillator 60 to determine the oscillation frequency of the voltage controlled oscillator 60. In an embodiment, the oscillation frequencies of the voltage controlled oscillators 20 and 60 will be the same.

In an embodiment, the transmit signals of the physiological signal sensing module 100A and the body motion interference cancellation module 100B/100B' will also be received by each other to create a mutual injection locking phenomenon. During the sensing process, breathing and heartbeat are respectively The lungs and the heart are periodically expanded and contracted, so that the physiological signal is an isotropic signal for the physiological signal sensing module 100A and the body movement interference canceling module 100B/100B'. The body movement is in a single direction, so for the physiological signal sensing module 100A and the body movement interference cancellation module 100B/100B', the body movement signal is a reverse signal.

For example, when the heart expands, the physiological signal sensing module 100A and the body movement interference cancellation module 100B/100B' detect that the human heart position is close to the sensing module 100A and 100B/100B'. This is the meaning of "the physiological signal is an isotropic signal." For example, if the body movement of the subject is toward the physiological signal sensing module 100A, the physiological signal sensing module 100A detects that the subject's body moves toward it, but the body moves. The interference cancellation module 100B/100B' detects that the subject's body moves away from it. This is the meaning of "the body movement signal is a reverse signal". Therefore, in the embodiment, the locking phenomenon is injected between the two sensing modules 100A and 100B/100B' to offset the interference generated by the body movement. Since the body movement signal is a reverse signal to the two sensing modules 100A and 100B/100B', it can be offset. That is, if the body movement signal is the same direction signal for the two sensing modules 100A and 100B/100B' because of the placement positions of the two sensing modules 100A and 100B/100B', the body movement signal May not be offset.

In addition, during the physiological sensing, if the subject's body moves, physiological information such as breathing and heartbeat and body movement signals can be sensed in the chest position of the subject; but only the observable person's abdominal position can be observed. Move the signal to the body.

Figure 2 shows a non-contact physiological signal sensing system embodiment 100' Schematic diagram. In the present embodiment, the frequency demodulating unit 30 includes, for example, a mixer 31, a delay unit 32, and a filter 33. The signal processing unit 40 includes, for example, an analog/digital converter (ADC) 41, a digital/analog converter (DAC) 42, and a digital signal processor (DSP) 43. It is to be understood that in other possible embodiments of the present invention, the frequency demodulation unit 30 and the signal processing unit 40 may have other architectures.

The antenna 10 is electrically connected to the differential signal output 埠O1 of the voltage controlled oscillator 20 for transmitting the signal Sout1 toward the heart portion of the front side of the subject. The voltage controlled oscillator 20 has a voltage input 埠V1 and a differential signal output 埠O1. In the present embodiment, the voltage controlled oscillator 20 outputs two differential output signals Sout1 and Svco1, one of which is input to the antenna 10, and the other differential output signal Svco1 is input to the frequency demodulating unit 30.

In the present embodiment, there are many ways in which the voltage controlled oscillator 20 generates the differential output signals Sout1 and Svco1. For example, in one approach, the voltage controlled oscillator 20 produces a single differential output signal that is decomposed into differential output signals Sout1 and Svco1 by a power divider; in this case, the differential output signal Sout1 and Svco1 are identical to each other. In another possible approach, the voltage controlled oscillator 20 directly outputs two differential output signals Sout1 and Svco1, and the phases of the two differential output signals Sout1 and Svco1 do not have to be the same.

The antenna 50 is electrically connected to the signal output 埠O2 of the voltage controlled oscillator 60 for transmitting the signal Sout2 toward the heart portion of the back of the subject. The voltage controlled oscillator 60 has a voltage input 埠V2 and a differential signal output 埠O2.

