TWI476379B - Non-contact motion detection apparatus - Google Patents

Description

Non-contact disturbance sensing device

The present disclosure relates to a non-contact disturbance sensing device.

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, there are a variety of physiological signal measuring devices for monitoring the physiological signals of the subject, so that the subject can detect their health.

There are currently contact physiological signal sensing devices and non-contact physiological signal sensing devices. The contact type physiological signal sensing device performs measurement by contacting the human body, and the circuit composition thereof is simple, but if the human skin is contacted for a long time, the subject may feel uncomfortable. Compared with the contact physiological signal sensing device, the non-contact physiological signal sensing device can reduce the discomfort of the subject during the sensing process.

Therefore, this case proposes a non-contact disturbance sensing device, which can detect the chest undulation of the subject without contact, and then analyze the physiological parameters (such as breathing, heartbeat frequency, etc.) of the person to be tested, or other external disturbance information. . This case also applies to motion detectors, or to detect mechanical vibration frequencies.

The present disclosure provides a non-contact disturbance sensing device that locks the output frequency of a voltage controlled oscillator (VCO) with a phase locked loop. When the external disturbance, such as the chest of the test subject, causes the output frequency of the VCO to change, the phase-locked loop adjusts the control voltage of the VCO by the feedback mechanism to stabilize the VCO output frequency, so that the control voltage of the phase-locked loop can reflect the outside world. Disturbing information. The phase-locked loop has the functions of (1) fixed output frequency and (2) frequency demodulation.

An embodiment of the present disclosure provides a non-contact disturbance sensing device, including: at least one receiving antenna for receiving a first radio frequency signal; and at least one transmitting antenna for transmitting a second radio frequency signal to a test An object, the object to be tested reflects the second radio frequency signal to become the first radio frequency signal; a voltage controlled oscillator is coupled to the at least one receiving antenna and the at least one transmitting antenna, and the voltage controlled oscillator outputs an oscillation Transmitting the signal to the at least one transmitting antenna, and the first radio frequency signal received by the at least one receiving antenna is injected into the voltage controlled oscillator; and a phase locked loop according to the oscillating signal generated by the voltage controlled oscillator A reference voltage is generated to generate a control voltage to the voltage controlled oscillator. The control voltage locks the oscillation signal frequency of the voltage controlled oscillator to the reference frequency, and the control voltage reflects one of the object to be tested.

Another embodiment of the present disclosure provides a non-contact disturbance sensing device, including: at least one antenna for receiving a first radio frequency signal and transmitting a second radio frequency signal, wherein the object to be tested reflects the second radio frequency The signal is the first radio frequency signal; a voltage controlled oscillator is coupled to the at least one antenna, the voltage controlled oscillator outputs an oscillating signal to the at least one antenna, and the first wireless is received by the at least one antenna Transmitting a radio frequency signal to the voltage controlled oscillator; and a phase locked loop, generating a control voltage to the voltage controlled oscillator according to the oscillating signal generated by the voltage controlled oscillator and a reference frequency, the control voltage making the voltage The frequency of the oscillating signal of the controlled oscillator is locked to the reference frequency, and the control voltage reflects one of the disturbance information of the object to be tested.

In order to better understand the above and other aspects of the present invention, the following specific embodiments, together with the drawings, are described in detail below:

In addition to physiological signal sensing, the present invention is also applicable to motion detectors, or detecting mechanical vibration frequencies. The following is an example of physiological signal sensing, but is not limited to this application.

In several embodiments of the present disclosure, when the VCO is subjected to external interference, the output frequency of the VCO may vary. Therefore, the physiological parameters or the motion parameters of the object to be tested can be known from the change of the output frequency of the VCO.

Because the human chest undulation causes the Doppler effect, which will cause the VCO output frequency to drift, in several embodiments of the present disclosure, the PLL is used to lock the output frequency of the VCO so that it does not drift. In addition, the control voltage of the PLL will reflect the change information of the output frequency of the VCO, and the voltage controlled by the PLL can reflect the physiological signal of the human body.

The non-contact disturbance sensing device of the embodiment of the present disclosure can non-contactly detect physiological parameters such as breathing and heart rate of a person.

The disclosed embodiment uses a Voltage Controlled Oscillator (VCO) as a detecting component, and the chest undulation of the subject is reflected in the VCO output frequency.

In the disclosed embodiment, the phase-locked loop suppresses the change of the VCO output frequency and simultaneously demodulates the VCO output frequency to obtain physiological parameters such as the breathing and heartbeat frequency of the subject.

