Method for suppressing transmitter leakage signals of a multichannel transceiver and suppression circuit therefor

Abstract

The application discloses a transmitter leakage signal suppression method of a multi-channel transceiver and a suppression circuit thereof. The application opens the multiple transmitting channels of the transmitter one by one instead of simultaneously opening part or all of the multiple transmitting channels, and designs an adaptive leakage modeling and offsetting mechanism based on a known transmitting baseband sequence in cooperation with the transimpedance amplification and analog-to-digital conversion of each receiving channel of the receiver. The characteristics of the known and reproducible transmitting baseband sequence in the radar are fully utilized, the adaptive estimation of the transmitting leakage component is realized by correlating the receiving signal with the transmitting baseband sequence, and the corresponding compensation signal is generated to offset. When each transmitting channel is opened, the purpose of iterative offsetting of the transmitter leakage signal is realized. Therefore, the transmitter leakage signal carried in the radio wave received by the receiver can be suppressed without affecting the performance of the receiving front end, and the precision of radio wave ranging or speed measurement is greatly improved.

Description

Technical Field

[0001] This invention relates to a transmitter leakage signal suppression method and its suppression circuit, and more particularly to a transmitter leakage signal suppression method and its suppression circuit for a multi-channel transceiver, a radio wave ranging or speed measurement method for a PMCW automotive radar using the suppression method, a multi-channel transceiver using the suppression circuit, and a multi-transmitter multi-receiver radar system using the multi-channel transceiver. Background Technology

[0002] PMCW automotive radar can be applied to PMCW multiple-transmitter multiple-receiver radar systems to achieve ranging or speed measurement of radio waves based on transmitted and received wireless signals. PMCW (Phase-Modulated Continuous Wave) radar is a continuous wave radar system that uses pseudo-random codes (PRN / PN codes) for phase modulation. Its basic idea is to modulate a high-speed pseudo-random sequence onto the carrier phase, achieve distance measurement through correlation processing, and obtain speed information through Doppler processing. Compared to traditional FMCW radar, PMCW has advantages such as strong anti-interference capability, support for MIMO orthogonal coding, and high range resolution, thus attracting widespread attention in next-generation 4D imaging automotive millimeter-wave radar. In PMCW multiple-transmitter multiple-receiver radar systems, multiple transmitting channels operate simultaneously or quasi-simultaneously. Under high power and wide bandwidth conditions, the transmitted signal leaks to the receiving channel through various paths, including insufficient antenna isolation, on-chip parasitic coupling, package interconnects, and substrate coupling, forming transmission leakage interference. The leakage signal is usually characterized by large amplitude and strong correlation, which can easily form a significant correlation peak at the receiving end, thereby drowning out the weak target echo and reducing the dynamic range and detection performance of the system.

[0003] In existing technologies, a leakage suppression scheme based on baseband correlation cancellation—a single-channel baseband transmitter leakage suppression circuit—has been proposed to address the transmission leakage problem in PMCW radar transceivers. This scheme utilizes the known transmitted baseband signal, performs correlation operations on the mixer output signal in the receiving link, and cancels the transmission leakage components by weighted copying of the transmitted baseband sequence and injecting it into the mixer output node or subsequent baseband processing path. This method effectively suppresses leakage components highly correlated with the transmitted sequence in the baseband domain through correlation and integration operations, while preserving the target echo signal. The advantages of this type of scheme are that its suppression loop is a self-contained closed loop within the receiving channel, does not rely on additional RF isolation devices, has a relatively simple structure, a clear working mechanism, and can adaptively compensate for a certain degree of amplitude and phase errors, making it suitable for single-transmit / single-receive or single-transmit / multiple-receive applications. However, this approach inherently relies on correlation modeling and weighted cancellation of baseband signals transmitted via a single path. When multiple transmitters operate simultaneously in the system, the baseband sequences, amplitudes, phases, and leakage path characteristics of different transmission channels are independent of each other. The superimposed leakage signal at the receiver no longer satisfies the assumptions of a single correlation model. In a multi-transmitter, multi-receiver radar architecture, the above approach struggles to effectively distinguish and independently suppress leakage from multiple transmissions simultaneously, leading to a significant decrease in suppression effectiveness or even malfunction. Therefore, the applicability of this type of method in multi-channel PMCW radar transceivers is significantly limited.