In the embodiment of the present invention, the signal Sinj1 is reflected by the subject (ratio For example, the reflected signal is reflected by the heart position of the front side of the human body of the subject, and the signal Sout2 emitted by the body movement interference canceling module 100B' to the physiological signal sensing module 100A. The signal Sinj1 is received by the antenna 10 of the physiological signal sensing module 100A, and is electrically connected to the differential signal output 埠O1 of the voltage controlled oscillator 20. The signal Sinj2 is reflected by the subject (for example, the reflected signal is reflected by the heart position of the back side of the subject), and the signal Sout1 of the physiological signal sensing module 100A is transmitted to the body movement interference canceling module 100B'. composition. The signal Sinj2 is received by the antenna 50 of the body movement interference cancellation module 100B' and is electrically coupled to the differential signal output 埠O2 of the voltage controlled oscillator 60. The physiological signal sensing module 100A and the body movement interference canceling module 100B' will simultaneously generate a self-injection locking phenomenon and a mutual injection locking phenomenon. In this embodiment, physiological signals such as breathing and heartbeat are an isotropic signal to the physiological signal sensing module 100A and the body movement interference canceling module 100B'; the body movement signal is related to the physiological signal sensing module 100A and the body movement. The interference cancellation module /100B' is a reverse signal.

By the self-injection locking phenomenon, the physiological signal sensing module 100A and the body movement interference cancellation module 100B' can obtain the same physiological information, and the body movement information for the reverse signal can be injected and locked by mutual phenomenon. The RF front-end circuit is offset.

In the embodiment of the present invention, the frequency demodulating unit 30 of the physiological signal sensing module 100A is electrically connected to the other end of the differential signal output 埠O1 of the voltage controlled oscillator 20 for observing the output signal of the voltage controlled oscillator 20. The frequency change of Sout1.

The mixer 31 is electrically connected to the other end of the differential signal output 埠O1 of the voltage controlled oscillator 20 to mix the differential output signal Svco1 and the delay list. The output signal of element 32. The two ends of the delay unit 32 are electrically connected to the other end of the differential signal output 埠O1 of the mixer 31 and the voltage controlled oscillator 20, and the differential output signal Svco1 is delayed and input to the mixer 31. A filter 33, such as a low pass filter 33, is electrically coupled to the output of the mixer 31 to filter the output of the mixer 31 (e.g., to filter out high frequency noise).

The signal processing unit 40 is electrically connected to the output of the low pass filter 33 and the voltage input 埠V1 of the voltage controlled oscillator 20. The signal processing unit 40 outputs an analog control voltage Vt1, wherein the analog control voltage Vt1 adjusts the output frequency of the voltage controlled oscillator 20. The frequency control unit 70 of the body movement interference canceling module 100B' is electrically connected to the voltage input 埠V2 of the voltage controlled oscillator 60. The frequency control unit 70 outputs an analog control voltage Vt2, and the analog control voltage Vt2 adjusts the output frequency of the voltage controlled oscillator 60. The physiological signal sensing module 100A and the body movement interference canceling module 100B' have the same operating frequency to operate in a mutual injection locking state.

The analog/digital converter 41 is electrically coupled to the output of the frequency demodulation unit 30 for analog-to-digital conversion of the output signal of the filter 33. The digital/analog converter 42 is electrically connected to the voltage input 埠V1 of the voltage controlled oscillator 20. The digital signal processor 43 is electrically connected to the analog/digital converter 41 and the digital/analog converter 42. The digital signal processor 43 processes the digital output signal of the analog/digital converter 41 to produce a processing result (such as a physiological signal of the subject). In addition, the digital signal processor 43 generates a digital control signal to the digital/analog converter 42. The digital/analog converter 42 performs digital/analog conversion of the digital control signal generated by the digital signal processor 43 to generate an analog control voltage Vt1 to control the voltage controlled vibration. The oscillation frequency of the squaring device 20.

The frequency demodulating unit 30 receives the differential signal output signal Svco1 of the voltage controlled oscillator 20 to generate a narrow frequency analog signal Sdemod. The analog/digital converter 41 samples the narrowband analog signal Sdemod, and the digital signal processor 43 determines the sampling result of the analog/digital converter 41 to obtain the time domain waveform and frequency of the breath and heartbeat.

In addition to the frequency control unit 70 and the analog control voltage Vt2 in FIG. 2, the remaining architecture in FIG. 2 can also be illustrated as an implementation of FIG.

