WO2023103272A1 - 一种射频干扰抵消器及方法 - Google Patents

一种射频干扰抵消器及方法 Download PDF

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WO2023103272A1
WO2023103272A1 PCT/CN2022/091290 CN2022091290W WO2023103272A1 WO 2023103272 A1 WO2023103272 A1 WO 2023103272A1 CN 2022091290 W CN2022091290 W CN 2022091290W WO 2023103272 A1 WO2023103272 A1 WO 2023103272A1
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digital
radio frequency
signal
analog
power amplifier
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PCT/CN2022/091290
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English (en)
French (fr)
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陈顺阳
张琦
陈加锐
黄晓国
杨会宇
楼红斌
朱梦磊
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中国电子科技集团公司第三十六研究所
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Publication of WO2023103272A1 publication Critical patent/WO2023103272A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
    • H04B1/1027—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal
    • H04B1/1036—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters

Definitions

  • the invention relates to the technical field of signal processing, in particular to a radio frequency interference canceller and method.
  • Multi-functional mission systems such as radar, communication, and electronic warfare have phenomena such as frequency overlap, space congestion, and huge contrast between strong and weak signals on the same mission platform.
  • the transmitter When the transmitter is working, such as radar, communication, electronic interference, etc., it will form strong co-site interference to receiving equipment in the same frequency band, such as electronic reconnaissance, signal intelligence, communication reception, etc., causing serious electromagnetic compatibility problems and greatly reducing the mission. efficacy.
  • the role of the radio frequency interference canceller is to use the coherence of the co-site interference signal to reconstruct the interference signal through circuits and algorithms, and actively cancel the interference signal at the receiver side.
  • the wider the interference signal bandwidth the greater the delay leakage of the interference channel and the greater the difficulty of offsetting.
  • the so-called delay leakage refers to the delay difference introduced by the actual interference signal through different transmission paths, including scattering and multipath.
  • TBP Time-Bandwidth Product
  • the broadband radio frequency interference cancellation mainly adopts the tapped delay line (TDL, Tapped Delay Line) scheme.
  • the basic principle is that the basic unit of radio frequency interference reconstruction (also called tapped ), and adjust the delay, amplitude, and phase of each tap to reconstruct the co-site interference channel.
  • the reconstructed channel matches the interference channel precisely, the broadband radio frequency interference signal can be completely canceled.
  • the TDL scheme has the following problems:
  • TDL uses analog adjustment devices, such as delay lines, attenuators, phase shifters, etc., and the accuracy is not high;
  • TDL taps are limited, generally 8 taps, and the adjustment accuracy is limited. It is difficult to match complex channel responses with high precision, and cannot adjust for scenarios with large TBP values. This is because when the product of the total delay leakage from the transmitter interference signal to the receiver and the signal bandwidth is greater than 1, high requirements are placed on the accuracy and number of taps of the reconstruction filter, which cannot be offset by the existing TDL scheme.
  • TDL will introduce high insertion loss as the number of taps increases, thus adding active amplification will introduce new noise.
  • the main purpose of the present invention is to provide a radio frequency interference canceller and method to solve the problem of the existing TDL scheme in large The problem that the cancellation signal cannot be accurately reconstructed in the time-bandwidth product application scenario.
  • a radio frequency interference canceller including: a controller, a first power amplifier, a digital filter, a second power amplifier, a first analog-to-digital converter, a second analog-to-digital converter, a first digital-to-analog converter, a second digital-to-analog converter, a splitter and a combiner;
  • the output end of the controller is connected to the input end of the first digital-to-analog converter, and the output end of the first digital-to-analog converter is connected to the input end of the first power amplifier;
  • the second analog-to-digital converter, the digital filter, the second digital-to-analog converter, and the second power amplifier are connected in sequence, the output end of the second power amplifier is connected to the coupling end of the combiner, and the input end of the combiner can be disconnected Connect the receiving antenna, the output end of the combiner is connected to the input end of the first analog-to-digital converter and the low-noise amplifier on the receiver side, and the output end of the first analog-to-digital converter is connected to the input end of the controller;
  • the input end of the splitter is connected to the transmitter power amplifier and the output end of the first power amplifier, the output end of the splitter is connected to the transmitting antenna, and the coupling end of the splitter is connected to the input end of the second analog-to-digital converter. ;
  • the digital filter is also connected to the control terminal of the controller;
  • the controller calculates the reconstruction coefficient of the digital filter, loads the reconstruction coefficient into the digital filter, adjusts the cancellation signal through the digital filter loaded with the reconstruction coefficient, and performs radio frequency interference cancellation on the interference signal in the radio frequency receiving signal .
  • a radio frequency interference cancellation method including:
  • the radio frequency interference canceller controls the radio frequency interference canceller sequentially in the test mode of the external interference channel and the test mode of the cancellation channel, and calculate the first impulse response and the second impulse response of the channel under the two test modes; wherein, the radio frequency interference canceller is the above-mentioned radio frequency interference canceller;
  • the radio frequency interference canceller is controlled to switch to the normal working mode, and the digital filter in the reconstruction channel performs signal processing on the radio frequency coupling signal to obtain a cancellation signal, and uses the cancellation signal to cancel the radio frequency interference of the interference signal in the radio frequency receiving signal.
  • the radio frequency interference canceller provided by the embodiment of the present invention establishes a reconstructed channel through a splitter, two analog-to-digital converters, two digital-to-analog converters, a digital filter, two power amplifiers, and a combiner.
  • the coefficients of the digital filter are obtained by the controller based on digital signal processing, and the cancellation signal is conditioned by the digital filter in the digital domain, that is, the radio frequency interference canceller of this embodiment can generate an accurate digital filter in the digital domain.
  • the digital filter adjusts the high-precision cancellation signal in the digital domain, and cancels the radio frequency interference signal in real time.
  • the reconstruction method and precision of the digital filter determine the cancellation precision. Since the processing accuracy (digital bit width) and delay depth (tap number) of the digital domain are much higher than the TDL method of the analog domain, it has wide offset bandwidth, strong environmental adaptability (including scattering, multipath and other environments), interference suppression It has the characteristics of high ratio, small size, and good assembly performance, and is suitable for various waveforms such as fixed frequency, frequency hopping, and pulse. Therefore, through the radio frequency interference canceller of this embodiment, the electromagnetic compatibility problem introduced by the co-site interference of the multi-functional mission system can be solved, especially the difficult problem of co-site interference channel offsetting in the actual large time-bandwidth product scenario is solved, and the interference resistance is improved. The cancellation effect of the signal.
  • this embodiment adjusts the radio frequency coupling signal by reconstructing the channel, and does not directly adapt to the adjustment of the broadband signal. has strong robustness.
  • Fig. 1 shows a structural block diagram of a radio frequency interference canceller according to an embodiment of the present invention
  • FIG. 2 shows a schematic circuit diagram of a radio frequency interference canceller working in a test mode of an external interference channel according to an embodiment of the present invention
  • FIG. 3 shows a schematic circuit diagram of a radio frequency interference canceller working in a test mode of an internal reconfigured channel according to an embodiment of the present invention
  • FIG. 4 shows a schematic circuit diagram of a radio frequency interference canceller working in a normal working mode according to an embodiment of the present invention
  • FIG. 5 shows a schematic diagram of a parallel FIR structure of a digital filter according to an embodiment of the present invention
  • Fig. 6 shows the frequency response measured figure (input terminal increases 30dB protection attenuator in the test) that the network analyzer before the interference cancellation of the radio frequency interference canceller according to an embodiment of the present invention shows;
  • Fig. 7 shows the frequency response measured figure (input terminal increases 30dB protection attenuator in the test) shown by the network analyzer after the interference cancellation of the radio frequency interference canceller according to one embodiment of the present invention
  • Fig. 8 shows a flowchart of a radio frequency interference cancellation method according to an embodiment of the present invention.
  • the transmitter of the communication station includes a transmitting digital processor, a digital-to-analog converter, an up-converter, a power amplifier, and a transmitting antenna
  • the receiver includes a receiving antenna, a radio frequency interference canceller, a low noise amplifier (Low Noise Amplifier, LNA for short), a downlink Frequency converters, analog-to-digital converters, digital interference cancellation devices, and receiving digital processors.
  • LNA Low Noise Amplifier
  • the RF reception signal received by the receiver includes interference signals and useful signals.
  • the strength of the interference signal is much greater than that of the useful signal. Therefore, it is necessary to offset the interference signal in the RF reception signal, otherwise it will cause the low noise amplifier at the front end of the receiver, etc. Module blocking.
  • the radio frequency interference canceller takes the radio frequency signal amplified by the transmitter power amplifier as a reference signal, estimates the channel parameters from the local transmitting antenna to the receiving antenna, such as amplitude and phase, and adjusts the reference signal so that It is as close as possible to the interference signal component in the received signal, so as to cancel the interference signal received by the receiving antenna in the analog domain.
  • the basic technical idea of the embodiment of the present invention is to design a radio frequency reconstruction and cancellation circuit, conduct an online test on the impulse response of the external interference channel and the impulse response of the internal reconstruction channel, and based on the test results Generate high-precision digital filter coefficients in the digital domain, adjust the internal reconstruction channel based on the digital filter coefficients, and use the adjusted reconstruction channel to cancel the interference signal in real time.
