Doppler radar device and method for suppressing narrowband interference thereof

Abstract

A Doppler radar apparatus includes a transmitting device, a receiving device, and a narrowband interference rejection device. The transmitting device is configured to transmit a first wireless signal. The receiving device is coupled to the transmitting device and configured to receive a second wireless signal to produce a first digital signal. The first digital signal includes a Doppler signal component and a narrowband interference signal component, and a bandwidth of the narrowband interference signal component is less than a bandwidth of the Doppler signal component. The narrowband interference rejection device is coupled to the receiving device and configured to perform interference rejection on the first digital signal based on the first wireless signal to reject the narrowband interference signal component in the first digital signal to produce an output digital signal.

Description

Technical Field

[0001] This invention relates to a radar technology, and more particularly to a Doppler radar device and its narrowband interference suppression method. Background Technology

[0002] Radar technology has been widely applied in various fields after years of development, such as flight radar, automotive detection radar, and physiological information detection radar. Radar can be divided into two main categories: pulse radar and continuous wave radar. Pulse radar emits periodic high-frequency pulses. Continuous wave (CW) radar emits continuous wave signals.

[0003] Narrowband interference is frequently encountered in continuous-wave Doppler radar detection. Narrowband interference can originate from objects in the environment that cause fixed-frequency variations, such as the frequency of a power supply, the frequency of a fluorescent lamp's cathode ray tube, or the rotation frequency of an electric fan. These interference sources create narrowband interference signal components in the frequency domain. When the Doppler signal used for Doppler radar detection is mixed with narrowband interference signal components, the Doppler radar is prone to false alarms. Summary of the Invention

[0004] A first aspect of the present invention provides a Doppler radar device, comprising: a transmitting device for transmitting a first radio signal; a receiving device coupled to the transmitting device for receiving a second radio signal to generate a first digital signal. The first digital signal includes a Doppler signal component and a narrowband interference signal component, wherein the bandwidth of the narrowband interference signal component is smaller than the bandwidth of the Doppler signal component; and a narrowband interference suppression device coupled to the receiving device for performing interference suppression on the first digital signal to suppress the narrowband interference signal component in the first digital signal, thereby generating an output digital signal, wherein the narrowband interference suppression device includes: a tapped delay line for obtaining a delayed digital signal based on the first digital signal; and an interference estimation device coupled to the tapped delay line, configured to: generate an interference prediction signal based on the delayed digital signal and a plurality of weighting coefficients; update the weighting coefficients based on an error signal; and determine an adjustment signal based on the first digital signal, the weighting coefficients, and the error signal, wherein the interference prediction signal corresponds to the narrowband interference signal component, and wherein the adjustment signal corresponds to the strength of the interference suppression.

[0005] A second aspect of the present invention provides a Doppler radar device, comprising: a transmitting device for transmitting a first wireless signal; a receiving device coupled to the transmitting device for receiving a second wireless signal to generate a first digital signal, wherein the first digital signal includes a Doppler signal component and a narrowband interference signal component, and the bandwidth of the narrowband interference signal component is less than the bandwidth of the Doppler signal component; and a narrowband interference suppression device coupled to the receiving device for performing interference suppression on the first digital signal to suppress the narrowband interference signal component in the first digital signal, thereby generating an output digital signal, wherein the narrowband interference suppression device includes: a high-pass filter for filtering out the Doppler signal component of the first digital signal to generate an interference tracking digital signal; and an interference estimation device configured to: obtain a plurality of weighting coefficients based on the interference tracking digital signal, wherein the weighting coefficients are related to the interference frequency of the narrowband interference signal component; obtain an error signal based on the interference tracking digital signal and the weighting coefficients; update the weighting coefficients based on the error signal; and determine an adjustment signal based on the weighting coefficients, wherein the adjustment signal corresponds to the strength of the interference suppression.

[0006] A third aspect of this invention provides a narrowband interference suppression method applicable to a Doppler radar device including a transmitting device, a receiving device, and a narrowband interference suppression device. The narrowband interference suppression device includes a tapped delay line and an interference estimation device. The narrowband interference suppression method includes: transmitting a first radio signal; receiving a second radio signal to generate a first digital signal, wherein the first digital signal includes a Doppler signal component and a narrowband interference signal component, and the bandwidth of the narrowband interference signal component is less than the bandwidth of the Doppler signal component; and performing interference suppression on the first digital signal to suppress the narrowband interference signal component in the first digital signal, thereby generating an output digital signal. The interference suppression includes: obtaining a delayed digital signal based on the first digital signal; generating an interference prediction signal based on the delayed digital signal and multiple weighting coefficients; updating the weighting coefficients based on an error signal; and determining an adjustment signal based on the first digital signal, the weighting coefficients, and the error signal, wherein the interference prediction signal corresponds to the narrowband interference signal component, and the adjustment signal corresponds to the intensity of the interference suppression.

[0007] A fourth aspect of this invention provides a narrowband interference suppression method applicable to a Doppler radar device including a transmitting device, a receiving device, and a narrowband interference suppression device. The narrowband interference suppression device includes a high-pass filter and an interference estimation device. The narrowband interference suppression method includes: transmitting a first radio signal; receiving a second radio signal to generate a first digital signal, wherein the first digital signal includes a Doppler signal component and a narrowband interference signal component, and the bandwidth of the narrowband interference signal component is less than the bandwidth of the Doppler signal component; and performing interference suppression on the first digital signal to suppress the narrowband interference signal component in the first digital signal, thereby generating an output digital signal. The interference suppression includes: filtering out the Doppler signal component of the first digital signal to generate an interference tracking digital signal; obtaining multiple weighting coefficients based on the interference tracking digital signal, wherein those weighting coefficients are related to the interference frequency of the narrowband interference signal component; obtaining an error signal based on the interference tracking digital signal and those weighting coefficients; updating those weighting coefficients based on the error signal; and determining an adjustment signal based on those weighting coefficients, wherein the adjustment signal corresponds to the intensity of the interference suppression.