Figure 3 shows a schematic diagram of the implementation of a Doppler radar sensor using a self-injection locking technique in accordance with an embodiment of the present invention. The position of the antenna 10 and the subject is different by d0, and the voltage controlled oscillator 20 sends a signal Sout1 to the chest position of the human body, and after reaching the delay of τ p , the chest surface can be reached. τ p=d0/c, c is the speed of light. Since the heartbeat and breathing cause the chest cavity to undulate, the Doppler effect is generated, and the RF signal Sout1 is phase-modulated. The signal reflected by the subject is received by the antenna 10 after τ p and injected into the voltage controlled oscillator 20 to cause the voltage controlled oscillator 20 to enter a self-injection locked state. The other output signal Svco1 of the voltage controlled oscillator 20 is sent to the frequency demodulator 30 for demodulation and outputs a baseband signal for the signal processing unit 40 at the rear end to determine the physiological information.

Figure 4 is a diagram showing the use of mutual injection locking to offset body movement interference at the radio frequency end in accordance with an embodiment of the present invention. In the present embodiment, the method of offsetting body movement interference is to use at least two sets of sensing modules 100A and 100B/100B'. As mentioned above, the movement of the human body is unidirectional, while the expansion and contraction of the lungs or the heart is multi-directional or omnidirectional. Sensing mode Groups 100A and 100B/100B' use self-injection locking techniques to detect physiological signals and body movements, and use mutual injection locking to achieve synchronization effects to counteract body movement information while leaving physiologically sensed information.

In Fig. 4, 4A and 4B respectively represent body movement signals sensed by physiological signal sensing module 100A and body movement interference cancellation module 100B/100B'; 4C and 4D respectively represent physiological signal sensing modes The group 100A and the body movement interfere with the physiological signals sensed by the module 100B/100B'. 4E represents the physiological signal obtained after offsetting the body movement signal. That is, in the embodiment of the present invention, the physiological signal can be detected even when the subject's body moves.

Please refer to FIGS. 5A and 5B, which show experimental sensing results according to an embodiment of the present invention to show the offset effect on regular movement. For example, a metal plate is placed in the sensing device to simulate the body movement of the subject. The metal plates are, for example, periodically moved, and their moving distances are 1, 2, 3, and 4 cm, respectively. In the 5A and 5B, the solid line segment is the sensing result obtained by using the physiological signal sensing module 100A, and the dotted line segment is the physiological signal sensing module 100A and the body movement interference canceling module 100B/100B. 'The resulting sensory results. Comparing the square roots of the two line segments, it can be seen that the offset effect is over 90%. Therefore, it can be proved that the embodiment of the present invention does have the effect of offsetting the body movement.

Please refer to FIGS. 6A-6D, which show another experimental sensing result of the embodiment of the present case to show the offset effect on random (irregular) movement. Figures 6A and 6B (before offset) show that when the subject is running on a treadmill, only the physiological signal sensing module 100A is used to sense the results. 6A and 6B are time domain waveforms of the sensing results before offsetting, respectively With spectrum waveforms. Due to the random movement of the subject's body, the waveform exhibits dramatic and irregular fluctuations. After the Fourier transform, as shown in the spectrogram of Figure 6B, only the respiratory main frequency is about 0.5 Hz, but the heartbeat frequency and the random movement signal of the body cannot be distinguished.

The 6C and 6D images (after offset) show the sensing results obtained by the physiological signal sensing module 100A and the body movement interference canceling module 100B/100B' when the subject is running on the treadmill. The 6C and 6D graphs are the time domain waveform and the spectrum waveform of the sensing result after the offset, respectively. It can be seen that the waveforms of the 6C and 6D are relatively regular and contain physiological information such as breathing and heartbeat. As can be seen from the spectrogram of Figure 6D, the identifiable respiratory frequency and heartbeat frequency are about 0.5 Hz and 2.16 Hz, respectively, that is, 30 breaths/minute and 130 beats/minute, which is related to other medical instruments. Consistent.