  • FIG. 1 shows a structural block diagram of a radio frequency interference canceller according to an embodiment of the present invention, as shown in Figure 1, the radio frequency interference canceller of this embodiment includes: a controller, a first power amplifier, a digital filter, The second power amplifier, the first analog-to-digital converter (Analog to Digital Converter, referred to as ADC), the second analog-to-digital converter (Digital to Analog Converter, referred to as DAC), the first digital-to-analog converter, the second digital-to-analog converter Converters, splitters and combiners.
  • ADC Analog to Digital Converter
  • DAC Digital to Analog Converter
  • the output end of the controller is connected to the input end of the first digital-to-analog converter, and the output end of the first digital-to-analog converter is connected to the input end of the first power amplifier;
  • the second analog-to-digital converter, the digital filter, the second digital-to-analog converter, and the second power amplifier are connected in sequence, the output end of the second power amplifier is connected to the coupling end of the combiner, and the input end of the combiner can be disconnected Connect the receiving antenna, the output end of the combiner is connected with the input end of the first analog-to-digital converter and the low-noise amplifier gate of the receiver side, and the output end of the first analog-digital converter is connected with the input end of the controller;
  • the input end of the splitter is connected to the output end of the transmitter power amplifier and the first power amplifier, the output end of the splitter is connected to the transmitting antenna, and the coupling end of the splitter is connected to the input end of the second analog-to-digital converter;
  • the digital filter is also connected to the control terminal of the controller;
  • the controller calculates the reconstruction coefficient of the digital filter, loads the reconstruction coefficient into the digital filter, adjusts the cancellation signal through the digital filter loaded with the reconstruction coefficient, and performs radio frequency interference cancellation on the interference signal in the radio frequency receiving signal .
  • the splitter couples the radio frequency signal from the interference signal and inputs it to the reconstructed channel as a reference signal, and the combiner combines the adjusted radio frequency cancellation signal into the combiner, and the radio frequency The interference signal in the received signal is cancelled.
  • the first digital-to-analog converter is used to convert the test signal output by the controller into an analog signal, so that the first power amplifier performs power amplification on the analog signal;
  • the first analog-to-digital converter is used to convert the analog signal output by the combiner
  • the response signal is converted into a digital response signal, so that the controller can digitize the response signal;
  • the second analog-to-digital converter is used to convert the analog signal output by the splitter into a digital signal, so that the digital filter can process the digital signal Conditioning;
  • the second digital-to-analog converter is used to convert the digital signal conditioned by the digital filter into an analog signal, so that the second power amplifier can amplify the power of the analog signal.
  • the second power amplifier performs power amplification on
  • controller and digital filter are the core components of the radio frequency interference canceller.
  • the solid connection line in Figure 1 indicates that the two modules are in a direct electrical connection state
  • the first dotted connection line in Figure 1 indicates the strobe connection relationship
  • the second dotted connection line indicates that the two modules can be disconnected.
  • Open connection relationship for example, the first dotted connection line adopted by the output terminal side of the combiner indicates that the output terminal of the combiner is either connected with the low noise amplifier or connected with the first analog-to-digital converter; the input terminal of the combiner
  • the second type of dotted connection on the side indicates that the input of the combiner is either connected to the receiving antenna or not connected to the receiving antenna.
  • the radio frequency interference canceller shown in Figure 1 establishes a reconstruction channel through a splitter, two analog-to-digital converters, two digital-to-analog converters, a digital filter, two power amplifiers and a combiner, and reconstructs
  • the coefficients of the digital filter in the channel are obtained by the controller based on digital signal processing, and the cancellation signal is conditioned by the digital filter in the digital domain, that is, the radio frequency interference canceller of this embodiment can generate accurate digital filtering in the digital domain.
  • the high-precision cancellation signal is adjusted by the digital filter in the digital domain, and the radio frequency interference signal is canceled in real time.
  • the reconstruction method and precision of the digital filter determine the cancellation precision. Since the processing accuracy (digital bit width) and delay depth (tap number) of the digital domain are much higher than the TDL method of the analog domain, it has wide offset bandwidth, strong environmental adaptability (including scattering, multipath and other environments), interference suppression It has the characteristics of high ratio, small size, and good assembly performance, and is suitable for various waveforms such as fixed frequency, frequency hopping, and pulse.
  • the radio frequency interference canceller of this embodiment the electromagnetic compatibility problem introduced by the co-site interference of the multi-functional task system can be solved, especially the difficult problem of co-site interference channel offsetting in the actual large time-bandwidth product scenario is solved, and the interference signal is improved. offsetting effect.
  • the controller in this embodiment may be a system controller of a radio frequency interference canceller, which includes a central processing unit (Central Processing Unit, referred to as CPU), a random access memory (Random Access Memory, referred to as RAM), an input/output interface (Output/Input Interface, referred to as IO interface), etc., the CPU can generate training signal sources.
  • a radio frequency interference canceller which includes a central processing unit (Central Processing Unit, referred to as CPU), a random access memory (Random Access Memory, referred to as RAM), an input/output interface (Output/Input Interface, referred to as IO interface), etc.
  • the CPU can generate training signal sources.
  • the training signal source in this embodiment is preferably a monotone signal source.
  • the first digital-to-analog converter is used to convert the digital signal output by the training signal source in the controller into an analog signal, and the analog signal is amplified by the first power amplifier to form a high-power radio frequency signal, and the radio frequency signal is sent to the branch
  • the router performs splitting processing.
  • the second analog-to-digital converter is used to convert the radio frequency signal sent by the splitter into a digital signal, and the digital signal is conditioned by a reconstruction filter, and the conditioned digital signal is generated by the second digital-to-analog converter corresponding analog signals, and use the second power amplifier to amplify the power of the analog signals to obtain radio frequency signals.
  • the radio frequency signal is converted into a digital signal by the first analog-to-digital converter and sent to the controller.
  • the controller, the first analog-to-digital converter, the second analog-to-digital converter, the first digital-to-analog converter, the second digital-to-analog converter, and the digital filter form an application specific integrated circuit (Application Specific Integrated Circuit, Abbreviated as ASIC).
  • ASIC Application Specific Integrated Circuit
  • the core digital devices such as the controller, two analog-to-digital converters, two digital-to-analog converters, and digital filters are chip-processed, so that the radio frequency interference canceller has low delay, miniaturization, low cost and The feature of high performance not only facilitates the industrialization of the radio frequency interference canceller, but also improves the market competitiveness of the radio frequency interference canceller.
  • the radio frequency interference canceller in FIG. 1 further includes a first switch, a second switch and a third switch.
  • the fixed end of the first switch is connected to the input end of the splitter, and the movable end of the first switch can be selectively connected to the transmitter power amplifier or gated to be connected to the output end of the first power amplifier;
  • the fixed end of the second switch is connected to the output end of the combiner, and the movable end of the second switch can be optionally connected to the low noise amplifier or optionally connected to the input end of the first analog-to-digital converter;
  • the fixed end of the third switch is connected to the receiving antenna, and the movable end of the third switch can be disconnected and connected to the input end of the combiner.
  • the gate connection between the splitter and the transmitter power amplifier and the first power amplifier is realized by setting the first switch
  • the gate connection between the combiner and the low-noise amplifier and the first analog-to-digital converter is realized by setting the second switch
  • the disconnectable connection between the receiving antenna and the combiner is realized by setting the third switch.
  • the first switch and the second switch may be single-pole double-throw switches
  • the third switch may be a single-pole single-throw switch.
  • the radio frequency interference canceller in FIG. 1 further includes a first filter bank, a second filter bank and an attenuator.
  • the attenuator is a controllable attenuator, the attenuator is connected between the first filter bank and the second analog-to-digital converter, that is, the input end of the attenuator is connected to the output end of the first filter bank, and the output end of the attenuator Connect to the input of the second analog-to-digital converter.
  • the attenuator in this embodiment is used to adjust the operating point of the second power amplifier to keep it in the linear region.
  • the power of the power amplifier of the transmitter is very large. Take the radio station as an example, the power is 50-100W, or even greater. Considering engineering practicability, the power of the first power amplifier can be reduced to +20dBm, the requirements on active components can be reduced, and the volume of the radio frequency interference canceller can be reduced.
  • the attenuation value of the attenuator is 0 in the test mode, and the attenuation value of the attenuator in the normal working mode is -30dB, which not only ensures that the characteristics of the cancellation response loop remain unchanged, but also greatly reduces the power consumption of the radio frequency interference canceller.
  • the first filter bank is connected between the splitter and the attenuator, and the second filter bank is connected between the second power amplifier and the combiner.
  • the function of the first filter bank and the second filter bank is to perform anti-aliasing filtering on the radio frequency signal, and limit the non-linearity (mainly harmonics) of the power amplifier within the working bandwidth of the interference canceller.
  • the splitter is used to split the radio frequency signal
  • the combiner is used to combine the antenna signal and the radio frequency signal of the second filter bank.
  • the combiner and the splitter are couplers with small insertion loss.
  • the radio frequency interference canceller includes a radio frequency sampling unit M1 and a radio frequency reconstruction and cancellation unit M2, wherein the radio frequency sampling unit M1 is composed of a first coupler Couple1 and a radio frequency switch K1,
  • the radio frequency sampling unit M1 is mainly composed of passive components, which are placed between the transmitter power amplifier and the transmitting antenna in the form of small components.
  • the radio frequency reconstruction and cancellation unit M2 is mainly composed of an interference cancellation processor (ASIC) U1 and peripheral circuits of the interference cancellation processor U1, and is placed between the low noise amplifier and the receiving antenna in the form of a module.