[0008] To make the above features of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings for detailed explanation. Attached Figure Description

[0009] Figure 1A This is a schematic diagram of a Doppler radar device according to an embodiment of the present invention.

[0010] Figure 1B This is a flowchart of a narrowband interference suppression method according to an embodiment of the present invention.

[0011] Figure 2 This is a schematic diagram of the Doppler signal components and narrowband interference signal components in an embodiment of the present invention.

[0012] Figure 3A This is a schematic diagram of a narrowband interference suppression device according to the first embodiment of the present invention.

[0013] Figure 3B This is a flowchart of an interference suppression method according to a first embodiment of the present invention.

[0014] Figure 4A This is a schematic diagram of a narrowband interference suppression device according to a second embodiment of the present invention.

[0015] Figure 4B This is a flowchart of an interference suppression method according to a second embodiment of the present invention.

[0016] Figure 5 This is a schematic diagram of an interference estimation device according to a second embodiment of the present invention.

[0017] Figure 6A This is a schematic diagram of a first notch filter according to a second embodiment of the present invention.

[0018] Figure 6B This is a schematic diagram of the frequency response of a first notch filter according to a second embodiment of the present invention.

[0019] Figure 7A This is a schematic diagram of a second notch filter according to a second embodiment of the present invention.

[0020] Figure 7B This is a schematic diagram of the frequency response of a second notch filter according to a second embodiment of the present invention.

[0021] Symbol Explanation 100: Doppler radar device 110: Launching device 120: Receiving device 130, 300, 400: Narrowband interference suppression devices 140: Motion Detector 310: Tap Delay Line 320, 420: Interference estimation device 321: Filtering Block 322, 510: Coefficient Update Module 330, 340, 350, 503, 611, 612, 613, 711, 712, 713, AD: Adders 360, 370, 504, 505, 620, 621, 622, 623, 721, 722, 723, MP: Multipliers 410: High-pass filter 430, 440: Notch filters 501, 502, 601, 602, 603, 604, 701, 702, 703, 704, D: Delayed taps Obj: Object WS1: First wireless signal WS2: Second wireless signal TA: Transmitter Antenna PA: Power Amplifier LO: Local Oscillator f c Clock frequency RA: Receiver Antenna LNA: Low Noise Amplifier MX: Mixer ADC: Analog-to-Digital Converter x(n): First digital signal M, Integer x D (n), x D (n-1), x D (n-2), x D (n-M+2), x D (n-M+1) Delayed digital signal y1(n), y g (n), y 1g (n), y1(n-1), y g (n-1), y 1g (n-1), y1(n-2), y g (n-2), y 1g (n-2), x(n-1), x(n-2), x Tr (n-1), x Tr (n-2): Digital signal y(n): Output digital signal x Tr (n): Interference tracking digital signal g(n): Adjustment signal , : numerical value e(n): Error signal w0(n), w1(n), w2(n), w M-2 (n), w M-1 (n), v(n), w1(n+1), w2(n+1), , Weighting coefficient , Linear iteration coefficients DP: Doppler signal components NB1, NB2: Narrowband interference signal components f I Interference frequency BW, BW1, BW2: Bandwidth E: Energy A: Amplitude f: Frequency S101, S102, S103, S301, S302, S303, S304, S401, S402, S403, S404: Steps Tracking coefficient Adjust parameters , , c, , : Parameters r: Reference value r th Threshold , :vector , , Matrix Detailed Implementation

[0022] Figure 1A This is a schematic diagram of a Doppler radar device according to an embodiment of the present invention. Please refer to... Figure 1A The Doppler radar device 100 includes a transmitting device 110, a receiving device 120, and a narrowband interference suppression device 130. The Doppler radar device 100 can be applied to fields such as meteorology, speed measurement, reversing, terrain detection, military, or physiological detection. In this embodiment, the Doppler radar device is used to detect the spatial information of object Obj in a field.

[0023] Transmitting device 110 is used to transmit a first wireless signal WS1. Receiving device 120 is coupled to transmitting device 110. Receiving device 120 is used to receive a second wireless signal WS2 and generate a first digital signal x(n). Narrowband interference suppression device 130 is coupled to receiving device 120. Narrowband interference suppression device 130 is used to perform interference suppression and generate an output digital signal y(n). The detailed operation of interference suppression by narrowband interference suppression device 130 will be described in subsequent embodiments.

[0024] In one embodiment, the Doppler radar device 100 further includes a motion detector 140 coupled to a narrowband interference suppression device 130. The motion detector 140 can determine the movement of object Obj based on the output digital signal y(n). Specifically, the second radio signal WS2 received by the receiving device 120 may include a reflected signal generated by the first radio signal WS1 transmitted by the transmitting device 110 after being reflected by object Obj. The narrowband interference suppression device 130 or the motion detector 140 may be a chip, processor, microcontroller, application-specific integrated circuit (ASIC), or any type of digital circuit. The narrowband interference suppression device 130 or the motion detector 140 may also be implemented by a computer program module in the form of a software algorithm.