1 is a block diagram showing a non-contact disturbance sensing device of one embodiment of the present disclosure. Referring to FIG. 1 , the non-contact disturbance sensing device 100 includes antennas 110 , 120 , a voltage controlled oscillator 130 , a processing unit 140 , and a phase locked loop (PLL) 150 .

Antenna 110 (e.g., a receiving antenna) receives a first wireless signal (e.g., a radio frequency modulation signal) and accordingly generates a first electrical signal.

The antenna 120 (eg, a transmitting antenna) is coupled to the output of the voltage controlled oscillator 130, and generates a second wireless signal to the object to be tested 180. The object to be tested 180 reflects the first wireless signal to the antenna 110.

In the present embodiment, the object to be tested 180 is, for example, a human body, and the parameters of the object to be tested 180 are, for example, physiological parameters or motion signals (such as limb movements) such as a heartbeat or a pulse or a breath. Due to the Doppler effect, the frequency of the first wireless signal is different from the frequency of the second wireless signal.

The antenna 110 is coupled to the injection end of the voltage controlled oscillator 130, that is, the first electrical signal received by the antenna 110 is injected into the injection end of the voltage controlled oscillator 130. Under the interference of the first electrical signal, the oscillation frequency of the voltage controlled oscillator 130 is affected. The oscillating signal of the VCO 130 varies as the first electrical signal changes. In this embodiment, the voltage controlled oscillator 130 initiates a self-injection locking action under the interference of the first electrical signal to affect the frequency of the oscillating signal.

The processing unit 140 is coupled to the voltage controlled oscillator 130 and the PLL 150 to evaluate the parameters of the object to be tested 180 according to the control voltage Vc of the PLL 150.

The phase locked loop 150 locks the VCO 130 based on the reference frequency Ref such that the output frequency of the VCO 130 is locked to suppress the frequency drift phenomenon. In this way, in principle, the occupied bandwidth can be reduced.

Hereinafter, the operation of the wireless sensing device 100 will be explained. The antenna 120 transmits a second wireless signal to the object to be tested 180 (such as a human body), and the object to be tested 180 accordingly reflects the first wireless signal to the antenna 110. In this embodiment, due to the breathing of the human body and the fluctuations of the heartbeat or the pulse and the movement of the limbs, the second wireless signal and the relative motion of the breathing and the heartbeat fluctuation or the pulse and the limb movement produce a Doppler effect. Therefore, the frequency of the first wireless signal reflected from the human body is different from the frequency of the second wireless signal emitted by the antenna 120.

The antenna 110 receives the first wireless signal and generates a first electrical signal to the voltage controlled oscillator 130, and the voltage controlled oscillator 130 generates an oscillating signal of the same frequency to the PLL 150 according to the first electrical signal. The PLL 150 generates a control voltage Vc according to a frequency difference and/or a phase difference between the oscillation signal and the reference frequency Ref. The control voltage Vc adjusts the output oscillation frequency of the VCO 130 to coincide with the reference frequency Ref. Observing the control voltage Vc output by the PLL 150 (this control voltage Vc controls and locks the output oscillation frequency of the VCO 130), information such as the heartbeat, respiration, pulse, or other disturbance of the human body can be known.

That is, the oscillating signal of the VCO 130 reflects information such as heartbeat, respiration, pulse, or other disturbances of the human body (ie, parameters of the object to be tested 180). After the oscillating signal is demodulated by the PLL 150, the control voltage Vc is processed, and the processing unit 140 processes the control voltage Vc to obtain information about the heartbeat, breathing, pulse, or motion of the human body, so as to evaluate the body of the subject according to the above information. situation.

In this way, the non-contact disturbance sensing device 100 of the present embodiment does not need to pass the reflected signal and the other path of the output of the power splitter via the mixer and subsequent processing as in the conventional physiological information sensor. It can avoid measuring the zero point and reduce the use of the circuit, reduce the complexity of the system and power consumption.

Further, in the present embodiment, the output of the VCO 130 is referred to as a signal transmitting end, and the output oscillating signal thereof becomes a wireless carrier via the antenna 120. When the wireless carrier signal is reflected by the object to be tested 180, the reflected wave (the reflected wave is emitted by the object to be tested 180) affected by the Doppler effect is received by the antenna 110 and input to the VCO 130, and the VCO 130 receives the injection. Signal impact.

If no PLL 150 or PLL 150 fails, the output oscillation frequency of the VCO 130 is adjusted to match the injected signal. For example, if a fixed voltage is applied to the voltage control terminal of the VCO 130, the output frequency of the VCO 130 drifts with an external disturbance near a certain frequency due to external interference.