In the embodiment, the signal transmitting end and the signal receiving end are the same end point (the differential signal output end of the VCO), and no isolation circuit is needed between the end point and the antenna. In addition, since the present embodiment uses mutual injection locking, the two sensing modules 100A and 100B/100B' are coupled with each other by using radio frequency signals, so that the two sensing modules 100A and 100B/100B' have synchronous operation. relationship.

The non-contact physiological signal sensing system of the embodiment of the present invention is based on self-injection locking and mutual injection locking. Compared with the traditional physiological signal sensing system with the Doppler radar architecture and the basic frequency signal processing technology, the self-injection locking technology can improve the sensing sensitivity in principle, and the mutual injection locking technology is improved. The method of offsetting the body movement signal of the subject in the RF front-end circuit may have the ability to reduce components and reduce System complexity and reduced power loss.

In the embodiment of the present invention, the two sensing modules operate at the same frequency and the same polarization direction, and the two sensing modules are synchronized with each other by using the mutual injection locking mechanism. Therefore, in principle, the body can be randomly moved to interfere with the front end of the RF circuit. pin. Because the information obtained by the two sensing modules is consistent and uses a set of baseband signal outputs, the system architecture can be simplified.

In principle, the embodiments of the present invention can provide reliable and correct physiological sensing results since the subject's body movement disturbances during sensing are offset. The scope of application of the embodiments of the present invention includes, for example, but not limited to, long-term respiratory and heartbeat monitoring of patients with cardiopulmonary diseases, avoiding sudden death of the baby, and physiological signal monitoring of exercise equipment. In this way, it is not limited to the measurement location, and the medical resources can be effectively utilized. Moreover, the embodiment of the present invention can also be applied to industries such as entertainment and leisure, for example, for somatosensory entertainment that performs corresponding actions with body movement, and can also be applied to other appropriate fields.

Reference is now made to Figures 7A through 7C, which show system block diagrams of a non-contact physiological signal sensing system in accordance with other possible embodiments of the present invention. Fig. 7A shows that the physiological signal sensing module 100A and the body movement interference canceling module 100B/100B' are placed on the same side of the subject, but the body movement interference can still be offset. In Figs. 1A and 1B, the physiological signal sensing module 100A and the body movement interference canceling module 100B/100B' are placed on the front and rear sides of the subject. In Fig. 7A, the physiological signal sensing module 100A faces the chest position of the subject, and the body movement interference canceling module 100B/100B' faces the abdominal cavity position of the subject. By adjusting the placement position and operating frequency of the two sensing modules 100A and 100B/100B', the two sensing modules 100A and 100B/100B' can detect the opposite body movement signal, and the sensing module The 100A can sense the physiological signal information of the subject. By the mutual injection locking mechanism, the sensing modules 100A and 100B/100B' are placed on the same side of the subject to offset the body movement interference.

In addition, other possible embodiments of the present invention can also offset multi-dimensional body movement interference, such as FIG. 7B and FIG. 7C. Both the 7B and 7C circuit architectures can offset two-dimensional body movement interference. The circuit architectures of FIG. 7B and FIG. 7C use multiple sets of sensing modules of the same operating frequency, but only need to process a set of fundamental frequency signals, so in principle only one physiological signal sensing module 100A is needed, which can save more effectively. System cost and circuit complexity.

Moreover, in other possible embodiments of the present invention, the frequency demodulation unit may have other practices in addition to the embodiment of FIG. Figures 8A through 8D show several other possible approaches of the frequency demodulation unit in accordance with other embodiments of the present invention.

In FIG. 8A, the frequency demodulating unit 30A is a quadrature demodulator including a mixer 811 and a phase shifting unit 812. The phase shifting unit 812 adjusts the phase of the input frequency modulated signal such that its input signal and the output signal differ by a phase difference of 90 degrees. The mixer 811 multiplies the input frequency modulation signal by the output signal of the phase shifting unit 812 to obtain a demodulated signal.