[0025] In one embodiment, the transmitting device 110 includes a local oscillator LO, a power amplifier PA, and a transmitting antenna TA. The local oscillator LO is used to generate a clock frequency f. c An oscillating signal. The receiving end of the power amplifier PA is coupled to a local oscillator LO to receive the oscillating signal and provide a radio frequency signal. The transmitting end antenna TA is coupled to the power amplifier PA and is controlled by the power amplifier PA to convert and transmit the radio frequency signal into a first wireless signal WS1 transmitted by the transmitting device 110.

[0026] In one embodiment, the receiving device 120 includes a receiving antenna RA, a low-noise amplifier LNA, a mixer MX, and an analog-to-digital converter ADC. The receiving antenna RA receives a second wireless signal WS2 received by the receiving device 120 to generate a first analog signal. The low-noise amplifier LNA is coupled to the receiving antenna RA and amplifies the first analog signal to become an amplified analog signal. The mixer MX is coupled to the low-noise amplifier LNA and a local oscillator LO in the transmitting device 110. The mixer MX operates according to a clock frequency f from an oscillation signal in the local oscillator LO. c The amplified analog signal is mixed to generate an analog received signal. An analog-to-digital converter (ADC) coupled to a mixer MX is used to convert the analog received signal into a first digital signal x(n).

[0027] To facilitate understanding of the operational flow of the embodiments of the present invention, numerous embodiments will be used to describe in detail the operation of the Doppler radar device 100 in the embodiments of the present invention. Below, the narrowband interference suppression method described in the embodiments of the present invention will be explained in conjunction with the various components in the Doppler radar device 100. The various processes of this method may be adjusted according to the implementation situation, and are not limited thereto.

[0028] Figure 1B This is a flowchart of a narrowband interference suppression method according to an embodiment of the present invention. Please refer to... Figure 1B , Figure 1B Narrowband interference suppression method is applicable Figure 1A The Doppler radar device 100 is shown in the illustration.

[0029] In step S101, transmitter 110 transmits a first wireless signal WS1 to detect object Obj in the field. In step S102, receiver 120 receives a second wireless signal WS2 and generates a first digital signal x(n). In step S103, narrowband interference suppression device 130 suppresses narrowband interference signal components in the first digital signal x(n) to generate an output digital signal y(n).

[0030] Figure 2This is a schematic diagram of the Doppler signal components and narrowband interference signal components in an embodiment of the present invention. Figure 2 The vertical axis represents energy E, and the horizontal axis represents frequency f. Specifically, the first digital signal x(n) may include a Doppler signal component DP and a narrow-band interference signal component, for example... Figure 2 The diagram illustrates narrowband interference signal components NB1 and / or NB2. Narrowband interference signal component NB1 corresponds to the interference frequency f. I The narrowband interference signal component NB2 corresponds to the interference frequency 2f. I The Doppler signal component DP has a bandwidth BW. The narrowband interference signal component NB1 has a bandwidth BW1. The narrowband interference signal component NB2 has a bandwidth BW2. Generally speaking, the bandwidth BW1 of the narrowband interference signal component NB1 or the bandwidth BW2 of the narrowband interference signal component NB2 is smaller than the bandwidth BW of the Doppler signal component DP.

[0031] Figure 3A This is a schematic diagram of a narrowband interference suppression device 130 according to a first embodiment of the present invention. Figure 3A The narrowband interference suppression device 300 shown is Figure 1A This is one embodiment of the narrowband interference suppression device 130, but is not limited thereto.

[0032] Please refer to Figure 3A The narrowband interference suppression device 300 includes a tapped delay line (TDL) 310 and an interference estimation device 320. The tapped delay line 310 is used to obtain a delayed digital signal x based on a first digital signal x(n). D (n). Tapped delay line 310 includes multiple delay taps D. Interference estimation device 320 is coupled to tapped delay line 310. Interference estimation device 320 can receive a first digital signal x(n) and a delayed digital signal x. D The interference estimation device 320 generates a digital signal y1(n) and an adjustment signal g(n) from the error signal e(n). The interference estimation device 320 includes two parts: a filtering block 321 and a coefficient update module 322. The filtering block 321 includes M-1 delay taps D, M multipliers MP, and M-1 adders AD, where M is an integer. The coefficient update module 322 stores M weighted coefficients w0(n), w1(n), w2(n) ~ w M-2 (n), w M-1 (n), and based on the first digital signal x(n) and the delayed digital signal x D The weighting coefficients w0(n), w1(n), and w2(n) are updated iteratively using the error signal e(n) and the error signal e(n). M-2 (n), w M-1 (n).

[0033] Figure 3B This is a flowchart illustrating interference suppression according to a narrowband interference suppression method based on a first embodiment of the present invention. Please refer to it. Figure 3A and Figure 3B Narrowband interference suppression device 300 can perform Figure 3B The flowchart for interference suppression.

[0034] In step S301, the tapped delay line 310 obtains the delayed digital signal x based on the first digital signal x(n). D (n). In step S302, the filtering block 321 in the interference estimation device 320 calculates the delay digital signal x. D (n) and multiple weighting coefficients w0(n), w1(n), w2(n) ~ w M-2 (n), w M-1 (n) Generates an interference prediction signal y1(n). In step S303, the coefficient update module 322 in the interference estimation device 320 updates the weighting coefficients w0(n), w1(n), w2(n) to w1(n) according to the error signal e(n). M-2 (n), w M-1 (n). In step S304, the coefficient update module 322 in the interference estimation device 320 updates the coefficients based on the first digital signal x(n) and the weighted coefficients w0(n), w1(n), w2(n) ~ w M-2 (n), w M-1 The adjustment signal g(n) is determined by the error signal e(n) and the error signal e(n), where the interference prediction signal y1(n) corresponds to the narrowband interference signal component, for example... Figure 2 The narrowband interference signal component NB1 or narrowband interference signal component NB2 is in the signal, where the adjustment signal g(n) corresponds to the strength of interference suppression.