  • ASIC interference cancellation processor
  • the interference cancellation processor U1 includes a controller Controller, a first digital-to-analog converter DAC1, a second digital-to-analog converter DAC2, a first analog-to-digital converter ADC1, a second analog-to-digital converter ADC2, and a digital filter PFIR.
  • the peripheral circuit includes a first power amplifier PA1, a second power amplifier PA2, a first filter bank BPFB1, a second filter bank BPFB2, an attenuator ATT, a second coupler Couple2, a radio frequency switch K2 and a radio frequency switch K3.
  • the radio frequency interference cancellation channel works in the 960-1250MHz band, that is, the instantaneous bandwidth is 290MHz
  • the filter bank BPFB is a band-pass of 960-1250MHz filter.
  • the coupling ratio of the coupler is 10dB
  • the maximum input interference power of the receiver is +20dBm
  • the power of the first power amplifier PA1 and the second power amplifier PA2 is 30dBm
  • the power of the transmitter is 100W
  • the maximum attenuation value of the attenuator AAT is 20dB.
  • connection relationship of each component refers to the description of the above-mentioned embodiment and with reference to Fig. 2-Fig.
  • the circuits in Fig. 2-Fig. 4 are simple, and the connection relationship between the controller of the controller and the radio frequency switches K1, K2, K3 and the attenuator ATT is not shown.
  • the interference cancellation processor U1 in this embodiment is used to complete the test of the external interference channel, the test of the internal reconstruction channel, the calculation of the reconstruction coefficient of the digital filter PFIR, and the real-time interference cancellation.
  • the three control processes are described in detail below.
  • the radio frequency interference canceller is controlled to work in the test mode of the external interference channel.
  • Both the RF switch K1 on the transmitter side and the RF switch K2 on the receiver side are placed in the test state, that is, the moving end of the RF switch K1 is connected to the output end of the first power amplifier PA1 (i.e., end 1 in Figure 2), and the RF The moving end of the switch K2 is connected to the input end of the first analog-to-digital converter ADC1 (that is, end 1 in Figure 2), and the RF switch K3 is closed, and the attenuator ATT is set to a straight-through state, that is, the attenuation value of the attenuator is set is 0dB, the filter coefficient of the digital filter PFIR is set to 0, that is, the reconstruction loop is disconnected.
  • the controller Controller In this working mode, the controller Controller generates a single-tone signal source, and controls the single-tone signal source to output the signal x(n) to the first digital-to-analog converter DAC1 at each set frequency point of the interference cancellation frequency band.
  • the single-tone signal source The audio signal source sends sweeping signals every 1MHz from 960MHz until 1250MHz.
  • the response data y 1 (n) sent by the first analog-to-digital converter ADC1 is received, and sample points are collected for the signals x(n) and y 1 (n) at each set frequency point.
  • each set frequency point can be collected at equal intervals in the interference cancellation frequency band.
  • 4096 sample points can be collected.
  • the number of sample points in each frequency point is set according to the requirements of accuracy and speed.
  • the radio frequency interference canceller is controlled to switch from the test mode of the external interference channel to the test mode of the reconstructed channel.
  • the switching method is to keep both the RF switch K1 on the transmitter side and the RF switch K2 on the receiver side in the test state, that is, the moving end of the RF switch K1 and the output end of the first power amplifier PA1 (that is, end 1 in Figure 3) Connect, the moving end of radio frequency switch K2 is connected with the input end (being 1 end in Fig.
  • the controller controls the single-tone signal source to output signal x(n) to the first digital-to-analog converter DAC1 at each set frequency point, where the output signal x(n) of the single-tone signal source is different from the external interference
  • the output signal x(n) in the test mode of the channel is the same, the response data y 2 (n) sent by the first analog-to-digital converter ADC1 is received, and the signals x(n) and y 2 ( n) Sample point collection is performed, and the sample point collection method is the same as the sample point collection method in the test mode of the external interference channel.
  • calculate the second frequency domain response H 2 of the second channel in this test mode is as follows:
  • ./ means the division of the corresponding frequency point, which is to divide the first frequency domain impulse response value corresponding to each set frequency point by the second frequency domain impulse response value of the corresponding frequency point, and the frequency value obtained is the opposite number (that is, a negative number) is the frequency domain reconstruction coefficient, which is subjected to inverse Fourier transform and length interception to obtain the time domain reconstruction coefficient of the digital filter PFIR.
  • the corresponding length truncation should be performed according to the number of taps of the digital filter. For example, if the digital filter has 64 taps, the truncation length is 64 taps.
  • time domain data x(n), y 1 (n), y 2 (n) can also be used to calculate the time domain reconstruction coefficient h r of the digital filter PFIR, but directly To obtain, the convolution needs to be solved in the time domain, and the computational complexity is relatively high.
  • the frequency-domain method converts the time-domain convolution calculation into the frequency-domain division calculation, and then uses the window function method to calculate the time-domain reconstruction coefficient.
  • the frequency-domain method has the advantage of simple calculation. In practical applications, those skilled in the art can flexibly choose the calculation method of the time domain reconstruction coefficient.
  • the first impulse response h 1 of the first channel in the test mode can be calculated from the test mode of the external interference channel.
  • the radio frequency interference canceller works in the test mode of the external interference channel, after the signal x(n) output by the controller is transmitted through the first channel, a response signal y 1 (n) is output to the controller.
  • the first channel refers to the first digital-to-analog converter DAC1, the first power amplifier PA1, the radio frequency switch K1, the first coupler Couple1, the transmitting antenna TX, the receiving antenna RX, the radio frequency switch K3, the second coupler Couple2, the radio frequency A communication channel is formed sequentially by the switch K2 and the first analog-to-digital converter ADC1.
  • the frequency responses of the first digital-to-analog converter DAC1, the first analog-to-digital converter ADC1, the first power amplifier PA1, the first coupler Couple1, and the second coupler Couple2 are d 1 , a 1 , p 1 , c 1 , c 2 , and assume that the responses of the three RF switches are k 1 , k 2 , k 3 , and assume that the impulse response of the channel from the transmitting antenna to the receiving antenna is H x , then:
  • the second impulse response h 2 of the second channel can be calculated in the test mode of the reconstructed channel.
  • the radio frequency interference canceller works in the test mode of reconstructing the channel, after the signal x(n) output by the controller is transmitted through the second channel, a response signal y 2 (n) is output to the controller.
  • the second channel refers to the first digital-to-analog converter DAC1, the first power amplifier PA1, the radio frequency switch K1, the first coupler Couple1, the first filter bank BPFB1, the attenuator ATT, the second analog-to-digital converter ADC2,
  • the communication channel is sequentially constituted by the digital filter PFIR, the second digital-to-analog converter DAC2, the second power amplifier PA2, the second filter bank BPFB2, the second coupler Couple2, the radio frequency switch K2, and the first analog-to-digital converter ADC1.
  • the isolation of the first coupler Couple1 and the second coupler Couple2 are s 1 and s 2 respectively
  • the frequency responses of the first filter bank BPFB1 and the second filter bank BPFB2 are b 1 and b 2 respectively
  • the attenuator ATT The frequency response of is at
  • the responses of the second analog-to-digital converter ADC2 and the second digital-to-analog converter DAC2 are a 2 , d 2 respectively
  • the frequency response of the second power amplifier PA2 is p 2 , then:
  • the coefficient of the digital filter is 1, and the corresponding frequency response is 1, so the coefficient of the digital filter is omitted in the above formula.
  • the signal transmitted by the transmitter is x
  • the reconstruction coefficient of the digital filter PFIR is h r
  • the interference signal in the second coupler is:
  • the cancellation signal conditioned by the reconstructed channel is:
  • the reconstruction coefficient of the digital filter PFIR is determined as:
  • the radio frequency interference canceller is controlled to switch from the test mode of reconstructing the channel to the normal working mode.
  • the switching method is to switch both the RF switch K1 on the transmitter side and the RF switch K2 on the receiver side to the normal working state, that is, the moving end of the RF switch K1 and the transmitter power amplifier on the transmitter side (that is, the 2 terminals in Figure 4) connection, the moving end of the radio frequency switch K2 is connected to the low noise amplifier LNA (that is, terminal 2 in FIG. 4 ) on the receiver side, and the radio frequency switch K3 is closed.
  • the attenuator ATT is also set in the attenuation state, and the filter coefficient of the digital filter PFIR is set as the reconstruction coefficient h r .
  • the power values of the first power amplifier and the second power amplifier should be greater than or equal to s+irx dBm.
  • the attenuation value of the attenuator should be irx-itx at this time.
  • the transmitter transmits the transmission signal to the first coupler Couple1 through the transmitter power amplifier, and the first coupler Couple1 sends the transmission signal through the transmission antenna TX, and the first coupler Couple1 couples the transmission signal , the obtained RF coupling signal is sent to the digital filter PFIR for conditioning via the first filter bank BPFB1, the attenuator ATT, and the second analog-to-digital converter ADC2 to obtain a digital cancellation signal, and then use the second digital-to-analog converter DAC2 to Convert the digital cancellation signal to an analog signal, use the second power amplifier PA2 to amplify the analog signal, and use the second filter bank BPFB2 to perform anti-aliasing processing on the radio frequency cancellation signal to obtain the required cancellation signal, and send the cancellation signal to
  • the second coupler Couple 2 also receives the radio frequency receiving signal from the receiving antenna RX, the radio frequency receiving signal includes an interference signal, and the second coupler Couple 2 uses the cancellation signal to eliminate the interference signal in the radio frequency receiving signal Off
  • the transmitter should stop working. On the one hand, it can ensure the safety of the circuit. This is because once the power device of the transmitter is opened, it will form a reflection, and in serious cases, it will burn out the connected Active devices; on the other hand, the RF signal on the transmitter side will leak and interfere with the test loop, resulting in inaccurate testing and affecting accuracy.