[0004] To address the problem of simultaneous leakage of multiple transmitted signals in multiple-transmitter (MRT) radar systems, existing technologies have proposed a multi-channel RF front-end transmitter leakage suppression scheme. This scheme introduces copies of multiple transmitted signals into the receiver architecture and models and cancels the leakage components of each transmitted channel at the RF or IF front-end, thereby achieving simultaneous suppression of multiple transmitted leakage signals. Compared to suppression methods targeting only a single path, this scheme can process superimposed leakage signals in multi-transmitter scenarios, offering advantages suitable for multi-channel systems. However, such multi-channel transmission leakage suppression schemes typically require the introduction of complex cancellation loops and additional signal injection paths at the RF front-end, resulting in a relatively complex implementation structure. Leakage suppression at the RF front-end inevitably alters the equivalent input impedance and gain characteristics of the receiver link, adversely affecting the front-end matching conditions and noise figure, thus reducing the receiver's signal-to-noise ratio and overall sensitivity. In addition, in order to achieve independent modeling and adjustment of multiple transmitted signals, the system usually needs to be configured with additional transmit replica paths, adjustable attenuation and phase control units, which leads to a significant increase in chip area and power consumption, which is not conducive to the realization of highly integrated, low-power radar transceivers. Summary of the Invention

[0005] To address the technical problem of effectively suppressing leakage signals from multiple transmitters operating simultaneously without significantly increasing system complexity and hardware costs, this invention provides a method and circuit for suppressing transmitter leakage signals from a multi-channel transceiver, a radio wave ranging or speed measurement method for a PMCW automotive radar using the suppression method, a multi-channel transceiver using the suppression circuit, and a multi-transmit / multi-receive radar system using the multi-channel transceiver.

[0006] This invention is achieved using the following technical solution: The first aspect of this invention provides a method for suppressing transmitter leakage signals in a multi-channel transceiver, comprising:

[0007] Activate each of the transmitter's multiple transmission channels one by one;

[0008] Because of any number i The new time-varying transmission channel is opened t Changing transmitted signal R i ( t This signal carries the leakage signal from the transmitting channel, which, after transimpedance amplification and analog-to-digital conversion, forms a digital receiving sequence with the transmission leakage component. S i ( n ), n Indicates to R i ( t The nth sampling time is used for sampling.

[0009] Based on the known transmission baseband sequence P i ( n )and S i ( n Design digital compensation sequence C i ( n ):make C i ( n )= A i ( k i )• P i ( n In the formula, A i ( k i )= A i ( k i -1)+ μ •f ( S i ( n )• P i ( n )), A i ( k i ), A i ( k i -1) are respectively the construction C i ( n The first time k i sequence k i The iteration weight for -1 iterations. A i (0) represents the initial iteration weights. μ This is the iteration step size; f (•) is a symbolic function or an equivalent mapping function; determine S i ( n If the sampling amplitude of is less than the minimum valid number of bits for the analog-to-digital conversion, then output the current C. i ( n ), and open the next transmission channel; otherwise, return to the previous step for C. i ( n Proceed to the next iteration;

[0010] Will C i ( n The analog compensation signal is generated after digital-to-analog conversion and transconductance amplification. C i ( t Negative feedback to R i ( t ), S i ( n This results in a digital receive sequence that cancels out transmission leakage components. At this time, the transmitted signal received by each receiving channel of the receiver R ( t and the corresponding digital receiving sequence S ( n They are respectively: , .

[0011] As a further improvement to the above scheme, the initial iteration weights are set to 0 by default.

[0012] As a further improvement to the above scheme, the transimpedance amplification is achieved through a transimpedance amplifier.

[0013] As a further improvement to the above scheme, the analog-to-digital conversion is implemented through an analog-to-digital converter (ADC).

[0014] As a further improvement to the above scheme, the digital-to-analog conversion is achieved through a digital-to-analog converter (DAC).

[0015] As a further improvement to the above scheme, the transconductance amplification is achieved through a transconductance amplifier.

[0016] As a further improvement to the above scheme, the negative feedback is implemented using a subtractor.

[0017] A second aspect of the present invention also provides a radio wave ranging or speed measurement method for a PMCW automotive radar, which samples the transmitter leakage signal suppression method of any of the above-mentioned multi-channel transceivers, suppresses the transmitter leakage signal carried in the radio waves received by the receiver, and uses the suppressed radio waves for radio wave ranging or speed measurement.

[0018] A third aspect of the present invention also provides a transmitter leakage signal suppression circuit for a multi-channel transceiver, comprising:

[0019] An adaptive suppression processor is used to sequentially activate each of the transmitter's multiple transmission channels and, based on the known transmission baseband sequence... P i ( n ) and digital receiving sequence S i ( n Design digital compensation sequence C i ( n );

[0020] in, S i ( t ) is: because any number of i The new time-varying transmission channel is opened t Changing transmitted signal R i ( t This signal carries the leakage signal from the transmitting channel, which, after transimpedance amplification and analog-to-digital conversion, forms a digital receiving sequence with the transmission leakage component. n Indicates to R i ( t The nth sampling time is used for sampling.