[0035] Specifically, the interference estimation device 320 is a linear predictive filter, and the interference estimation device 320 gradually updates the weighting coefficients w0(n), w1(n), w2(n) to w using a linear iterative method. M-2 (n), w M-1 (n).

[0036] The linear iterative process of the interference estimation device 320 can be represented by the following formula and can be implemented by the coefficient update module 322:

[0037] (Equation 1-1)

[0038] ,

[0039] (Equation 1-2)

[0040] In the above formula , Let x(n) be the linear iterative coefficients corresponding to the first digital signal x(n), and let the parameter be... , c is used to adjust the weighting coefficients w0(n), w1(n), w2(n) ~ w M-2 (n), w M-1 The update speed of (n) and the magnitude of the numerical change in each update are important considerations. It should be noted that the linear iterative calculation of the interference estimation device 320 can be implemented using a software program module or through hardware circuitry.

[0041] In one embodiment, the narrowband interference suppression device 300 further includes adders 330, 340, 350, multiplier 360, and multiplier 370. Multiplier 360 is coupled to the interference estimation device 320. Multiplier 360 is used to multiply the interference prediction signal y1(n) with the adjustment signal g(n) to generate the interference suppression signal y g (n). Adder 330 is coupled to multiplier 360. Adder 330 is used to subtract the interference suppression signal y from the first digital signal x(n). g The first digital signal x(n) is subtracted from the interference prediction signal y1(n) to generate an output digital signal y(n). Adder 340 is coupled to interference estimation device 320. Adder 340 is used to subtract the interference prediction signal y1(n) from the first digital signal x(n) to generate an error signal e(n). Multiplier 370 is coupled to adder 340 and adder 350. Multiplier 370 is used to multiply the error signal e(n) by a tracking coefficient. And fed back to the first digital signal x(n) through adder 350, where the tracking coefficient Used to adjust the interference suppression signal y g The frequency selection range of (n). Specifically, the tracking coefficients. It is a number between 0 and 1, the tracking coefficient. The weight of the negative feedback of the adjustable error signal e(n), i.e., the strength of the narrowband interference prediction error feedback, is thus determined by the tracking coefficient. The frequency range selectivity for interference estimation can be adjusted.

[0042] In one embodiment, the interference estimation device 320 estimates the interference based on the weighting coefficients w0(n), w1(n), w2(n), w M-2 (n), w M-1 (n) Determine the reference value r. Specifically, the reference value r can be calculated using the following formula:

[0043]

[0044] In one embodiment, the interference estimation device 320 responds when the reference value r is greater than or equal to the threshold r. th According to the adjusted parameters The adjustment signal g(n) is updated to enhance interference suppression. In one embodiment, the interference estimation device 320 responds when the reference value r is less than a threshold value r. th According to the adjusted parameters The adjustment signal g(n) is updated to reduce this interference suppression. Specifically, the adjustment signal g(n) can be updated using the following formula:

[0045]

[0046] It is worth noting that the value of the adjustment signal g(n) is between 0 and 1. The adjustment signal g(n) reflects the relationship between the intensity of the Doppler signal component and the intensity of the narrowband interference signal component in the first digital signal x(n). A larger value of the adjustment signal g(n) indicates a stronger narrowband interference signal component, and the interference prediction signal y1(n) generated by the interference estimation device 320 will be significantly subtracted from the first digital signal x(n). In other words, a larger value of the adjustment signal g(n) corresponds to a stronger interference suppression effect. Conversely, a smaller value of the adjustment signal g(n) means that it is not necessary to suppress the narrowband interference signal component in the first digital signal x(n) significantly. Therefore, by reflecting the relationship between the intensity of the Doppler signal component and the intensity of the narrowband interference signal component in the digital signal using the adjustment signal g(n), the intensity of interference suppression can be adaptively adjusted to reduce the false alarm rate of Doppler radar detection caused by narrowband interference signals, further improving the accuracy of Doppler radar detection.

[0047] Figure 4A This is a schematic diagram of a narrowband interference suppression device 130 according to a second embodiment of the present invention. Figure 4A The narrowband interference suppression device 400 shown is Figure 1A This is one embodiment of the narrowband interference suppression device 130, but is not limited thereto.

[0048] Please refer to Figure 4A The narrowband interference suppression device 400 includes a high-pass filter 410, an interference estimation device 420, a first notch filter 430, and a second notch filter 440.

[0049] Figure 4B This is a flowchart illustrating interference suppression according to a narrowband interference suppression method based on a second embodiment of the present invention. Please refer to it. Figure 4A and Figure 4B Narrowband interference suppression device 400 can perform Figure 4B The flowchart for interference suppression.

[0050] In step S401, the high-pass filter 410 filters out the low-frequency components of the first digital signal x(n), such as Doppler signal components, and generates an interference tracking digital signal x. Tr (n). In step S402, the interference estimation device 420 calculates the interference tracking digital signal x. Tr (n) Obtain multiple weighting coefficients w1(n) and w2(n), wherein these weighting coefficients w1(n) and w2(n) are related to the interference frequency of the narrowband interference signal component, and track the digital signal x according to the interference. Tr The interference estimation device 420 obtains an error signal e(n) based on the weighting coefficients w1(n) and w2(n). In step S403, the interference estimation device 420 updates the weighting coefficients w1(n) and w2(n) according to the error signal e(n). In step S404, the adjustment signal g(n) is determined based on the weighting coefficients w1(n) and w2(n), wherein the adjustment signal g(n) corresponds to the intensity of interference suppression.