In FIG. 8B, the frequency demodulating unit 30B is a PLL demodulator, which includes: a phase detector (Phase Detector) 821, a loop filter 822, a voltage controlled oscillator 823, and a frequency divider (Frequency). Divider) 824. The architecture of Figure 8B is similar to the Phase Locked Loop, hence the name PLL demodulator. The phase detector 821 produces the input frequency modulated signal and the voltage controlled oscillator 823/frequency divider 824. The raw signal is phase-compared, and the loop filter 822 loop filters the phase comparison result of the phase detector 821 to generate a frequency control voltage. This frequency control voltage locks the frequency of the voltage controlled oscillator 823, synchronizing the input frequency modulated signal with the output signal of the voltage controlled oscillator. This frequency adjustment voltage is the frequency modulation information of the frequency modulation signal.

In Fig. 8C, the frequency demodulating unit 30C is a synchronous demodulator-IQ demodulator. The frequency demodulation unit 30C includes: mixers 831 and 832, a phase shift unit 833, low pass filters 834 and 835, a phase lock loop 836, and a digital signal processor (DSP) 837. The input frequency modulation signals are input to the mixers 831 and 832, respectively. The respective switch stage signals of the two mixers 831 and 832 are provided by the phase lock loop 836, but the phases of the two switch stage signals differ by 90 degrees. After the output signals of the two mixers 831 and 832 pass through the low pass filters 834 and 835, respectively, to filter out the intermodulation signals, the frequency modulation information can be obtained by the DSP 837.

In Fig. 8D, the frequency demodulating unit 30D includes a phase demodulator 841 and a differentiator 842. The input frequency modulated signal is input to the phase demodulator 841 to obtain its phase change. The differentiator 842 differentiates to obtain frequency modulation information.

Figure 9 is a flow chart showing a non-contact physiological signal sensing method according to other embodiments of the present invention. The non-contact physiological signal sensing method includes: in step S910, the physiological signal sensing module transmits the first transmitting wireless signal to the subject, and receives the first reflected wireless signal reflected by the subject, so that the first voltage control The oscillator is in self-injection locking; in step S920, the body movement interference cancellation module is configured to offset one of the subject's body movement signals, transmit a second transmitting wireless signal to the subject, and receive the measured The second reflected wireless signal reflected by the second voltage controlled oscillator is in the self-injection locking; and in step S930, the physiological signal sensing module receives the second transmitting wireless signal, and the body movement interference canceling module receives the first The wireless signal is transmitted such that a mutual injection lock is achieved between the first voltage controlled oscillator and the second voltage controlled oscillator. The details of steps S910 to S930 are as described above, and therefore are omitted here.

Moreover, in the embodiment of the present invention, the physiological signal sensing module and/or the body movement interference canceling module can be implemented by a hardware circuit. However, in other embodiments, a portion of the physiological signal sensing module and/or the body movement interference cancellation module may be implemented by a soft body and/or a firmware.

In summary, although the present invention has been disclosed above by way of example, it is not intended to limit the present invention. Those who have ordinary knowledge in the technical field of the present invention can make various changes and refinements without departing from the spirit and scope of the present case. Therefore, the scope of protection of this case is subject to the definition of the scope of the patent application attached.

100, 100'‧‧‧ Non-contact physiological signal sensing system

100A‧‧‧ Physiological Signal Sensing Module

100B/100B’‧‧‧ Body Movement Interference Offset Module

10, 50‧‧‧ antenna

20, 60‧‧‧voltage controlled oscillator

30‧‧‧frequency demodulation unit

40‧‧‧Signal Processing Unit

70‧‧‧frequency control unit

31‧‧‧Mixer

32‧‧‧Delay unit

33‧‧‧ filter

41‧‧‧ Analog/Digital Converter

42‧‧‧Digital/Analog Converter

43‧‧‧Digital Signal Processor

4A, 4B‧‧‧ body movement signals

4C, 4D, 4E‧‧‧ physiological signals

30A, 30B, 30C, 30D‧‧‧ frequency demodulation unit

811‧‧‧Mixer

812‧‧‧ Phase shifting unit

821‧‧‧ phase detector

822‧‧‧ Loop Filter

823‧‧‧Variable Control Oscillator

824‧‧‧Delephone

831, 832‧‧‧ Mixer

833‧‧‧ phase shifting unit

834, 835‧‧‧ low pass filter

836‧‧‧ phase locked loop

837‧‧‧Digital Signal Processor

841‧‧‧ phase demodulator

842‧‧‧ Differentiator

S910~S930‧‧‧Steps

1A and 1B are block diagrams showing a system embodiment of the non-contact physiological signal sensing system of the present invention.