[0021] C i (n ) is: Let C i ( n )= A i ( k i )• P i ( n In the formula, A i ( k i )= A i ( k i -1)+ μ • f ( S i ( n )• P i ( n )), A i ( k i ), A i ( k i -1) are respectively the construction C i ( n The first time k i sequence k i The iteration weight for -1 iterations. A i (0) represents the corresponding initial iteration weight. μ This is the iteration step size; f (•) is a symbolic function or an equivalent mapping function; determine S i ( n If the sampling amplitude of is less than the minimum valid number of bits for the analog-to-digital conversion, then output the current C. i ( n ), and open the next transmission channel; otherwise, return to the previous step for C. i ( n Proceed to the next iteration;

[0022] Digital-to-analog converter, used for digital-to-analog conversion C i ( n ) Generate analog compensation signal C i ( t );

[0023] Transconductance amplifier, used for transconductance amplification C i ( t );

[0024] A subtractor is used to amplify the transconductance. C i ( t Negative feedback to R i (t), S i ( n This results in a digital receive sequence that cancels out transmission leakage components. At this time, the transmitted signal received by each receiving channel of the receiver R ( t and the corresponding digital receiving sequence S ( n They are respectively: , .

[0025] As a further improvement to the above scheme, the initial iteration weights are set to 0 by default.

[0026] As a further improvement to the above scheme, the digital-to-analog converter is a digital-to-analog converter with 6 bits of binary code + 7 bits of hot code.

[0027] As a further improvement to the above scheme, the transconductance amplifier is a transconductance amplifier with a low-pass filter.

[0028] A fourth aspect of the present invention also provides a multi-channel transceiver, comprising a multi-channel transmitter and a multi-channel receiver, wherein each receiving channel of the receiver includes:

[0029] Transimpedance amplifiers are used to process time-varying signals coupled with leakage. t Changing transmitted signal R i ( t Transimpedance amplification is performed.

[0030] Analog-to-digital converter, used for transimpedance amplification R i ( t Perform analog-to-digital conversion and form a transmission sequence with transmission leakage components. S i ( n ); n Indicates to R i ( t The sampling was performed on the first n Each sampling time;

[0031] The transmitter leakage signal suppression circuit of the above-mentioned multi-channel transceiver suppresses the transmitter leakage signal at the output of the analog-to-digital converter and then negatively feeds it back to the input of the transimpedance amplifier.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) This invention opens the multiple transmission channels of the transmitter one by one, rather than opening some or all of them simultaneously. It also designs a specific adaptive suppression method in conjunction with the transimpedance amplification and analog-to-digital conversion of each receiving channel of the receiver (adaptive leakage modeling and cancellation mechanism based on known transmission baseband sequence: This invention makes full use of the known and reproducible characteristics of the transmission baseband sequence in the radar. By performing correlation processing between the received signal and the transmission baseband sequence, it achieves adaptive estimation of the transmission leakage component and generates a corresponding compensation signal for cancellation). This enables the transmitter leakage signal to be iteratively canceled when each transmission channel is opened. Thus, it can effectively suppress multiple transmission leakage signals while keeping the performance of the receiving front end basically unaffected, and ultimately improve the receiving sensitivity and overall performance of the radar system in multi-channel working mode.

[0034] (2) Although the multi-channel transceiver of the present invention requires the transmitter's multiple transmission channels to be turned on one by one before application, and corresponding adaptive suppression is performed each time a transmission channel is turned on, compared with the existing transmission leakage suppression scheme based on correlation cancellation (although the structure is simple and the working mechanism is clear, it is usually only applicable to single-path transmission signals and is difficult to extend to multi-transmitter scenarios), the transmitter of the present invention can eventually turn on all multiple transmission channels, and therefore can be applied to multi-path transmission signals.