  • the online test mode is enabled.
  • the online test time of this embodiment can be controlled within 100 milliseconds to seconds, and the test time is related to the bandwidth to be tested, step
  • the input frequency is related to the number of samples per frequency point.
  • the sampling frequency of the two analog-to-digital converters and the two digital-to-analog converters reaches 900MHz, and the processing rate of the interference canceller U1 at the present stage cannot reach such a high rate. If the processing clock of the device U1 can reach 225MHz, then 4 channels of parallel FIR (Finite Impulse Response, finite-length unit impulse response) can be considered to realize the digital filter.
  • FIR Finite Impulse Response, finite-length unit impulse response
  • the output signal of the second analog-to-digital converter ADC2 is extracted, and the signal is extracted into 4 paths, which are respectively x1, x2, x3 and x4;
  • Input to four parallel filter units combine the outputs out of the four parallel filter units to obtain an output signal, and output the output signal to the second digital-to-analog converter DAC2.
  • the input power of the radio frequency interference canceller of this embodiment is 10dBm before interference cancellation, and the response after interference cancellation is within 290MHz bandwidth It can reach -30dBm, and the interference suppression ratio can reach 40dB.
  • the radio frequency interference canceller generates accurate digital filter reconstruction coefficients in the digital domain through online testing, and cancels radio frequency interference signals in real time. It has the characteristics of wide offset bandwidth, strong environmental adaptability (including scattering, multipath and other environments), high interference suppression ratio, small size, and good assembly performance. It is suitable for various waveforms such as fixed frequency, frequency hopping, and pulse.
  • the radio frequency interference canceller of this embodiment can solve the electromagnetic compatibility problem introduced by the co-site interference of the multi-function mission system, especially solve the difficult problem of canceling the co-site interference channel in the actual scene with a large time-bandwidth product, and greatly improve the broadband multiple Efficiency of functional systems.
  • radio frequency interference canceller It belongs to the same technical concept as the radio frequency interference canceller in the foregoing embodiments, and an embodiment of the present invention also provides a method for canceling radio frequency interference.
  • Fig. 8 shows a flowchart of a radio frequency interference cancellation method according to an embodiment of the present invention. As shown in Fig. 8, the method of this embodiment includes at least step S810-step S830:
  • Step S810 controlling the radio frequency interference canceller to work in the test mode of the external interference channel and the test mode of the internal reconstruction channel in sequence, and calculate the first impulse response and the second impulse response in the two test modes.
  • the radio frequency interference canceller here is the radio frequency interference canceller described in the above embodiments.
  • Step S820 calculate the reconstruction coefficient of the digital filter according to the first impulse response and the second impulse response, and load the reconstruction coefficient to the digital filter, so that the filter coefficient of the digital filter is the reconstruction coefficient.
  • Step S830 control the radio frequency interference canceller to switch to the normal working mode, perform signal conditioning processing on the radio frequency coupling signal by the digital filter in the reconstructed channel, obtain a cancellation signal, and use the cancellation signal to perform radio frequency interference cancellation.
  • the radio frequency interference canceller when the radio frequency interference canceller includes an attenuator, the radio frequency interference canceller is controlled to work sequentially in the test mode of the external interference channel and the test mode of the internal reconstruction channel, including:
  • the input end of the control splitter is connected to the output end of the first power amplifier, the output end of the combiner is connected to the input end of the first analog-to-digital converter, the input end of the combiner is connected to the receiving antenna, and the digital filter is controlled
  • the filter coefficient of 0 is 0, and the attenuator is in the straight-through state.
  • the radio frequency interference canceller works in the test mode of the external interference channel;
  • the input terminal of the control combiner is disconnected from the receiving antenna, and the filter coefficient of the digital filter is controlled to be 1.
  • the filter coefficient of the digital filter is 1, and when the attenuator is in the straight-through state, the radio frequency interference canceller works in the test mode of the internal reconstruction channel.
  • controlling the radio frequency interference canceller to switch to a normal working mode includes:
  • the input end of the control splitter is connected to the power amplifier of the transmitter, the output end of the combiner is connected to the low noise amplifier on the receiver side, the input end of the combiner is connected to the receiving antenna, and the filter coefficient of the control digital filter is heavy configuration coefficient, the attenuator is in attenuation state.
  • the radio frequency interference canceller works in a normal working mode.
  • the first impulse response and the second impulse response are calculated for two test modes, including:
  • the radio frequency interference canceller works in the test mode of the external interference channel, generate and control the training signal source to output test signals at each set frequency point of the interference cancellation frequency band; collect the first response of each set frequency point received by the controller signal; perform Fourier transform on the test signal and the first response signal of each set frequency point to obtain the frequency domain test signal and the first frequency domain response signal, and calculate the second frequency domain test signal and the first frequency domain response signal according to the frequency domain test signal and the first frequency domain response signal The first frequency domain response of a channel;
  • the radio frequency interference canceller When the radio frequency interference canceller works in the test mode of the internal reconstruction channel, it generates and controls the training signal source to output the test signal at each set frequency point of the interference cancellation frequency band; the acquisition controller receives the second signal of each set frequency point Response signal; perform Fourier transform on the test signal and the second response signal of each set frequency point to obtain the frequency domain test signal and the second frequency domain response signal, and calculate the frequency domain test signal and the second frequency domain response signal The second frequency domain response of the second channel.
  • the reconstruction coefficient of the digital filter is calculated according to the first impulse response and the second impulse response, including:
  • Inverse Fourier transform is performed on the frequency domain reconstruction response, and the inverse Fourier transform value is intercepted according to the length of the digital filter to obtain the time domain reconstruction coefficient of the digital filter.
  • the method in FIG. 8 further includes:
  • the attenuation value of the attenuator in normal working mode according to the maximum input interference power of the receiver and the power of the transmitter. Specifically, the difference between the maximum input interference power of the receiver and the power of the transmitter is the attenuation value of the attenuator.
  • the radio frequency interference cancellation method of the embodiment of the present invention controls the connection state between the receiving antenna and the combiner by controlling the connection object of the receiving end of the splitter and the connection object of the output end of the combiner, and correspondingly controls the digital filter
  • the conduction state of the radio frequency interference canceller can make the radio frequency interference canceller work in different modes.
  • the controller can calculate the impulse response of the external interference channel and the impulse response of the internal cancellation channel through the corresponding operating mode, and calculate the digital filter based on these two impulse responses.
  • the reconstruction coefficients of the filter are loaded into the digital filter, so that the cancellation channel where the digital filter is located can reconstruct the cancellation signal of the interference signal in real time based on the radio frequency coupling signal, and the radio frequency interference cancellation is performed based on the cancellation signal.
  • first, second, third, etc. may be used in the present invention to describe various information, the information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of the present invention, first information may also be called second information, and similarly, second information may also be called first information.
  • modules in the device in the embodiment can be adaptively changed and arranged in one or more devices different from the embodiment.
  • Modules or units or components in the embodiments may be combined into one module or unit or component, and furthermore may be divided into a plurality of sub-modules or sub-units or sub-assemblies.
  • All features disclosed in this specification including accompanying claims, abstract and drawings) and any method or method so disclosed may be used in any combination, except that at least some of such features and/or processes or units are mutually exclusive. All processes or units of equipment are combined.
  • Each feature disclosed in this specification may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
  • the various component embodiments of the present invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof.
  • a microprocessor or a digital signal processor (DSP) can be used in practice to implement some or all functions of some or all components in the sports training device according to the embodiment of the present invention.
  • the present invention can also be implemented as an apparatus or an apparatus program (for example, a computer program and a computer program product) for performing a part or all of the methods described herein.
  • Such a program for realizing the present invention may be stored on a computer-readable medium, or may be in the form of one or more signals.
  • Such a signal may be downloaded from an Internet site, or provided on a carrier signal, or provided in any other form.