[0051] Specifically, the interference estimation device 420 is a linear prediction filter, and the interference estimation device 420 updates the weighting coefficients w1(n) and w2(n) step by step using a linear iterative method.

[0052] The linear prediction iteration process of the interference estimation device 420 can be represented by the following formula:

[0053] (Equation 2-1)

[0054] (Equation 2-2)

[0055] (Equation 2-3)

[0056] (Equation 2-4)

[0057] = (Equation 2-5)

[0058] (Equation 2-6)

[0059] initial value (Equation 2-7)

[0060] In the above formula, vector The elements therein correspond to the interference tracking digital signal x. Tr (n-1),x Tr (n-2) linear disturbance prediction signal. Matrix Each element is a linear iteration coefficient. Vector The elements within represent the weighting coefficients w1(n) and w2(n) respectively, used to update the weights. Parameters Used to adjust the update speed of the weighting coefficients w1(n) and w2(n) and the magnitude of the numerical change in each update. Parameters Used to adjust the interference tracking digital signal x Tr (n-1), x Tr The initial values ​​of (n-2) are weights that influence the linear iteration. Specifically, the weighting coefficients w1(n), w2(n), and filter coefficients v(n) are related to the interference frequency of the narrowband interference signal component. In one embodiment, the weighting coefficients w1(n), w2(n) are related to the interference dominant frequency (first harmonic frequency, e.g., f) in the narrowband interference signal component. I The parameters corresponding to ) are the filter coefficients v(n), which are the second harmonic frequency (e.g., 2f) of the interference signal component in the narrowband interference signal. I The corresponding parameters. It should be noted that the linear iterative calculation of the interference estimation device 420 can be implemented using a software program module or through hardware circuitry.

[0061] Figure 5 This is a schematic diagram of the interference estimation device 420 according to the second embodiment of the present invention. Please refer to... Figure 5 The interference estimation device 420 includes a delay tap 501, a delay tap 502, an adder 503, a multiplier 504, a multiplier 505, and a coefficient update module 510.

[0062] In the aforementioned formula, (Equation 2-1) can be implemented by the following steps: digital signal x Tr (n) The digital signal x is generated by delaying the signal through delay tap 501. Tr (n-1). Digital signal x Tr (n-1) is then delayed by the delay tap 502 to generate the digital signal x. Tr (n-2). The multiplier 504 will multiply the digital signal x... Tr The digital signal w1(n) is obtained by multiplying (n-1) and the weighting coefficient w1(n). Tr (n-1). The multiplier 505 will multiply the digital signal x... Tr The digital signal w2(n) is obtained by multiplying (n-2) and the weighting coefficient w2(n). Tr (n-2). Adder 503 converts the digital signal x Tr (n) minus the result of the multiplier 504 w1(n) x Tr The result of the operation of (n-1) and multiplier 505 is w2(n) x Tr(n-2) generates an error signal e(n). The coefficient update module 510 can be used to implement equations (2-2) to (2-7) in the aforementioned formulas to save and update the digital signal x. Tr (n-1), x Tr (n-2), weighting coefficients w1(n), w2(n) and error signal e(n), and generate filter coefficients v(n) and adjustment signal g(n).

[0063] In one embodiment, weighting coefficients w1(n) and w2(n) are used as filter coefficients of the first notch filter 430. The first notch filter 430 filters out the first interference frequency of the narrowband interference signal component based on the filter coefficients w1(n) and w2(n), for example... Figure 2 The interference frequency f shown in the figure I The second notch filter 440 filters out the second interference frequency of the narrowband interference signal component based on the filter coefficients v(n), for example... Figure 2 The interference frequency 2f shown in the figure I The interference estimation device 420 adjusts the first notch filter 430 to filter out the first interference frequency of the narrow-band interference signal component according to the adjustment signal g(n). The interference estimation device 420 adjusts the second notch filter 440 to filter out the second interference frequency of the narrow-band interference signal component according to the adjustment signal g(n) and generates an output digital signal y(n).

[0064] In one embodiment, only the first notch filter 430 may be used. The interference estimation device 420 adjusts the first interference frequency f of the first notch filter 430 to filter out narrowband interference signal components according to the adjustment signal g(n). I Then, the generated digital signal y1(n) is used as the output digital signal y(n).

[0065] In one embodiment, the interference estimation device 420 determines a reference value r based on the filter coefficients w1(n) and w2(n). The interference estimation device 420 responds when the reference value r is greater than or equal to a threshold r. th According to the adjusted parameters The signal g(n) is updated and adjusted to enhance interference suppression. The interference estimation device 420 responds when the reference value r is less than the threshold r. th According to the adjusted parameters The adjustment signal g(n) is updated to reduce this interference suppression. Specifically, the reference value r can be calculated using the following formula:

[0066]

[0067] The adjustment signal g(n) can be updated using the following formula:

[0068]

[0069] In the above formula , These represent the maximum and minimum allowed values ​​for the default adjustment signal g(n). It should be noted that the value of the adjustment signal g(n) is between 0 and 1, therefore the maximum value... and minimum value The value is also between 0 and 1. The digital signal x is tracked by interference filtered through a high-pass filter. Tr The Doppler radar device and its interference suppression method provided in this invention can reduce false alarms caused by narrow-band interference signals in Doppler radar detection and further improve the accuracy of Doppler radar detection. The adjustment signal g(n) after passing through the interference estimation device is used to linearly predict the narrow-band interference signal component in the digital signal, and the interference frequency corresponding to the narrow-band interference signal component is suppressed or filtered out by the notch filter.