Therefore, in the embodiment, the phase locked loop 150 locks the output oscillation signal of the VCO 130. When the external disturbance affects the VCO 130, the phase locked loop 150 adjusts the control voltage Vc input to the VCO 130 with a negative feedback mechanism to stabilize the output oscillation frequency of the VCO 130. The control voltage Vc generated by the phase locked loop 150 can be regarded as reflecting the influence information of the external disturbance. That is, in the present embodiment, the phase locked loop 150 has the dual functions of (1) the output oscillation frequency of the fixed VCO 130 and (2) frequency demodulation.

Moreover, in this embodiment, the processing unit 140 may include, for example but not limited to, an analog digital converter and a digital signal processor. An analog digital converter is used to analogically convert the control voltage output by the phase locked loop 150 to generate a digital signal. The digital signal processor is coupled to the analog digital conversion unit for processing the digital signal generated by the analog digital converter to generate a processing result, which represents a parameter of the object to be tested 180.

Reference is now made to Figs. 2A and 2B, which show functional block diagrams of two possible implementations of PLL 150 in accordance with the present embodiment.

As shown in FIG. 2A, the PLL 150 includes a phase frequency detector (PFD) 210, a charge pump 220, and a low-pass filter (LPF) 230.

The output signal of the VCO 130 and the local reference frequency Ref enter the phase frequency detector (PFD) 210. The output voltage signal of the PFD 210 reflects the phase difference or frequency difference between the output signal of the VCO 130 and the local reference frequency Ref. The output voltage signal of the PFD 210 is input to the charge pump 220 to be converted into a current output. This current output is filtered by the low pass filter 230 to remove the high frequency signal to obtain the control voltage Vc. The control voltage Vc is input to the control terminal of the VCO 130 for controlling the oscillation of the VCO 130. The loop of PLL 150 is a negative feedback characteristic, and the control voltage Vc causes the output frequency of the VCO to track the frequency of the reference frequency Ref.

Therefore, when a reflected wave having a Doppler effect is injected into the VCO 130 such that the VCO 130 has a tendency to frequency drift, the VCO 130 is locked by the phase locked loop 150 and fixed to the reference frequency Ref. Therefore, the control voltage Vc of the control terminal of the VCO 130 reflects this frequency drift tendency and produces a voltage change that is reversed from this frequency drift. That is, in the present embodiment, the external disturbance information can be obtained by observing the control voltage Vc of the control terminal of the VCO 130. Therefore, this embodiment does not require an additional design of the demodulation circuit. In addition, the locking speed of the phase locked loop 150 is usually much higher than the physical disturbance to be detected, so the output frequency of the VCO 130 is fixed to the reference frequency. Therefore, there is a clear advantage in spectrum use efficiency.

In FIG. 2B, another possible implementation of PLL 150 further includes a frequency divider 240. The frequency divider 240 divides the output oscillating signal of the VCO 130 and sends the divided result to the PFD 210. The PFD 210 compares the divided oscillating signal with the reference frequency Ref. The rest of the action is similar to Figure 2A. Therefore, the details are omitted here.

Figure 3 is a block diagram showing a non-contact disturbance sensing device of another embodiment of the present disclosure. Referring to FIG. 3 , the non-contact disturbance sensing device 300 includes an antenna 310 , a voltage controlled oscillator 330 , a processing unit 340 , and a phase locked loop 350 .

In this embodiment, the antenna 310 has a function of receiving a wireless signal and transmitting a wireless signal. The output oscillating signal of the VCO 330 is transmitted to the object to be tested 380 through the antenna 310. After the object to be tested 380 reflects it, the reflected signal is injected into the VCO 330 via the antenna 310.

The function and structure of the phase-locked loop 350 and the phase-locked loop 150 in FIG. 1 are the same or similar, and thus the details thereof are omitted herein. For example, the functional blocks of the phase locked loop 150 of FIGS. 2A and 2B may also be used to implement the phase locked loop 350 of FIG.

Since the physiological parameters or motion information of the object to be tested can be detected, the above two embodiments can be applied to preservation, remote medical treatment, exercise fitness equipment and home care, speed sensing, motion sensing and the like.

Since the VCO, PLL, and processing unit can be implemented by transistors and lumped elements, the above two embodiments of the present disclosure can provide the advantages of integrated. In contrast, in the prior art, if the demodulation circuit is an analog circuit such as a delay line, it is difficult to integrate.