[0035] Compared to existing multi-channel transmit leakage suppression schemes (which, while capable of handling multiple transmit signals simultaneously, often require complex suppression loops and additional signal paths in the RF front-end, potentially negatively impacting impedance matching, noise figure, and system signal-to-noise ratio at the receiver front-end, and significantly increasing chip area and power consumption), this invention employs the same adaptive suppression method for each iteration. It eliminates the need for complex suppression loops and additional signal paths between iterations. Furthermore, although the adaptive suppression method remains consistent, the iterative mechanism ensures that the impedance matching, noise figure, and system signal-to-noise ratio at the receiver front-end are not negatively affected, thus avoiding a significant increase in chip area and power consumption. In other words, this invention achieves a balance between suppression performance and system cost by avoiding complex multi-channel RF replication, adjustable front-end networks, and large-scale analog circuits. While achieving effective transmit leakage suppression, this invention significantly reduces system complexity, chip area, and power consumption, making it suitable for engineering implementation in highly integrated radar transceivers. This invention's overall technical concept ensures multi-channel suppression capabilities while reducing additional hardware costs. Therefore, unlike existing multi-channel suppression schemes that introduce a cancellation loop into the RF front-end, this invention achieves transmit leakage suppression in the baseband or equivalent low-frequency domain through a closed-loop structure of "ADC—adaptive processing—DAC—transconductance feedback" (the adaptive closed-loop suppression structure is implemented outside the RF front-end), thereby avoiding damage to the impedance matching and noise figure of the receiving front-end. The specific implementation location of the leakage suppression loop and its feedback injection method in this invention decouple the suppression effect from the RF performance of the front-end.

[0036] (3) The adaptive suppression mechanism of the present invention does not rely on the assumption of a single transmission channel, but can generate corresponding compensation signals for the baseband sequences of multiple transmission channels to suppress leakage from multiple transmissions, and is suitable for multiple-transmission and multiple-receiver radar systems. Therefore, the present invention has natural scalability for multiple transmission channels without the need to set up an independent radio frequency suppression path for the transmission signal of each transmission channel. Attached Figure Description

[0037] Figure 1 This is a flowchart of a transmitter leakage signal suppression method for a multi-transmitter, multi-receiver radar system provided in Embodiment 1 of the present invention.

[0038] Figure 2 To achieve Figure 2 A schematic diagram of the transmitter leakage signal suppression circuit of the Chinese method.

[0039] Figure 3 The present invention provides a transmitter leakage signal suppression circuit with two transmission channels Tx1 and Tx2 as an example, and its multi-channel transmitter leakage signal suppression flowchart is shown in Embodiment 2 of the present invention.

[0040] Figure 4 for Figure 3 The timing diagram used.

[0041] Figure 5 for Figure 3 A circuit diagram of a digital-to-analog converter for a transmitter leakage signal suppression circuit.

[0042] Figure 6 for Figure 3 A circuit diagram of the transconductance amplifier in the transmitter leakage signal suppression circuit. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Example 1

[0045] Embodiment 1 of this invention introduces a transmitter leakage signal suppression method for a multi-channel transceiver, used to suppress transmitter leakage signals coupled from the transmitting end (transmitter) to the receiving end (receiver). Leakage signals from all transmitting channels of the transmitter can be referred to as transmitter leakage signals. A corresponding transmitter leakage signal suppression circuit for a multi-channel transceiver can be designed to implement the transmitter leakage signal suppression method of this invention. A multi-channel transceiver includes a multi-channel transmitter and a multi-channel receiver. The transmitter leakage signal suppression method suppresses the transmitter leakage signals coupled to each receiving channel of the receiver. Each receiving channel of the receiver generally includes a transimpedance amplifier, an analog-to-digital converter, and the transmitter leakage signal suppression circuit.

[0046] Multi-channel transceivers can be applied to multiple-transmitter, multiple-receiver radar systems to transmit and receive radio waves while suppressing transmission leakage signals coupled from the transmitter to the receiver. Multiple-transmitter, multiple-receiver radar systems can be radar or communication transceiver systems, such as PMCW multiple-transmitter, multiple-receiver radars, specifically PMCW automotive radars, which can be used for radio wave ranging or speed measurement. The radio wave ranging or speed measurement method of this PMCW automotive radar can utilize the transmitter leakage signal suppression method of this invention to suppress the transmitter leakage signal carried in the radio waves received by the receiver. The suppressed radio waves can significantly improve the accuracy of radio wave ranging or speed measurement. Because the transmitter leakage signal carried in the radio waves is suppressed, the dynamic range of the PMCW automotive radar's radio ranging or speed measurement can also be improved.

[0047] Please see Figure 1The transmitter leakage signal suppression method for a multi-channel transceiver of the present invention includes the following steps:

[0048] Activate each of the transmitter's multiple transmission channels one by one;

[0049] Because of any number i The new time-varying transmission channel is opened t Changing transmitted signal R i ( t This signal carries the leakage signal from the transmitting channel, which, after transimpedance amplification and analog-to-digital conversion, forms a digital receiving sequence with the transmission leakage component. S i ( n ), n Indicates to R i ( t The nth sampling time is used for sampling.