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Abstract

本发明公开了一种射频干扰抵消器及方法。射频干扰抵消器包括：控制器、第一功率放大器、数字滤波器、第二功率放大器、第一模数转换器、第二模数转换器、第一数模转换器、第二数模转换器、分路器和合路器；分路器与发射机功放和第一功率放大器选通连接，分路器的输出端与发射天线连接，分路器的耦合端与第二模数转换器连接；控制器、第一数模转换器和第一功率放大器顺次连接；第二模数转换器、数字滤波器、第二数模转换器、第二功率放大器顺次连接，第二功率放大器还连接合路器的耦合端，合路器的输入端可断开连接接收天线，合路器的输出端与第一模数转换器和低噪声放大器选通连接，第一模数转换器还连接控制器；数字滤波器还连接控制器。

Description

一种射频干扰抵消器及方法
相关申请的交叉引用
本申请要求中国电子科技集团公司第三十六研究所于2021年12月08日提交的、发明名称为“一种射频干扰抵消器及方法”的、中国专利申请号“202111491614.0”的优先权。
技术领域
本发明涉及信号处理技术领域，具体涉及一种射频干扰抵消器及方法。
背景技术
雷达、通信、电子战等多功能任务系统在同一任务平台上存在用频交叠、空间拥挤、强弱信号反差巨大等现象。当发射机工作时，如雷达、通信、电子干扰等，会对同一频段的接收设备，如电子侦察、信号情报、通信接收等，形成强同址干扰，造成严重的电磁兼容问题，大大降低任务效能。
射频干扰抵消器的作用就是利用同址干扰信号的相干性，通过电路和算法重构干扰信号，在接收机侧有源抵消掉该干扰信号。干扰信号带宽越宽，干扰信道的延迟泄露越大，抵消难度越大。所谓延迟泄露是指实际干扰信号经不同发射路径引入的延迟差，包括散射和多径等。
为此，引入时间带宽积(Time-Bandwidth Product，TBP)，就是干扰信道带宽与干扰信道延迟泄露的乘积，来衡量射频干扰抵消的难度。时间带宽积越大，射频干扰抵消器越难以被精确重构。
目前，宽带射频干扰抵消主要采用抽头延时线(TDL，Tapped Delay Line)方案，基本原理是通过模拟延时线、调相器和模拟衰减器构成射频干扰重构的基本单元(又称为抽头)，并对每个抽头的时延、幅度、相位进行调节来重构同址干扰信道，当重构信道与干扰信道精确匹配时，宽带射频干扰信号可以完全抵消。但是，TDL方案存在以下问题：
1)TDL采用的是模拟调节器件，比如延时线、衰减器、移相器等，精度不高；
2)TDL抽头数有限，一般为8个抽头，调节精度有限，很难高精度匹配复杂信道响应，不能对大TBP值场景进行调节。这是因为在发射机干扰信号到接收机的总的延迟泄露与信号带宽的乘积大于1时，对重构滤波器的精度和抽头数提出很高要求，按现有TDL方案无法实现抵消。
3)TDL随着抽头数的增加会引入高插入损耗，由此增加有源放大会引入新的噪声。
发明内容
有鉴于此，针对同平台多任务系统环境下发射机对同频段接收机的同址干扰，本发明的主要目的在于提供了一种射频干扰抵消器及方法，以解决现有的TDL方案在大时间带宽积应用场景下无法精确重构抵消信号的问题。
依据本发明的第一方面，提供了一种射频干扰抵消器，包括：控制器、第一功率放 大器、数字滤波器、第二功率放大器、第一模数转换器、第二模数转换器、第一数模转换器、第二数模转换器、分路器和合路器；
控制器的输出端与第一数模转换器的输入端连接，第一数模转换器的输出端与第一功率放大器的输入端连接；
第二模数转换器、数字滤波器、第二数模转换器、第二功率放大器顺次连接，第二功率放大器的输出端连接合路器的耦合端，合路器的输入端可断开连接接收天线，合路器的输出端与第一模数转换器的输入端和接收机侧的低噪声放大器选通连接，第一模数转换器的输出端与控制器的输入端连接；
分路器的输入端与发射机功放和第一功率放大器的输出端选通连接，分路器的输出端与发射天线连接，分路器的耦合端与第二模数转换器的输入端连接；数字滤波器还连接控制器的控制端；
控制器计算数字滤波器的重构系数，并将重构系数加载到数字滤波器中，通过加载了重构系数的数字滤波器调理出抵消信号，对射频接收信号中的干扰信号进行射频干扰抵消。
依据本发明的第二方面，提供了一种射频干扰抵消方法，包括：
控制射频干扰抵消器依次工作在外部干扰信道的测试模式和抵消信道的测试模式，并计算出两个测试模式下通道第一冲击响应和第二冲击响应；其中，该射频干扰抵消器为上述射频干扰抵消器；
根据第一冲击响应和第二冲击响应，计算出数字滤波器的重构系数，并将重构系数加载到数字滤波器；
控制射频干扰抵消器切换到正常工作模式，由重构信道中的数字滤波器对射频耦合信号进行信号处理，得到抵消信号，利用所述抵消信号对射频接收信号中的干扰信号进行射频干扰抵消。
本发明采用的上述至少一个技术方案能够达到以下有益效果：
本发明实施例提供的射频干扰抵消器是通过分路器、两个模数转换器、两个数模转换器、数字滤波器、两个功率放大器和合路器建立重构信道，重构信道中数字滤波器的系数是控制器基于数字信号处理得到的，且抵消信号是由数字滤波器在数字域调理出的，即本实施例的射频干扰抵消器可以在数字域内生成精准的数字滤波器的系数，由数字滤波器在数字域调理出高精度抵消信号，实时地对射频干扰信号进行抵消。
数字滤波器的重构方式和精度决定了抵消精度。由于数字域处理无论精度(数字位宽)还是延时深度(抽头数)都大幅高于模拟域的TDL方式，具有抵消带宽宽、环境适应能力强(包括散射、多径等环境)、干扰抑制比高、体积小、装配性能好等特点，适应定频、跳频、脉冲等各种波形。因此通过本实施例的射频干扰抵消器，可以解决多功能任务系统由同址干扰引入的电磁兼容难题，尤其解决了同址干扰信道在实际大时间带宽积场景下抵消困难的难题，提升对干扰信号的抵消效果。
另外，本实施例是通过重构信道对射频耦合信号进行调理，并非直接针对宽带信号自适应调理，不受信号波形、带宽的影响，不会出现鼓包、底噪抬升等现象，在宽带信号抵消时具有较强的鲁棒性。上述说明仅是本发明技术方案的概述，为了能够更清楚了解本发明的技术手段，而可依照说明书的内容予以实施，并且为了让本发明的上述和其它目的、特征和优点能够更明显易懂，以下特举本发明的具体实施方式。
附图说明
通过阅读下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本发明的限制。而且在整个附图中，用相同的参考符号表示相同的部件。在附图中：
图1示出了根据本发明一个实施例的一种射频干扰抵消器的结构框图；
图2示出了根据本发明一个实施例的工作在外部干扰信道的测试模式下的射频干扰抵消器的电路示意图；
图3示出了根据本发明一个实施例的工作在内部重构信道的测试模式下的射频干扰抵消器的电路示意图；
图4示出了根据本发明一个实施例的工作在正常工作模式下的射频干扰抵消器的电路示意图；
图5示出了根据本发明一个实施例的数字滤波器的并行FIR结构示意图；
图6示出了根据本发明一个实施例的射频干扰抵消器在干扰抵消前的网络分析仪显示的频率响应实测图(测试中输入端增加30dB保护衰减器)；
图7示出了根据本发明一个实施例的射频干扰抵消器在干扰抵消后的网络分析仪显示的频率响应实测图(测试中输入端增加30dB保护衰减器)；
图8示出了根据本发明一个实施例的一种射频干扰抵消方法流程图。
具体实施方式
下面将参照附图更详细地描述本发明的示例性实施例。提供这些实施例是为了能够更透彻地理解本发明，并且能够将本发明的范围完整的传达给本领域的技术人员。虽然附图中显示了本发明的示例性实施例，然而应当理解，可以以各种形式实现本发明而不应被这里阐述的实施例所限制。
为便于理解本发明的技术方案，以通信电台对同平台的接收机造成同址干扰的应用场景为例。其中通信电台发射机包括发射数字处理器、数模转换器、上变频器、功率放大器以及发射天线，接收机包括接收天线、射频干扰抵消器、低噪声放大器(Low Noise Amplifier，简称LNA)、下变频器、模数转换器、数字干扰抵消装置以及接收数字处理器。
接收机接收到的射频接收信号中包括有干扰信号和有用信号，一般干扰信号的强度远大于有用信号的强度，因此需要抵消射频接收信号中的干扰信号，否则会造成接收机前端低噪声放大器等模块的阻塞。
在接收机的低噪声放大器之前，射频干扰抵消器将从发送机功率放大器放大之后耦合的射频信号作为参考信号，估计本地发射天线到接收天线的信道参数，如幅度与相位等，调节参考信号使之尽可能地接近接收信号中的干扰信号成份，从而在模拟域抵消接收天线收到的干扰信号。
以同址射频干扰抵消为应用场景，本发明实施例的基本技术构思是：设计射频重构与抵消电路，对外部干扰信道的冲击响应和内部重构信道的冲击响应进行在线测试，基于测试结果在数字域内生成高精度的数字滤波器系数，基于数字滤波器系数调整内部重构信道，利用调整后的重构信道实时地对干扰信号进行抵消。
图1示出了根据本发明一个实施例的一种射频干扰抵消器的结构框图，如图1所示，本实施例的射频干扰抵消器包括：控制器、第一功率放大器、数字滤波器、第二功率放大器、第一模数转换器(Analog to Digital Converter，简称为ADC)、第二模数转换器 (Digital to Analog Converter，简称为DAC)、第一数模转换器、第二数模转换器、分路器和合路器。