In the above two embodiments of the present disclosure, the VCO is controlled by the phase-locked loop to fix the output oscillating signal of the VCO. Therefore, the output oscillating signal of the VCO does not drift, and the occupied bandwidth is small. In contrast, in the prior art, the spectrum occupied by existing systems increases as the sensitivity of the VCO increases. This is because the transmitting carrier will be disturbed by the outside world. And drifting left and right. This drift amount can be regarded as a physiological parameter after being demodulated. However, if the sensitivity of the VCO is increased, the amount of frequency drift will also increase, requiring a larger channel bandwidth.

What is more, in the above two embodiments of the present disclosure, the control voltage outputted from the phase-locked loop can take out the cardiopulmonary motion information, and in principle, it is not necessary to separately design a demodulation circuit to simplify the architecture.

In the above embodiment, the receiving antenna and the transmitting antenna may also be implemented by one or more antennas.

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, 300‧‧‧ Non-contact disturbance sensing device

110, 120, 310‧‧‧ antenna

130, 330‧‧‧ Voltage Controlled Oscillator

140, 340‧ ‧ processing unit

150, 350‧‧ ‧ phase-locked loop

180, 380‧‧‧ objects to be tested

210‧‧‧ phase frequency detector

220‧‧‧Charge pump

230‧‧‧ low pass filter

240‧‧‧Delephone

1 is a block diagram showing a non-contact disturbance sensing device of one embodiment of the present disclosure.

2A and 2B are functional block diagrams showing two possible implementations of the PLL 150 in accordance with the present embodiment.

Figure 3 is a block diagram showing a non-contact disturbance sensing device of another embodiment of the present disclosure.

100. . . Non-contact disturbance sensing device

110, 120. . . antenna

130. . . Voltage controlled oscillator

140. . . Processing unit

150. . . Phase-locked loop

180. . . Object to be tested

Claims (8)

A contactless sensing device includes: at least one receiving antenna for receiving a first radio frequency signal; and at least one transmitting antenna for transmitting a second radio frequency signal to an object to be tested, the object to be tested Reflecting the second radio frequency signal into the first radio frequency signal; a voltage controlled oscillator coupled to the at least one receiving antenna and the at least one transmitting antenna, the voltage controlled oscillator outputting an oscillating signal to the at least one transmitting An antenna, and the first radio frequency signal received by the at least one receiving antenna is injected into the voltage controlled oscillator; and a phase locked loop, generating a signal according to the oscillating signal generated by the voltage controlled oscillator and a reference frequency Controlling the voltage to the voltage controlled oscillator, the control voltage locking the frequency of the oscillating signal of the voltage controlled oscillator to the reference frequency, the control voltage reflecting a disturbance information of the object to be tested. The contactless perturbation sensing device of claim 1, wherein the second radio frequency signal is different in frequency from the first radio frequency signal due to a Doppler effect generated by the perturbation information. The non-contact disturbance sensing device of claim 1, further comprising: a processing unit coupled to the voltage controlled oscillator and the phase locked loop, and evaluating the standby voltage according to the control voltage of the phase locked loop The disturbance information of the object is measured. The non-contact disturbance sensing device of claim 1, wherein the disturbance information of the object to be tested includes a physiological parameter or an action information. A non-contact disturbance sensing device includes: At least one antenna for receiving a first radio frequency signal and transmitting a second radio frequency signal, the object to be tested reflects the second radio frequency signal to become the first radio frequency signal; a voltage controlled oscillator coupled to The at least one antenna, the voltage controlled oscillator outputs an oscillating signal to the at least one antenna, and the first radio frequency signal received by the at least one antenna is injected into the voltage controlled oscillator; and a phase locked loop, according to the The oscillating signal generated by the voltage controlled oscillator and a reference frequency generate a control voltage to the voltage controlled oscillator, and the control voltage locks the oscillating signal frequency of the voltage controlled oscillator to the reference frequency, and the control voltage is Reflecting the disturbance information of one of the objects to be tested. The contactless perturbation sensing device of claim 5, wherein the second radio frequency signal is different in frequency from the first radio frequency signal due to a Doppler effect generated by the perturbation information. The non-contact disturbance sensing device of claim 5, further comprising: a processing unit coupled to the voltage controlled oscillator and the phase locked loop, and evaluating the standby voltage according to the control voltage of the phase locked loop The disturbance information of the object is measured. The non-contact disturbance sensing device of claim 5, wherein the disturbance information of the object to be tested comprises a physiological parameter or an action information.