[0050] Based on the known transmission baseband sequence P i ( n )and S i ( n Design digital compensation sequence C i ( n ):make C i ( n )= A i ( k i )• P i ( n In the formula, A i ( k i )= A i ( k i -1)+ μ • f ( S i ( n )• P i ( n )), A i ( k i ), A i ( k i -1) are respectively the constructionC i ( n The first time k i sequence k i The iteration weight for -1 iterations. A i (0) represents the corresponding initial iteration weight. μ This is the iteration step size; f (•) is a symbolic function or an equivalent mapping function; determine S i ( n If the sampling amplitude of is less than the minimum valid number of bits for the analog-to-digital conversion, then output the current C. i ( n ), and open the next transmission channel; otherwise, return to the previous step for C. i ( n Proceed to the next iteration;

[0051] Will C i ( n The analog compensation signal is generated after digital-to-analog conversion and transconductance amplification. C i ( t Negative feedback to R i ( t ), S i ( n This results in a digital receive sequence that cancels out transmission leakage components. At this time, the transmitted signal received by each receiving channel of the receiver R ( t and the corresponding digital receiving sequence S ( n They are respectively: , .

[0052] In other words, initially, only one transmit channel of the transmitter is activated, and each receive channel of the receiver is only coupled to the leakage signal of that transmit channel and adaptively suppressed. Therefore, at this time, each receive channel receives a time-varying signal carrying only the leakage signal of one transmit channel. t Changing transmitted signal R 1( t After transimpedance amplification and analog-to-digital conversion, a digital receiver sequence with a transmit leakage component is formed. S 1( n ), n Take a positive integer. For the received digital sequence. S 1(n Sampling is performed based on the known transmit baseband sequence. P 1( n ) and digital receiving sequence S 1( n Design digital compensation sequence C 1( n The baseband sequence for each transmission channel can be the same or different. The digital compensation sequence... C 1( n The analog compensation signal is generated after digital-to-analog conversion and transconductance amplification. C 1( t ), negative feedback to the transmitted signal R 1( t To cancel out the transmitter leakage signal coupled to the receiver, the digital received sequence can be... S 1( n The digital receive sequence is transformed into a transmit leakage component cancellation sequence. . t It is a time variable.

[0053] Digital Compensation Sequence C i ( n The design method is described below.

[0054] First of all, let C 1( n )= A 1(1)• P 1( n In the formula, A 1(1) is used to open and construct the first transmission channel. C 1( t The iteration weight of the first iteration when ) A 1(1)= A 1(0)+ μ • f ( S 1( n )• P 1( n )), A 1(0) is C 1( n The initial iteration weights (usually 0) correspond to the ). μ This is the iteration step size; f (•) represents a symbolic function or an equivalent mapping function.

[0055] Secondly, judgment S 1( n If the sampling amplitude of C1 is less than the minimum valid sampling bits of the analog-to-digital converter, then output the current C1( n(That is to say, the current C1( n (This is the digital compensation sequence required when the first transmission channel is activated), and then activate the next transmission channel; otherwise, return to the previous step and apply C1 ( n Then proceed to the next iteration. Therefore, S 1( n If the sampling amplitude of C1 is less than the minimum valid sampling bit of the analog-to-digital converter, then the leakage of the transmission channel can be considered completely suppressed, and C1 can be determined. n The specific digital compensation sequence is then established, and the next launch channel is activated.

[0056] Once the next transmit channel is activated, each receive channel of the receiver will be coupled to the leakage signals from both transmit channels and adaptively suppressed. Therefore, each receive channel at this time receives a transmit signal carrying the leakage signals from both transmit channels, but the leakage signal from one of the transmit channels has already been suppressed. The transmit signal received by each receive channel at this time... R ( t )yes: R 1( t )-C1(t)+ R 2( t ). R 1( t The digital received sequence formed after transimpedance amplification and analog-to-digital conversion of )-C1(t) The leakage signal from that transmission channel has been canceled out. There is no transmission leakage component. However, there is an additional transmission signal due to the opening of the second transmission path. R 2( t After transimpedance amplification and analog-to-digital conversion, a digital receiver sequence with transmit leakage components is formed. S 2( n Therefore, the current digital reception sequence S ( n )yes: + S 2( n ). For digital received sequences S ( n Sampling was performed, but because S 1( n The sampling amplitude is less than the minimum valid bits of the analog-to-digital converter, therefore the sampled signal is essentially a digital received sequence. S 2( n Based on the known transmission baseband sequence P 2( n ) and digital receiving sequence S 2( n Design digital compensation sequenceC 2( n ).

[0057] C 2( n ) design method and C 1( n The design is the same as that of the previous one, as described below.