[0070] Figure 6A This is a schematic diagram of a first notch filter 430 according to a second embodiment of the present invention. Please refer to... Figure 6A The first notch filter 430 includes delay taps 601, 602, 603, and 604, adders 611, 612, and 613, multipliers 620, 621, 622, and 623.

[0071] The first digital signal x(n) is delayed to the digital signal x(n-1) by delay tap 601. The digital signal x(n-1) is then delayed to the digital signal x(n-2) by delay tap 602. Multiplier 623 multiplies the digital signal y1(n) with the adjustment signal g(n) to obtain the digital signal y. 1g (n) = y1(n) g(n). Digital signal y 1g (n) is delayed to a digital signal y after passing through delay tap 604. 1g (n-1). Digital signal y 1g (n-1) is then delayed to a digital signal y by the delay tap 603. 1g (n-2).

[0072] Adder 612 subtracts digital signal y from digital signal x(n-1). 1g (n-1), then multiplied by multiplier 621 and multiplied by weighting coefficients w1(n). Multiplier 622 multiplies the digital signal y 1g (n-2) is then multiplied by the adjustment signal g(n) to obtain the digital signal g(n)y. 1g (n-2). Adder 611 subtracts the result g(n)y from multiplier 622 from the digital signal x(n-2). 1g (n-2) yields x(n-2)-g(n)y1g (n-2). Multiplier 620 multiplies the result of adder 611 by the weighting coefficient w2(n).

[0073] Adder 613 subtracts the result of multiplier 621 w1(n)[x(n-1)-y from the first digital signal x(n). 1g (n-1)] and the result of subtracting the multiplier 620, w2(n) [x(n-2)-g(n)y 1g (n-2)] Generates a digital signal y1(n)=x(n)-w1(n) [x(n-1)-y 1g (n-1)]-w2(n) [x(n-2)-g(n)y 1g (n-2)]. Therefore, the first notch filter 430 can filter the first digital signal x(n) corresponding to the interference frequency f. I Narrowband interference signal components are filtered out or suppressed.

[0074] Figure 6B This is a schematic diagram of the frequency response of the first notch filter 430 according to the second embodiment of the present invention. Figure 6B The vertical axis represents the frequency magnitude response A, and the horizontal axis represents the frequency f. From Figure 6B It can be seen that at the interference frequency f I Since the intensity of the adjacent signal is less than 0 dB, the first notch filter 430 can filter out or suppress the signal in the first digital signal x(n) corresponding to the interference frequency f. I Narrowband interference signal components.

[0075] Figure 7A This is a schematic diagram of the second notch filter 440 according to the second embodiment of the present invention. Please refer to... Figure 7A The second notch filter 440 includes delay taps 701, 702, 703, and 704, adders 711, 712, and 713, multipliers 721, 722, and 723.

[0076] The digital signal y1(n) is delayed to the digital signal y1(n-1) by delay tap 701. The digital signal y1(n-1) is then delayed to the digital signal y1(n-2) by delay tap 702. The multiplier 723 multiplies the output digital signal y(n) with the adjustment signal g(n) to obtain the digital signal y1(n-1). g (n) = y(n) g(n). digital signaly g (n) is delayed to a digital signal y after passing through delay tap 704. g (n-1). Digital signal y g(n-1) is then delayed to a digital signal y by the delay tap 703. g (n-2).

[0077] Adder 712 subtracts digital signal y from digital signal y1(n-1). g (n-1), then multiplied by multiplier 721 and multiplied by weighting coefficients v(n). Multiplier 722 multiplies the digital signal y. g (n-2) is then multiplied by the adjustment signal g(n) to obtain the digital signal g(n). g (n-2). Adder 711 subtracts the result g(n) from multiplier 722 from the digital signal y1(n-2). g (n-2) gives y1(n-2) - g(n) y g (n-2).

[0078] Adder 713 subtracts the result v(n) from multiplier 721 from digital signal y1(n) [y1(n-1)-y g (n-1)] and the result of subtracting adder 711, y1(n-2)-g(n)y g (n-2) Generates the output digital signal y(n)=y1(n)-v(n)[y1(n-1)-y g (n-1)]-[y1(n-2)-g(n)y g (n-2)]. Therefore, the second notch filter 430 can filter the first digital signal x(n) or digital signal y1(n) corresponding to the interference frequency 2f. I Narrowband interference signal components are filtered out or suppressed.

[0079] Figure 7B This is a schematic diagram of the frequency response of the second notch filter 440 according to the second embodiment of the present invention. Figure 7B The vertical axis represents the frequency intensity response A, and the horizontal axis represents the frequency f. From Figure 7B It can be seen that at the interference frequency 2f I Since the intensity of the adjacent signal is less than 0 dB, the second notch filter 440 can filter out or suppress the signal corresponding to the interference frequency 2f in the first digital signal x(n) or digital signal y1(n). I Narrowband interference signal components.

[0080] It is worth mentioning that, in some embodiments, the narrowband interference suppression device 400 may also use multiple notch filters to suppress or filter out multiple interference frequencies in the narrowband interference signal components. For example, multiple notch filters may be used to filter out interference frequencies f respectively. I 2f I 3f I …and so on, and not limited to using one or two notch filters.