Figure 2 shows a schematic of an embodiment of a non-contact physiological signal sensing system.

Figure 3 shows a schematic diagram of the implementation of a Doppler radar sensor using a self-injection locking technique in accordance with an embodiment of the present invention.

Figure 4 is a diagram showing the use of mutual injection locking to offset body movement interference at the radio frequency end in accordance with an embodiment of the present invention.

5A and 5B show experimental sensing according to an embodiment of the present invention As a result, the offset effect on the regular movement is shown.

6A to 6D show another experimental sensing result of the present embodiment to show the offsetting effect on random (irregular) movement.

7A through 7C are system block diagrams showing a non-contact physiological signal sensing system in accordance with other possible embodiments of the present invention.

Figures 8A through 8D show several other possible approaches of the frequency demodulation unit in accordance with other embodiments of the present invention.

Figure 9 is a flow chart showing a non-contact physiological signal sensing method according to other embodiments of the present invention.

100‧‧‧ Non-contact physiological signal sensing system

100A‧‧‧ Physiological Signal Sensing Module

100B‧‧‧ Body Movement Interference Offset Module

10, 50‧‧‧ antenna

20, 60‧‧‧voltage controlled oscillator

30‧‧‧frequency demodulation unit

40‧‧‧Signal Processing Unit

Claims (14)