[0058] First of all, let C 2( n )= A 2(1)• P 2( n In the formula, A 2(1) is the first transmission channel that is opened and constructed. C 2( n The iteration weight of the first iteration when ) A 2(1)= A 2(0)+ μ • f ( S 2( n )• P 2( n )), A 2(0) is C 2( n The initial iteration weights (usually 0) correspond to the ). μ This is the iteration step size; f (•) represents a symbolic function or an equivalent mapping function.

[0059] Secondly, judgment S 2( n If the sampling amplitude of C2 is less than the minimum valid sampling bits of the analog-to-digital converter, then output the current C2( n ), and open the next transmission channel; otherwise, return to the previous step for C2 ( n Then proceed to the next iteration. Therefore, S 2( n If the sampling amplitude of C2 is less than the minimum valid sampling bit of the analog-to-digital converter, then the leakage of the transmission channel can be considered completely suppressed, and C2 can be determined. n The specific value of ) is determined, and the next transmission channel is opened.

[0060] This process continues until all transmission channels of the transmitter are activated. Each activation of a transmission channel requires a corresponding design. C i ( n In the design C i ( n When ), the number of iterations k iIt is possible that they will differ. The transmitted signal received by each receive channel of the receiver... R ( t and the corresponding digital receiving sequence formed therefrom. S ( t They can be summarized as follows: , .

[0061] Compared with the prior art, the present invention has at least the following beneficial effects:

[0062] (1) It can effectively suppress multi-channel emission leakage signals.

[0063] This invention is based on known transmission baseband sequences P i ( n ), the digital received sequence received by the receiver S i ( n Adaptive modeling and cancellation can effectively suppress leakage signals from multiple transmitters when multiple transmitter channels are operating simultaneously, overcoming the technical limitations of existing single-channel leakage suppression schemes that are difficult to extend to multiple transmit and receive systems.

[0064] (2) It can avoid adverse effects on the performance of the radio frequency front end.

[0065] The leakage suppression of this invention is mainly achieved through adaptive processing and feedback injection in the baseband or equivalent low-frequency domain. It does not require the introduction of complex suppression circuits or additional RF devices in the RF front end, thereby avoiding damage to the impedance matching, noise figure and linearity of the receiving front end, which is beneficial to maintaining the intrinsic performance of the receiver.

[0066] (3) The suppression loop has a simple structure and low system implementation complexity.

[0067] This invention employs a closed-loop suppression structure consisting of analog-to-digital conversion, adaptive processing (adaptive suppression mode), digital-to-analog conversion, and transconductance feedback. Each functional module has a clear division of labor and a clear interface, avoiding multi-channel RF replication and complex front-end calibration. The overall circuit structure is relatively simple and easy to integrate and implement in engineering.

[0068] (4) It helps to reduce chip area and power consumption.

[0069] Since this invention does not require additional multi-channel RF transmission replicas and complex front-end suppression networks, it can significantly reduce circuit resource usage, chip area and power consumption, making it particularly suitable for highly integrated, low-power multi-channel radar transceiver systems.

[0070] (5) Improve the dynamic range and signal-to-noise ratio of the receiving link.

[0071] By effectively suppressing the transmitted leakage signal, this invention can reduce the risk of receiver front-end saturation and the impact of quantization noise, thereby improving the effective dynamic range and signal-to-noise ratio of the receiver link and thus improving the detection performance of weak targets.

[0072] Please see Figure 2 This is a circuit diagram illustrating the implementation of the transmitter leakage signal suppression method of the present invention. Each receiving channel of the receiver generally includes a transimpedance amplifier (TIA) and an analog-to-digital converter (ADC) connected in series. To apply the transmitter leakage signal suppression method of the present invention, a transmitter leakage signal suppression circuit is designed to sample the output of the ADC, process the sampled data, and then negatively feed it back to the input of the transimpedance amplifier (TIA). The specific implementation location and negative feedback injection method of the transmitter leakage signal suppression circuit of the present invention decouple the suppression effect from the front-end RF performance, thereby achieving the purpose of the transmitter leakage signal suppression method. Therefore, in this embodiment, the multi-channel transceiver of the present invention includes a transmitter leakage signal suppression circuit in each receiving channel, in addition to the transimpedance amplifier and the ADC connected in series. The transmitter leakage signal suppression circuit includes an adaptive suppression processor (LMS), a digital-to-analog converter (DAC), a transconductance amplifier (Gm), and a subtractor. The transimpedance amplifier, the ADC, the adaptive suppression processor (LMS), the DAC, the Gm, and the subtractor constitute a circuit loop.