[0081] In summary, the embodiments of the present invention linearly predict the narrowband interference signal components in the digital signal and adaptively adjust the interference suppression strength by adjusting the relationship between the intensity of the Doppler signal components and the intensity of the narrowband interference signal components in the adjusted signal. Furthermore, the embodiments of the present invention linearly predict the narrowband interference signal components in the digital signal using a high-pass filtered interference tracking digital signal and utilize a notch filter to suppress or filter out the interference frequencies corresponding to the narrowband interference signal components. Therefore, the Doppler radar device and interference suppression method provided by the embodiments of the present invention can reduce false alarms caused by narrowband interference signals in Doppler radar detection, further improving the accuracy of Doppler radar detection.

[0082] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the claims.

Claims

1. A Doppler radar device, characterized in that, include: A transmitting device for transmitting a first wireless signal; A receiving device, coupled to the transmitting device, is used to receive a second wireless signal and generate a first digital signal, wherein the first digital signal includes a Doppler signal component and a narrowband interference signal component, and the bandwidth of the narrowband interference signal component is smaller than the bandwidth of the Doppler signal component. as well as A narrowband interference suppression device, coupled to the receiving device, is used to suppress interference in the first digital signal to suppress the narrowband interference signal component in the first digital signal, thereby generating an output digital signal. The narrowband interference suppression device includes: A tapped delay line is used to obtain a delayed digital signal based on the first digital signal; as well as An interference estimation device, coupled to the tapped delay line, is configured to: An interference prediction signal is generated based on the delayed digital signal and multiple weighting coefficients; The weighting coefficients are updated based on an error signal; and An adjustment signal is determined based on the first digital signal, the weighting coefficients, and the error signal, wherein the interference prediction signal corresponds to the narrowband interference signal component, and the adjustment signal corresponds to the strength of the interference suppression.

2. The Doppler radar device as described in claim 1, characterized in that, The narrowband interference suppression device further includes: A first multiplier, coupled to the interference estimation device, is used to multiply the interference prediction signal by the adjustment signal to generate an interference suppression signal; and A first adder, coupled to the first multiplier, is used to subtract the interference suppression signal from the first digital signal to generate the output digital signal.

3. The Doppler radar device as described in claim 2, characterized in that, The narrowband interference suppression device further includes: A second adder, coupled to the interference estimation device, is used to subtract the interference prediction signal from the first digital signal to generate the error signal; and A second multiplier, coupled to the second adder, is used to multiply the error signal by a tracking coefficient and feed it back to the first digital signal, wherein the tracking coefficient is used to adjust the frequency selection range of the interference suppression signal.

4. A Doppler radar device, characterized in that, include: A transmitting device for transmitting a first wireless signal; A receiving device, coupled to the transmitting device, is used to receive a second wireless signal and generate a first digital signal, wherein the first digital signal includes a Doppler signal component and a narrowband interference signal component, and the bandwidth of the narrowband interference signal component is smaller than the bandwidth of the Doppler signal component. as well as A narrowband interference suppression device, coupled to the receiving device, is used to suppress interference in the first digital signal to suppress the narrowband interference signal component in the first digital signal, thereby generating an output digital signal; The narrowband interference suppression device includes: A high-pass filter is used to filter out the Doppler signal component of the first digital signal to generate an interference tracking digital signal; as well as An interference estimation device, configured to: Multiple weighting coefficients are obtained based on the interference tracking digital signal, wherein these weighting coefficients are related to an interference frequency of the narrowband interference signal component, and an error signal is obtained based on the interference tracking digital signal and these weighting coefficients. Update these weighting coefficients based on the error signal; An adjustment signal is determined based on these weighting coefficients, wherein the adjustment signal corresponds to the strength of the interference suppression.

5. The Doppler radar device as described in claim 4, characterized in that, These weighting coefficients include multiple first filter coefficients, and the narrowband interference suppression device further includes: A first notch filter is used to filter out the first interference frequency of the narrowband interference signal component according to the first filter coefficients, wherein The interference estimation device is further configured to: The first notch filter is adjusted according to the adjustment signal to filter out the first interference frequency of the narrowband interference signal component and generate the output digital signal.

6. The Doppler radar device as described in claim 4, characterized in that, The weighting coefficients further include multiple first filter coefficients and at least one second filter coefficient, and the narrowband interference suppression device further includes: A first notch filter, used to filter out a first interference frequency of the narrowband interference signal component according to the first filter coefficients; and A second notch filter is used to filter out the second interference frequency of the narrowband interference signal component according to at least one of the second filter coefficients, wherein The interference estimation device is further configured to: The first interference frequency at which the first notch filter filters out the narrowband interference signal component is adjusted according to the adjustment signal; and The second notch filter is adjusted according to the adjustment signal to filter out the second interference frequency of the narrowband interference signal component and generate the output digital signal.

7. The Doppler radar device as described in claim 1 or 4, characterized in that, The interference estimation device is further configured to: A reference value is determined based on these weighting factors; In response to the reference value being greater than or equal to a threshold, the adjustment signal is updated according to an adjustment parameter to enhance the interference suppression; and If the reference value is less than the threshold, the adjustment signal is updated according to the adjustment parameter to reduce the interference suppression.

8. The Doppler radar device as described in claim 1 or 4, characterized in that, Including: A motion detector coupled to the narrowband interference suppression device, wherein the motion detector determines the movement of an object based on the output digital signal, wherein the second wireless signal includes a reflected signal generated by the first wireless signal reflected by the object.