其中，控制器的输出端与第一数模转换器的输入端连接，第一数模转换器的输出端与第一功率放大器的输入端连接；
第二模数转换器、数字滤波器、第二数模转换器、第二功率放大器顺次连接，第二功率放大器的输出端连接合路器的耦合端，合路器的输入端可断开连接接收天线，合路器的输出端与第一模数转换器的输入端和接收机侧的低噪声放大器选通连接，第一模数转换器的输出端与控制器的输入端连接；分路器的输入端与发射机功放和第一功率放大器的输出端选通连接，分路器的输出端与发射天线连接，分路器的耦合端与第二模数转换器的输入端连接；数字滤波器还连接控制器的控制端；
控制器计算数字滤波器的重构系数，并将重构系数加载到数字滤波器中，通过加载了重构系数的数字滤波器调理出抵消信号，对射频接收信号中的干扰信号进行射频干扰抵消。
本实施例中，分路器从干扰信号中耦合出射频信号，作为参考信号输入给重构信道，合路器将调理出的射频抵消信号合路到合路器中，通过合路器对射频接收信号中的干扰信号进行抵消处理。第一数模转换器是用于将控制器输出的测试信号转换为模拟信号，以便于第一功率放大器对模拟信号进行功率放大；第一模数转换器是用于将合路器输出的模拟响应信号转换为数字响应信号，以便于控制器对响应信号进行数字化处理；第二模数转换器是用于将分路器输出的模拟信号转换为数字信号，以便于数字滤波器对数字信号进行调理；第二数模转换器是用于将数字滤波器调理出的数字信号转换为模拟信号，以便于第二功率放大器对模拟信号进行功率放大。第二功率放大器是将调制出的初始抵消信号进行功率放大。数字滤波器是对参考信号进行调理，得到初始抵消信号。
可以理解的是，控制器和数字滤波器是射频干扰抵消器的核心器件。
需要说明的是，图1中的实线连接线表明两个模块之间是直接电连接状态，图1中的第一种虚线连接线表明选通连接关系，第二种虚线连接线表明可断开连接关系，例如合路器的输出端侧采用的第一种虚线连接线表明合路器的输出端或者与低噪声放大器连接，或者与第一模数转换器连接；合路器的输入端侧采用的第二种虚线连接线表明合路器的输入端或者与接收天线连接，或者不与接收天线连接。
可见，图1所示的射频干扰抵消器，是通过分路器、两个模数转换器、两个数模转换器、数字滤波器、两个功率放大器和合路器建立重构信道，重构信道中数字滤波器的系数是控制器基于数字信号处理得到的，且抵消信号是由数字滤波器在数字域调理出的，即本实施例的射频干扰抵消器可以在数字域内生成精准的数字滤波器的系数，由数字滤波器在数字域调理出高精度抵消信号，实时地对射频干扰信号进行抵消。
数字滤波器的重构方式和精度决定了抵消精度。由于数字域处理无论精度(数字位宽)还是延时深度(抽头数)都大幅高于模拟域的TDL方式，具有抵消带宽宽、环境适应能力强(包括散射、多径等环境)、干扰抑制比高、体积小、装配性能好等特点，适应定频、跳频、脉冲等各种波形。通过本实施例的射频干扰抵消器，可以解决多功能任务系统由同址干扰引入的电磁兼容难题，尤其解决了同址干扰信道在实际大时间带宽积场景下抵消困难的难题，提升对干扰信号的抵消效果。
另外，本实施例是通过重构信道对射频耦合信号进行调理，并非直接针对宽带信号自适应调理，不受信号波形、带宽的影响，不会出现鼓包、底噪抬升等现象，在宽带信号抵消时具有较强的鲁棒性。本实施例中的控制器可以是射频干扰抵消器的系统控制 器，其包括中央处理器(Central Processing Unit，简称为CPU)、随机访问存储器(Random Access Memory，简称为RAM)、输入/输出接口(Output/Input Interface，简称为IO接口)等，CPU可以生成训练信号源。由于单音信号较为简单，容易产生，且单音信号在传送到第二功率放大器时，产生的时域信号幅度相较宽带噪声大，可以精确定标第二功率放大器在特定电平下的响应，提高后续数字滤波器的重构系统的计算精度。因此，本实施例的训练信号源优选为单音信号源。
本实施例利用第一数模转换器将控制器中训练信号源输出的数字信号转换成模拟信号，将模拟信号经过第一功率放大器放大后形成功率较高的射频信号，将射频信号发送给分路器进行分路处理。本实施例利用第二模数转换器将分路器发送来的射频信号转换为数字信号，并经重构滤波器对数字信号进行调理，将调理后的数字信号经过第二数模转换器生成相应的模拟信号，并利用第二功率放大器将模拟信号进行功率放大，得到射频信号。该射频信号经由合路器后，由第一模数转换器转换为数字信号发送给控制器。
在一些实施例中，控制器、第一模数转换器、第二模数转换器、第一数模转换器、第二数模转换器和数字滤波器形成专用集成电路(Application Specific Integrated Circuit，简称为ASIC)。本实施例通过将控制器、两个模数转换器、两个数模转换器和数字滤波器等核心的数字器件芯片化处理，使得射频干扰抵消器具有低时延、小型化、低成本和高性能的特点，不但便于射频干扰抵消器工业化，还能够提高射频干扰抵消器的市场竞争力。
在一些实施例中，图1中的射频干扰抵消器还包括第一开关、第二开关和第三开关。
其中第一开关的不动端连接分路器的输入端，第一开关的动端可选通连接发射机功放或选通连接第一功率放大器的输出端；
第二开关的不动端连接合路器的输出端，第二开关的动端可选通连接低噪声放大器或可选通连接第一模数转换器的输入端；
第三开关的不动端连接接收天线，第三开关的动端可断开连接合路器的输入端。
本实施例通过设置第一开关实现分路器与发射机功放、第一功率放大器的选通连接，通过设置第二开关实现合路器与低噪声放大器、第一模数转换器的选通连接，通过设置第三开关实现接收天线与合路器的可断开连接。在实际应用中，第一开关和第二开关可以为单刀双掷开关，第三开关为单刀单掷开关。
在一些实施例中，图1中的射频干扰抵消器还包括第一滤波器组、第二滤波器组和衰减器。
其中衰减器为可控衰减器，该衰减器连接在第一滤波器组和第二模数转换器之间，即衰减器的输入端连接第一滤波器组的输出端，衰减器的输出端连接第二模数转换器的输入端。
本实施例中的衰减器用于调节第二功率放大器的工作点，使之保持在线性区。
一般发射机的功放功率很大，以电台为例，功率在50～100W，甚至更大，此时第一功率放大器作为测试模式下的功率放大器，其功率理论上应该与发射机功率相当，但考虑到工程实用性，可将第一功率放大器的功率降至+20dBm，降低对有源器件的要求，并且能减少射频干扰抵消器的体积。假设发射机功率为100W(+50dBm)，则为了保证抵消信道中第二功率放大器的线性区不变，在测试模式中，衰减器的衰减值为0，正常工作模式下衰减器的衰减值为-30dB，这样既保证抵消响应回路特性不变，又大大降低射频干扰抵消器的消耗功率。
第一滤波器组连接在分路器和衰减器之间，第二滤波器组连接在第二功率放大器和 合路器之间。第一滤波器组和第二滤波器组的作用是对射频信号进行抗混叠滤波，将功率放大器的非线性(主要是谐波)限定在干扰抵消器的工作带宽内。
对于图1中的合路器和分路器，分路器用于对射频信号进行分路，合路器用于将天线信号和第二滤波器组的射频信号进行合路。实际应用中，为降低分路器和合路器对发射机发射功率的插损影响，合路器和分路器均为插损较小的耦合器。
为说明本实施例中射频干扰抵消器的工作过程，下面结合图2-图4予以说明。
参考图2-图4所示，在本实施例中，射频干扰抵消器包括射频取样单元M1和射频重构与抵消单元M2，其中射频取样单元M1由第一耦合器Couple1和射频开关K1组成，射频取样单元M1主要由无源器件组成，以小部件的形式放置于发射机功放和发射天线之间。射频重构和抵消单元M2主要由干扰抵消处理器(ASIC)U1和干扰抵消处理器U1的外围电路组成，以模块的形式放置于低噪放大器和接收天线之间。这里干扰抵消处理器U1包括控制器Controller、第一数模转换器DAC1、第二数模转换器DAC2、第一模数转换器ADC1、第二模数转换器ADC 2和数字滤波器PFIR。外围电路包括第一功率放大器PA1、第二功率放大器PA2、第一滤波器组BPFB1、第二滤波器组BPFB2、衰减器ATT、第二耦合器Couple2、射频开关K2和射频开关K3。
假定射频干扰抵消的信道工作在960～1250MHz带内，即瞬时带宽为290MHz，可以选择模数转换器和数模转换器的采样频率f s＝900MHz，滤波器组BPFB为960～1250MHz的带通滤波器。假定耦合器的耦合比为10dB，接收机输入最大干扰功率+20dBm，第一功率放大器PA1和第二功率放大器PA2功率为30dBm，发射机功率为100W，则衰减器AAT的最大衰减值为20dB。
各个元器件的连接关系参考上述实施例的描述以及参考图2-图4，需要说明的是，控制器Controller的控制端还应连接射频开关K1，K2和K3，以及连接衰减器ATT，为使图2-图4的电路简洁，控制器Controller的控制器与射频开关K1，K2，K3、衰减器ATT的连接关系未示出。
本实施例中的干扰抵消处理器U1用于完成对外部干扰信道的测试、内部重构信道的测试以及数字滤波器PFIR的重构系数计算、实时干扰抵消。下面详细说明这三个控制过程。
第一，外部干扰信道的测试。