A non-contact physiological signal sensing system includes: a physiological signal sensing module, sensing a physiological signal of a subject, comprising: a first antenna, transmitting a first transmitted wireless signal to the measured And receiving a first reflected wireless signal reflected by the subject; a first voltage controlled oscillator directly connected to the first antenna, and outputting the first transmit wireless signal to the first antenna, Receiving, by the first antenna, the first reflected wireless signal, so that the physiological signal sensing module is in a self-injection lock; a frequency demodulating unit coupled to the first voltage controlled oscillator, demodulating the a frequency change of one of the first voltage controlled oscillators; and a signal processing unit coupled to the frequency demodulation unit and the first voltage controlled oscillator, and analyzing the received voltage according to the frequency change of the first voltage controlled oscillator Detecting the physiological signal and determining a first oscillation frequency of the first voltage controlled oscillator; and at least one body movement interference cancellation module wirelessly coupled to the physiological signal sensing module to offset the measured One of the body movement signals Each of the body movement interference cancellation module includes: a second antenna, transmitting a second transmitted wireless signal to the subject, and receiving a second reflected wireless signal reflected by the subject; a second a voltage controlled oscillator directly connected to the second antenna, outputting the second transmit wireless signal to the second antenna, and receiving the second reflected wireless signal via the second antenna, so that the at least one body The mobile interference cancellation module is in the self-injection lock; a frequency control unit coupled to the second voltage controlled oscillator to determine a second oscillation frequency of the second voltage controlled oscillator, wherein the first oscillation frequency of the first voltage controlled oscillator is the same as the second voltage control The second oscillating frequency of the oscillator; wherein the first antenna transmits the first transmit wireless signal to the second antenna of the at least one body movement interference cancellation module, and the first transmit wireless signal passes the The second antenna is received by the second voltage controlled oscillator; the second antenna transmits the second transmit wireless signal to the first antenna of the physiological signal sensing module, and the second transmit wireless signal The first voltage controlled oscillator is received by the first antenna; and the mutual injection locking is achieved between the physiological signal sensing module and the at least one body movement interference canceling module. The non-contact physiological signal sensing system of claim 1, wherein the first transmitted wireless signal and the first reflected wireless signal have different frequencies; and the second transmitted wireless signal and the second reflected Wireless signals have different frequencies. The non-contact physiological signal sensing system of claim 1, wherein the physiological signal of the subject is the same as the physiological signal sensing module and the at least one body movement interference cancellation module. Directional signal. The non-contact physiological signal sensing system described in claim 3, wherein The body movement signal of the subject is a reverse signal to the physiological signal sensing module and the at least one body movement interference cancellation module. The non-contact physiological signal sensing system of claim 4, wherein the physiological signal sensing module and the at least one body movement interference cancellation module are located in the subject during sensing Opposite side. The non-contact physiological signal sensing system of claim 4, wherein the physiological signal sensing module and the at least one body movement interference cancellation module are located in the subject during sensing The same side. The non-contact physiological signal sensing system of claim 1, further comprising a plurality of body movement interference cancellation modules, transmitting a plurality of the second transmitting wireless signals from the plurality of directions to the subject, The multi-dimensional body movement signal of the subject is offset. A non-contact physiological signal sensing method includes: a physiological signal sensing module transmitting a first transmitted wireless signal to a subject, and receiving a first reflected wireless signal reflected by the subject, such that a first voltage controlled oscillator is in a self-injection lock; a body movement interference cancellation module offsets one of the subject's body movement signals, transmits a second transmitted wireless signal to the subject, and receives the a second reflected wireless signal reflected by the subject, such that a second voltage controlled oscillator is in the self-injection lock, and the body movement interference cancellation module further includes a frequency control unit to determine the second a second oscillation frequency of one of the voltage controlled oscillators, wherein the first oscillation frequency of the first voltage controlled oscillator is the same as the second oscillation frequency of the second voltage controlled oscillator; The physiological signal sensing module receives the second transmitting wireless signal, and the body movement interference cancellation module receives the first transmitting wireless signal, so that the first voltage controlled oscillator and the second voltage controlled oscillator are A mutual injection lock. The non-contact physiological signal sensing method of claim 8, further comprising: transmitting the first transmitting wireless signal to the subject via a first antenna; the first voltage controlled oscillator outputs the First transmitting a wireless signal to the first antenna, the first voltage controlled oscillator receiving the first reflected wireless signal via the first antenna, such that the first voltage controlled oscillator is in the self injection lock; Adjusting a frequency change of the first voltage controlled oscillator; and analyzing a physiological signal of the one of the subjects according to the frequency change of the first voltage controlled oscillator, and determining one of the first voltage controlled oscillators An oscillating frequency; transmitting the second transmit wireless signal to the subject via a second antenna; and the second voltage controlled oscillator outputting the second transmit wireless signal to the second antenna, the second voltage control The oscillator receives the second reflected wireless signal via the second antenna such that the second voltage controlled oscillator is in the self-injection lock; wherein the first antenna transmits the first transmit wireless signal to the second Antenna, and the first transmitting wireless The signal is subjected to the second pressure via the second antenna Received by the controlled oscillator; the second antenna transmits the second transmit wireless signal to the first antenna, and the second transmit wireless signal is received by the first voltage controlled oscillator via the first antenna; The first transmitted wireless signal has a different frequency than the first reflected wireless signal; and the second transmitted wireless signal and the second reflected wireless signal have different frequencies. The non-contact physiological signal sensing method according to claim 8, wherein the physiological signal of one of the subjects is an isotropic signal. The non-contact physiological signal sensing method according to claim 10, wherein the body movement signal of the subject is a reverse signal. The non-contact physiological signal sensing method of claim 11, wherein the first transmitting wireless signal and the second transmitting wireless signal are transmitted to the opposite side of the subject during sensing. The non-contact physiological signal sensing method of claim 11, wherein the first transmitting wireless signal and the second transmitting wireless signal are transmitted to the same side of the subject during sensing. The non-contact physiological signal sensing method of claim 8, further comprising: transmitting a plurality of the second transmitting wireless signals from the plurality of directions to the receiving The tester offsets the multi-dimensional body movement signal of the subject.