[0073] The adaptive suppression processor samples the output of the LMS analog-to-digital converter (ADC) to remove the transmitted signal coupled with leakage signals. R i ( t After transimpedance amplification and analog-to-digital conversion, a transmission sequence with emission leakage components is formed. S i ( n ).based on S i ( n ) and transmit baseband sequence P i ( n Generate a digital compensation sequence for transmitter leakage signal cancellation. C i ( n The digital-to-analog converter (DAC) converts the digitally compensated sequence. C i ( n The digital-to-analog conversion is performed. The transconductance amplifier Gm converts the digitally compensated sequence from the digital-to-analog conversion. C i ( n Transconductance amplification is performed to ultimately form an analog compensated signal. C i ( tThe subtractor will pass the analog compensation sequence after digital-to-analog conversion and transconductance amplification. C i ( t Negative feedback to the transmitted signal R i (t) is used to cancel out the transmitter leakage signal coupled to the receiver.

[0074] The adaptive suppression processor LMS preferably employs the Least Mean Square (LMS) algorithm, which internally includes a weight update unit and a sequence generation unit. The adaptive suppression processor LMS is based on... A i ( k i -1)+μ•f( S i ( n )• P i ( n Update the weights. k i Indicates the number of iterations. When S i ( n )and P i ( n If the signs are the same (both greater than 0 or both less than 0), the estimated leakage magnitude weights are increased by one step; otherwise, they are decreased by one step. Based on the updated weights, the adaptive suppression processor LMS generates a digital compensation sequence for leakage compensation: C i ( n )= A i ( k i )• P i ( n ).

[0075] Example 2

[0076] Please combine Figure 3 and Figure 4Taking two transmission channels Tx1 and Tx2 as an example: Suppose Tx1 leaks into the ADC input of a PRBS signal of 100mVpp with reversed polarity (i.e., -100mVpp*P(n)). The ADC sampling output is compared with the pseudo-random sequence PRBS. The polarity of the code at the same time is different, so the polarity is reversed. Then it is determined whether the ADC sampling output is 0. At this time, it is not 0. Continue to determine whether the polarity of the ADC sampling output and the PRBS signal are the same. At this time, they are the same. Then A(k) increases by a step size u. The LMS algorithm outputs a C1(n) = A1(k1) × P1(1) to the DAC for digital-to-analog conversion, where t is time, which is equal to the period multiplied by the number of iterations. At this time, the DAC output is the PRBS modulation amplitude u with opposite polarity. After amplification, Gm draws a current of one step size unit, so that the ADC input is reduced to -99mVpp*P(n) (the step size can be adjusted until the minimum step size change is less than one LSB of the ADC sampling). Continue the loop until the ADC input decreases to -1mVpp*P(n) and 0mVpp*P(n).

[0077] The specific circuitry of the analog-to-digital converter (ADC) can be adjusted according to actual needs. In this embodiment, a 6-bit binary code (CoA) is used. <0> Coa <1> Coa <2> Coa <3> Coa <4> Coa <50> ) + 7-bit hot code (Fin <0> Fin <1> Fin <2> Fin <3> Fin <4> Fin <5> Fin <6> Digital-to-analog converters, such as Figure 5 The analog-to-digital converter (ADC) output signal shown is a digitally compensated signal. V out_dac The transimpedance amplifier (TIA) can also be adjusted according to actual needs. In this embodiment, a transconductance amplifier with a low-pass filter is used, such as... Figure 6 As shown, the transimpedance amplifier (TIA) is connected to the digital-to-analog converter (DAC) to convert the digital compensation signal. V out_dac Analog compensation signal converted to current form V out_Gm It is then injected into the subtractor so that it cancels out the transmit leakage component in the receive path in both amplitude and phase.

[0078] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for suppressing transmitter leakage signals in a multi-channel transceiver, characterized in that, It includes: Activate each of the transmitter's multiple transmission channels one by one; Because of any number i The new time-varying transmission channel is opened t Changing transmitted signal R i ( t It carries the leakage signal of the corresponding transmission channel, which, after transimpedance amplification and analog-to-digital conversion, forms a digital receiving sequence with transmission leakage components. S i ( n ), n Indicates to R i ( t The nth sampling time is used for sampling. Based on the known transmission baseband sequence P i ( n )and S i ( n Design digital compensation sequence C i ( n ):make C i ( n )= A i ( k i )• P i ( n In the formula, A i ( k i )= A i ( k i -1)+ μ • f ( S i ( n )• P i ( n )), A i ( k i ), A i ( k i -1) are respectively the construction C i ( n The first time k i sequence k i The iteration weight for -1 iterations. A i (0) represents the initial iteration weights. μ This is the iteration step size; f (•) is a symbolic function or an equivalent mapping function; determine S i ( n If the sampling amplitude of is less than the minimum valid number of bits for the analog-to-digital conversion, then output the current C. i ( n ), and open the next transmission channel; otherwise, return to the previous step for C. i ( n Proceed to the next iteration; Will C i ( n The analog compensation signal is generated after digital-to-analog conversion and transconductance amplification. C i ( t Negative feedback to R i ( t ), S i ( n This results in a digital receive sequence that cancels out transmission leakage components. ; At this time, the transmitted signal received by each receiving channel of the receiver R ( t and the corresponding digital receiving sequence S ( n They are respectively: , .