如图2所示，控制射频干扰抵消器工作在外部干扰信道的测试模式。将发射机侧的射频开关K1和接收机侧的射频开关K2均置于测试状态，即射频开关K1的动端与第一功率放大器PA1的输出端(即图2中的1端)连接，射频开关K2的动端与第一模数转换器ADC1的输入端(即图2中的1端)连接，并将射频开关K3闭合，将衰减器ATT设置为直通状态，即设置衰减器的衰减值为0dB，将数字滤波器PFIR的滤波器系数置为0，即断开重构环路。
在此工作模式下，控制器Controller生成单音信号源，控制单音信号源在干扰抵消频段的各个设定频点输出信号x(n)给第一数模转换器DAC1，基于上述假设，单音信号源从960MHz每隔1MHz发出扫频信号直到1250MHz止。同时接收第一模数转换器ADC1发送来的响应数据y 1(n)，对各个设定频点下的信号x(n)和y 1(n)进行样点采集。
这里可以在干扰抵消频段等间隔采集各个设定频点，对于每个频点可采集4096个 样点，这里每个频点内样点数视精度和速度要求进行折中设置。样点采集完成后计算外部干扰信道的第一频域响应H 1，计算方法如下：
对每组4096个样点的x(n)和y 1(n)进行傅里叶变换，得到已知频点的复数响应值，重复以上过程直至得到整个待测试频段的频域响应值，基于所得到的频域响应值计算出此模式下第一通道的第一频域响应H 1。
第二，内部重构信道的测试以及数字滤波器的重构系数计算。
如图3所示，控制射频干扰抵消器由外部干扰信道的测试模式切换成重构信道的测试模式。切换方式是保持发射机侧的射频开关K1和接收机侧的射频开关K2均置于测试状态，即射频开关K1的动端与第一功率放大器PA1的输出端(即图3中的1端)连接，射频开关K2的动端与第一模数转换器ADC1的输入端(即图3中的1端)连接，以及保持衰减器ATT的直通状态；将射频开关K3断开，将数字滤波器PFIR的滤波器系数置为1，即使得重构环路处于直通状态。
在此工作模式下，控制器Controller控制单音信号源在各个设定频点输出信号x(n)给第一数模转换器DAC1，这里单音信号源的输出信号x(n)与外部干扰信道的测试模式下的输出信号x(n)相同，接收第一模数转换器ADC1发送来的响应数据y 2(n)，对各个设定频点下的信号x(n)和y 2(n)进行样点采集，样点采集方法与外部干扰信道的测试模式下的样点采集方法相同。采集完成后计算此测试模式下第二通道的第二频域响应H 2，计算方法如下：
对每组4096个样点的x(n)和y 2(n)进行傅里叶变换，得到已知频点的复数响应值，重复以上过程直至得到整个待测试频段的频域响应值，基于所得到的频域响应值计算出抵消信道的第二频域响应H 2。
在计算出频域响应H 2和H 1之后，就可以根据H r＝-H 1./H 2计算出数字滤波器的频域重构系数。这里“./”表示对应频点的除法，就是使各个设定频点对应的第一频域冲击响应值除以相应频点的第二频域冲击响应值，所得到的频数值的相反数(也即负数)即为频域重构系数，对该频域重构系数进行反傅里叶变换，并进行长度截取，得到数字滤波器PFIR的时域重构系数。在进行长度截取时，应根据数字滤波器的抽头数进行相应长度的截取，例如数值滤波器为64抽头，则截取长度为64抽头长度。
当然，实际应用中，也可以采用时域数据x(n)、y 1(n)、y 2(n)计算数字滤波器PFIR 的时域重构系数h r，但直接对
Figure PCTCN2022091290-appb-000001
求取，需要在时域求解卷积，计算复杂度较高。相较于时域处理方法，频域方法是将时域的卷积计算转换成频域的除法计算，然后再利用窗函数法计算时域重构系数，频域方法具有计算简单的优势。实际应用中，本领域技术人员可以灵活选择时域重构系数的计算方法。
这里说明一下数字滤波器的重构系数的推导过程。
首先，由外部干扰信道的测试模式可以计算出该测试模式下第一通道的第一冲击响应h 1。
当射频干扰抵消器工作在外部干扰信道的测试模式时，控制器中输出的信号x(n)经过第一通道传输后，输出响应信号y 1(n)给控制器。这里第一通道是指由第一数模转换器DAC1、第一功率放大器PA1、射频开关K1、第一耦合器Couple1、发射天线TX、接收天线RX、射频开关K3、第二耦合器Couple2、射频开关K2、第一模数转换器ADC1依次构成的通信信道。
假设第一数模转换器DAC1、第一模数转换器ADC1、第一功率放大器PA1、第一耦合器Couple1、第二耦合器Couple2的频率响应分别是d 1、a 1、p 1、c 1、c 2，并假设三个射频开关的响应分别是k 1、k 2、k 3，并假设发射天线到接收天线的信道的冲击响应是H x，则有：
Figure PCTCN2022091290-appb-000002
相应的，在重构信道的测试模式下的可以计算出第二通道的第二冲击响应h 2。
当射频干扰抵消器工作在重构信道的测试模式时，控制器中输出的信号x(n)经过第二通道传输后，输出响应信号y 2(n)给控制器。这里第二通道是指由第一数模转换器DAC1、第一功率放大器PA1、射频开关K1、第一耦合器Couple1、第一滤波器组BPFB1、衰减器ATT、第二模数转换器ADC2、数字滤波器PFIR、第二数模转换器DAC2、第二功率放大器PA2、第二滤波器组BPFB2、第二耦合器Couple2、射频开关K2、第一模数转换器ADC1依次构成的通信信道。
假设第一耦合器Couple1、第二耦合器Couple2的隔离度分别是s 1、s 2，第一滤波器组BPFB1和第二滤波器组BPFB2的频率响应分别是b 1、b 2，衰减器ATT的频率响应是at，第二模数转换器ADC2和第二数模转换器DAC2的响应分别是a 2、d 2，第二 功率放大器PA2的频率响应是p 2，则有：
Figure PCTCN2022091290-appb-000003
需要说明的是，此时数字滤波器的系数为1，对应的频率响应为1，因此上述式子中省略了数字滤波器的系数。
假设发射机发射信号为x，数字滤波器PFIR的重构系数是h r，则第二耦合器中的干扰信号为：
Figure PCTCN2022091290-appb-000004
由重构信道调理出的抵消信号为：
Figure PCTCN2022091290-appb-000005
当完全抵消时，则有c＝-i，可推导出：
Figure PCTCN2022091290-appb-000006
由此，确定出数字滤波器PFIR的重构系数为：
Figure PCTCN2022091290-appb-000007
第三，实时干扰抵消。
如图4所示，控制射频干扰抵消器由重构信道的测试模式切换成正常工作模式。切换方式是将发射机侧的射频开关K1和接收机侧的射频开关K2均切换成正常工作状态，即射频开关K1的动端与发射机侧的发射机功放(即图4中的2端)连接，射频开关K2的动端与接收机侧的低噪放大器LNA(即图4中的2端)连接，以及将射频开关K3闭合。还设置衰减器ATT处于衰减状态，将数字滤波器PFIR的滤波器系数置为重构系数h r。
假定耦合器的耦合比为s dB，接收机输入最大干扰功率irx dBm，则第一功率放大器和第二功率放大器的功率值均应大于或等于s+irx dBm。假设发射机功率为itx dBm，则在正常工作模式下，为保证抵消功率放大器仍工作在线性区，此时衰减器的衰减值应为irx-itx。
在正常工作模式下，发射机将发射信号经由发射机功放传输给第一耦合器Couple1，第一耦合器Couple1将发射信号经由发射天线TX发送出去，并由第一耦合器Couple1对发射信号进行耦合，将得到的射频耦合信号经由第一滤波器组BPFB1、衰减器ATT、第二模数转换器ADC2发送给数字滤波器PFIR进行调理，得到数字抵消信号，再利用第二数模转换器DAC2将数字抵消信号转换为模拟信号，利用第二功率放大器PA2对模拟信号进行功率放大，并利用第二滤波器组BPFB2对射频抵消信号进行抗混叠处理，得到所需的抵消信号，将抵消信号发送给第二耦合器Couple 2，第二耦合器Couple 2还 接收来自接收天线RX的射频接收信号，射频接收信号中包括干扰信号，第二耦合器Couple 2利用抵消信号对射频接收信号中的干扰信号进行抵消处理，由此完成整个流程。
需要说明的是，当射频干扰抵消器工作在测试模式时，发射机应停止工作，一方面可以保证电路安全，这是因为发射机的功率器件一旦开路就形成反射，严重时会烧毁后接的有源器件；另一方面，发射机侧的射频信号会产生泄露，对测试环路形成干扰，造成测试不准确，影响精度。
实际应用中，一般是在开机或需要重新进行通道测试时，使射频干扰抵消器开启在线测试模式，本实施例的在线测试时间可控制在百毫秒～秒内，测试时间与待测试带宽、步进频率和每个频点的样点数有关。
还应注意的是，本实施例中，两个模数转换器和两个数模转换器的采样频率达到900MHz，现阶段的干扰抵消器U1的处理速率还达不到这么高，假设干扰抵消器U1的处理时钟可达225MHz，则可以考虑4路并行FIR(Finite Impulse Response，有限长单位冲激响应)来实现数字滤波器。
如图5所示，对第二模数转换器ADC2的输出信号进行信号抽取，将信号抽取成4路，分别为x1，x2，x3和x4；将抽取出的4路信号按照图4中方式输入给四个并行的滤波单元，将四个并行的滤波单元的输出out进行合路处理，得到输出信号，将输出信号输出给第二数模转换器DAC2。