9. The Doppler radar device as described in claim 1 or 4, characterized in that, The launching device includes: A local oscillator is used to generate an oscillation signal including a clock frequency; A power amplifier, the receiver of which is coupled to the local oscillator to receive the oscillation signal and to provide a radio frequency signal; and A transmitting antenna is coupled to the power amplifier to convert and transmit the radio frequency signal into the first wireless signal.

10. The Doppler radar device as described in claim 9, characterized in that, The receiving device includes: A receiving antenna receives the second wireless signal to generate a first analog signal; A low-noise amplifier, coupled to the receiving antenna, amplifies the first analog signal to become an amplified analog signal. A mixer, coupled to the low-noise amplifier and the local oscillator in the transmitting device, wherein the mixer mixes the amplified analog signal according to the clock frequency of the oscillation signal from the local oscillator, thereby generating an analog received signal; and An analog-to-digital converter, coupled to the mixer, is used to convert the analog received signal into the first digital signal.

11. A narrowband interference suppression method, characterized in that, The narrowband interference suppression method, applicable to a Doppler radar device, includes: Transmit a first wireless signal; A first digital signal is generated by receiving a second wireless signal, wherein the first digital signal includes a Doppler signal component and a narrowband interference signal component, and the bandwidth of the narrowband interference signal component is smaller than the bandwidth of the Doppler signal component; and Interference suppression is performed on the first digital signal to suppress the narrowband interference signal component in the first digital signal, thereby generating an output digital signal, wherein the interference suppression includes: A delayed digital signal is obtained based on the first digital signal; An interference prediction signal is generated based on the delayed digital signal and multiple weighting coefficients; The weighting coefficients are updated based on an error signal; and An adjustment signal is determined based on the first digital signal, the weighting coefficients, and the error signal, wherein the interference prediction signal corresponds to the narrowband interference signal component, and the adjustment signal corresponds to the strength of the interference suppression.

12. The narrowband interference suppression method as described in claim 11, characterized in that, This interference suppression further includes: The interference prediction signal is multiplied by the adjustment signal to generate an interference suppression signal; and The output digital signal is generated by subtracting the interference suppression signal from the first digital signal.

13. The narrowband interference suppression method as described in claim 12, characterized in that, This interference suppression further includes: The error signal is generated by subtracting the interference suppression signal from the first digital signal; and The error signal is multiplied by a tracking coefficient and fed back to the first digital signal, wherein the tracking coefficient is used to adjust the frequency selection range of the interference suppression signal.

14. A narrowband interference suppression method, characterized in that, The narrowband interference suppression method, applicable to a Doppler radar device, includes: Transmit a first wireless signal; A first digital signal is generated by receiving a second wireless signal, wherein the first digital signal includes a Doppler signal component and a narrowband interference signal component, and the bandwidth of the narrowband interference signal component is smaller than the bandwidth of the Doppler signal component; and Interference suppression is performed on the first digital signal to suppress the narrowband interference signal component in the first digital signal, thereby generating an output digital signal, wherein the interference suppression includes: The Doppler signal component of the first digital signal is filtered out to generate an interference tracking digital signal; Multiple weighting coefficients are obtained based on the interference tracking digital signal, wherein these weighting coefficients are related to an interference frequency of the narrowband interference signal component, and an error signal is obtained based on the interference tracking digital signal and these weighting coefficients. Update the weighting coefficients based on the error signal; and An adjustment signal is determined based on these weighting coefficients, wherein the adjustment signal corresponds to the strength of the interference suppression.

15. The narrowband interference suppression method as described in claim 14, characterized in that, These weighting coefficients include multiple first filter coefficients, and the interference suppression further includes: The first interference frequency from which the narrowband interference signal component is filtered out according to the first filter coefficients; and The first interference frequency of the narrowband interference signal component is filtered out by adjusting a first notch filter according to the adjustment signal, and the output digital signal is generated.

16. The narrowband interference suppression method as described in claim 14, characterized in that, These weighting coefficients further include multiple first filter coefficients and at least one second filter coefficient, wherein the interference suppression further includes: The first interference frequency that filters out the narrowband interference signal component according to these first filter coefficients; The second interference frequency is used to filter out the narrowband interference signal component according to at least one of the second filter coefficients; The first interference frequency of a first notch filter, which filters out the narrowband interference signal component, is adjusted according to the adjustment signal; and The second notch filter is adjusted according to the adjustment signal to filter out the second interference frequency of the narrowband interference signal component and generate the output digital signal.

17. The narrowband interference suppression method as described in claim 11 or 14, characterized in that, Including: A reference value is determined based on these weighting factors; In response to the reference value being greater than or equal to a threshold, the adjustment signal is updated according to an adjustment parameter to enhance the interference suppression; and If the reference value is less than the threshold, the adjustment signal is updated according to the adjustment parameter to reduce the interference suppression.

18. The narrowband interference suppression method as described in claim 11 or 14, characterized in that, Including: The movement of an object is determined based on the output digital signal, wherein the second wireless signal includes a reflected signal generated by the first wireless signal being reflected by the object.

19. The narrowband interference suppression method as described in claim 11 or 14, characterized in that, Including: Generates an oscillating signal including a clock frequency; Receive the oscillation signal and provide a radio frequency signal; and The radio frequency signal is converted and transmitted as the first wireless signal.

20. The narrowband interference suppression method as described in claim 19, characterized in that, Including: Receive the second wireless signal to generate a first analog signal; Amplify the first analog signal to make it an amplified analog signal; The amplified analog signal is mixed with the clock frequency of the oscillation signal to generate an analog received signal; and The analog received signal is converted into the first digital signal.

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