2. The transmitter leakage signal suppression method for a multi-channel transceiver according to claim 1, characterized in that, The initial iteration weights are set to 0 by default.

3. The transmitter leakage signal suppression method for a multi-channel transceiver according to claim 1, characterized in that, The transimpedance amplification is achieved through a transimpedance amplifier; And / or, the analog-to-digital conversion is achieved through an analog-to-digital converter (ADC).

4. The transmitter leakage signal suppression method for a multi-channel transceiver according to claim 1, characterized in that, The digital-to-analog conversion is achieved through a digital-to-analog converter (DAC). And / or, the transconductance amplification is achieved through a transconductance amplifier; And / or, the negative feedback is implemented using a subtractor.

5. A radio wave ranging or speed measurement method for a PMCW automotive radar, characterized in that, The sampling method described in any one of claims 1 to 4 is a transmitter leakage signal suppression method for a multi-channel transceiver, which suppresses the transmitter leakage signal carried in the radio waves received by the receiver, and the suppressed radio waves are used for ranging or speed measurement of radio waves.

6. A transmitter leakage signal suppression circuit for a multi-channel transceiver, characterized in that, It includes: An adaptive suppression processor is used to sequentially activate each of the transmitter's multiple transmission channels and, based on the known transmission baseband sequence... P i ( n ) and digital receiving sequence S i ( n Design digital compensation sequence C i ( n ); in, S i ( t ) is: because any number of i The new time-varying transmission channel is opened t Changing transmitted signal R i ( t It carries the leakage signal of the corresponding transmission channel, which, after transimpedance amplification and analog-to-digital conversion, forms a digital receiving sequence with transmission leakage components. n Indicates to R i ( t The nth sampling time is used for sampling. C i ( n ) is: Let C i ( n )= A i ( k i )• P i ( n In the formula, A i ( k i )= A i ( k i -1)+ μ • f ( S i ( n )• P i ( n )), A i ( k i ), A i ( k i -1) are respectively the construction C i ( n The first time k i sequence k i The iteration weight for -1 iterations. A i (0) represents the corresponding initial iteration weight. μ This is the iteration step size; f (•) is a symbolic function or an equivalent mapping function; determine S i ( n If the sampling amplitude of is less than the minimum valid number of bits for the analog-to-digital conversion, then output the current C. i ( n ), and open the next transmission channel; otherwise, return to the previous step for C. i ( n Proceed to the next iteration; Digital-to-analog converter, used for digital-to-analog conversion C i ( n ) Generate analog compensation signal C i ( t ); Transconductance amplifier, used for transconductance amplification C i ( t ), A subtractor is used to amplify the transconductance. C i ( t Negative feedback to R i (t), S i ( n This results in a digital receive sequence that cancels out transmission leakage components. At this time, the transmitted signal received by each receiving channel of the receiver R ( t and the corresponding digital receiving sequence S ( n They are respectively: , .

7. The transmitter leakage signal suppression circuit of the multi-channel transceiver according to claim 6, characterized in that, The initial iteration weights are set to 0 by default.

8. The transmitter leakage signal suppression circuit of the multi-channel transceiver according to claim 6, characterized in that, The digital-to-analog converter is a digital-to-analog converter with 6 bits of binary code + 7 bits of hot code.

9. The transmitter leakage signal suppression circuit of the multi-channel transceiver according to claim 6, characterized in that, The transconductance amplifier is a transconductance amplifier with a low-pass filter.

10. A multi-channel transceiver, comprising a multi-channel transmitter and a multi-channel receiver, wherein each receive channel of the receiver includes: Transimpedance amplifiers are used to process time-varying signals coupled with leakage. t The changing transmitted signal R i (t) performs transimpedance amplification; Analog-to-digital converter, used to amplify the R signal after transimpedance amplification. i (t) Perform analog-to-digital conversion and form a transmission sequence S with transmission leakage component. i (n); n Indicates to R i ( t The nth sampling time is used for sampling. Its characteristic is that it further includes: The transmitter leakage signal suppression circuit of the multi-channel transceiver as described in any one of claims 6 to 9, after suppressing the transmitter leakage signal at the output of the analog-to-digital converter, is negatively fed back to the input of the transimpedance amplifier.

Images