结合图6和图7，考虑到网络分析仪在测试中输入端增加了30dB保护衰减器，本实施例的射频干扰抵消器在干扰抵消前的输入功率为10dBm，干扰抵消后的响应在290MHz带宽下可以达到-30dBm，干扰抑制比达到40dB。
综合上述实施例，可以看出射频干扰抵消器通过在线测试，在数字域内生成精准的数字滤波器的重构系数，实时地对射频干扰信号进行抵消。具有抵消带宽宽、环境适应能力强(包括散射、多径等环境)、干扰抑制比高、体积小、装配性能好等特点，适应定频、跳频、脉冲等各种波形。通过本实施例的射频干扰抵消器，可以解决多功能任务系统由同址干扰引入的电磁兼容难题，尤其解决了同址干扰信道在实际大时间带宽积场景下抵消困难的难题，大大提升宽带多功能系统的效能。
与前述实施例中的射频干扰抵消器同属于一个技术构思，本发明实施例还提供了一种射频干扰抵消方法。
图8示出了根据本发明一个实施例的一种射频干扰抵消方法流程图，如图8所示，本实施例的方法至少包括步骤S810-步骤S830：
步骤S810，控制射频干扰抵消器依次工作在外部干扰信道的测试模式和内部重构信道的测试模式，并计算出两个测试模式下的第一冲击响应和第二冲击响应。
这里的射频干扰抵消器为上文实施例中描述的射频干扰抵消器。
步骤S820，根据第一冲击响应和第二冲击响应，计算出数字滤波器的重构系数，并将重构系数加载到数字滤波器，使数字滤波器的滤波器系数为重构系数。
步骤S830，控制射频干扰抵消器切换到正常工作模式，由重构信道中的数字滤波器对射频耦合信号进行信号调节处理，得到抵消信号，利用抵消信号进行射频干扰抵消。
在一些实施例中，当射频干扰抵消器包括衰减器时，控制射频干扰抵消器依次工作在外部干扰信道的测试模式和内部重构信道的测试模式，包括：
控制分路器的输入端与第一功率放大器的输出端连接，合路器的输出端与第一模数转换器的输入端连接，合路器的输入端与接收天线连接，控制数字滤波器的滤波器系数为0，衰减器处于直通状态。此时射频干扰抵消器工作在外部干扰信道的测试模式；
当射频干扰抵消器由外部干扰信道的测试模式切换到内部重构信道的测试模式时，控制合路器的输入端断开与接收天线的连接，并控制数字滤波器的滤波器系数为1。
也就是说，当分路器的输入端与第一功率放大器的输出端连接，合路器的输出端与第一模数转换器的输入端连接，合路器的输入端断开与接收天线连接，数字滤波器的滤波器系数为1，衰减器处于直通状态时，射频干扰抵消器工作在内部重构信道的测试模式。
在一些实施例中，控制射频干扰抵消器切换到正常工作模式，包括：
控制分路器的输入端与发射机功放连接，合路器的输出端与接收机侧的低噪声放大器连接，合路器的输入端与接收天线连接，控制数字滤波器的滤波器系数为重构系数，衰减器处于衰减状态。此时，射频干扰抵消器工作在正常工作模式。
在一些实施例中，计算出两个测试模式下的第一冲击响应和第二冲击响应，包括：
当射频干扰抵消器工作在外部干扰信道的测试模式时，生成并控制训练信号源在干扰抵消频段的各个设定频点输出测试信号；采集控制器接收到的各个设定频点的第一响应信号；对各个设定频点的测试信号和第一响应信号进行傅里叶变换，得到频域测试信号和第一频域响应信号，根据频域测试信号和第一频域响应信号计算出第一通道的第一频域响应；
当射频干扰抵消器工作在内部重构信道的测试模式时，生成并控制训练信号源在干扰抵消频段的各个设定频点输出测试信号；采集控制器接收到的各个设定频点的第二响应信号；对各个设定频点的测试信号和第二响应信号进行傅里叶变换，得到频域测试信号和第二频域响应信号，根据频域测试信号和第二频域响应信号计算出第二通道的第二频域响应。
在一些实施例中，根据第一冲击响应和第二冲击响应，计算出数字滤波器的重构系数，包括：
将各个设定频点的第一频域响应值除以相应频点的第二频域响应值，所得到的数值的相反数确定为数字滤波器的频域重构响应；
对频域重构响应进行反傅里叶变换，并根据数字滤波器的长度对反傅里叶变换值进行截取，得到数字滤波器的时域重构系数。
在一些实施例中，当射频干扰抵消器包括衰减器时，图8中的方法还包括：
根据接收机的输入最大干扰功率和发射机功率，设置正常工作模式下衰减器的衰减值。具体是接收机的输入最大干扰功率与发射机功率的差值即为衰减器的衰减值。
可见，本发明实施例的射频干扰抵消方法，通过控制分路器的接收端的连接对象、合路器的输出端的连接对象、控制接收天线与合路器之间的连接状态，并相应控制数字滤波器的导通状态可以使射频干扰抵消器工作在不同模式，控制器可以通过相应的工作模式计算出外部干扰信道的冲击响应、内部抵消信道的冲击响应，基于这两个冲击响应计算出数字滤波器的重构系数，并将重构系数加载到数字滤波器中，使得数字滤波器所在的抵消信道可以基于射频耦合信号实时重构出干扰信号的抵消信号，基于抵消信号进行射频干扰抵消。
应当理解，尽管在本发明可能采用术语第一、第二、第三等来描述各种信息，但这些信息不应限于这些术语。这些术语仅用来将同一类型的信息彼此区分开。例如，在不脱离本发明范围的情况下，第一信息也可以被称为第二信息，类似地，第二信息也可以被称为第一信息。
需要说明的是：
在此提供的算法和显示不与任何特定计算机、虚拟装置或者其它设备固有相关。各种通用装置也可以与基于在此的示教一起使用。根据上面的描述，构造这类装置所要求的结构是显而易见的。此外，本发明也不针对任何特定编程语言。应当明白，可以利用各种编程语言实现在此描述的本发明的内容，并且上面对特定语言所做的描述是为了披露本发明的最佳实施方式。
在此处所提供的说明书中，说明了大量具体细节。然而，能够理解，本发明的实施例可以在没有这些具体细节的情况下实践。在一些实例中，并未详细示出公知的方法、结构和技术，以便不模糊对本说明书的理解。
类似地，应当理解，为了精简本发明并帮助理解各个发明方面中的一个或多个，在上面对本发明的示例性实施例的描述中，本发明的各个特征有时被一起分组到单个实施例、图、或者对其的描述中。然而，并不应将该公开的方法解释成反映如下意图：即所要求保护的本发明要求比在每个权利要求中所明确记载的特征更多的特征。更确切地说，如下面的权利要求书所反映的那样，发明方面在于少于前面公开的单个实施例的所有特征。因此，遵循具体实施方式的权利要求书由此明确地并入该具体实施方式，其中每个权利要求本身都作为本发明的单独实施例。
本领域那些技术人员可以理解，可以对实施例中的设备中的模块进行自适应性地改变并且把它们设置在与该实施例不同的一个或多个设备中。可以把实施例中的模块或单元或组件组合成一个模块或单元或组件，以及此外可以把它们分成多个子模块或子单元或子组件。除了这样的特征和/或过程或者单元中的至少一些是相互排斥之外，可以采用任何组合对本说明书(包括伴随的权利要求、摘要和附图)中公开的所有特征以及如此公开的任何方法或者设备的所有过程或单元进行组合。除非另外明确陈述，本说明书(包括伴随的权利要求、摘要和附图)中公开的每个特征可以由提供相同、等同或相似目的的替代特征来代替。
此外，本领域的技术人员能够理解，尽管在此所述的一些实施例包括其它实施例中所包括的某些特征而不是其它特征，但是不同实施例的特征的组合意味着处于本发明的范围之内并且形成不同的实施例。例如，在下面的权利要求书中，所要求保护的实施例的任意之一都可以以任意的组合方式来使用。
本发明的各个部件实施例可以以硬件实现，或者以在一个或者多个处理器上运行的软件模块实现，或者以它们的组合实现。本领域的技术人员应当理解，可以在实践中使用微处理器或者数字信号处理器(DSP)来实现根据本发明实施例的运动训练装置中的一些或者全部部件的一些或者全部功能。本发明还可以实现为用于执行这里所描述的方法的一部分或者全部的设备或者装置程序(例如，计算机程序和计算机程序产品)。这样的实现本发明的程序可以存储在计算机可读介质上，或者可以具有一个或者多个信号的形式。这样的信号可以从因特网网站上下载得到，或者在载体信号上提供，或者以任何其他形式提供。
应该注意的是上述实施例对本发明进行说明而不是对本发明进行限制，并且本领域技术人员在不脱离所附权利要求的范围的情况下可设计出替换实施例。在权利要求中，不应将位于括号之间的任何参考符号构造成对权利要求的限制。单词“包含”不排除存在未列在权利要求中的元件或步骤。位于元件之前的单词“一”或“一个”不排除存在多个这样的元件。本发明可以借助于包括有若干不同元件的硬件以及借助于适当编程的计算机来实现。在列举了若干装置的单元权利要求中，这些装置中的若干个可以是通过同一个硬件项来具体体现。

Claims (10)

  1. 一种射频干扰抵消器，其特征在于，包括：控制器、第一功率放大器、数字滤波器、第二功率放大器、第一模数转换器、第二模数转换器、第一数模转换器、第二数模转换器、分路器和合路器；
    所述控制器的输出端与第一数模转换器的输入端连接，所述第一数模转换器的输出端与第一功率放大器的输入端连接；
    所述第二模数转换器、所述数字滤波器、所述第二数模转换器、所述第二功率放大器顺次连接，所述第二功率放大器的输出端连接所述合路器的耦合端，所述合路器的输入端可断开连接接收天线，所述合路器的输出端与所述第一模数转换器的输入端和接收机侧的低噪声放大器选通连接，所述第一模数转换器的输出端与所述控制器的输入端连接；
    所述分路器的输入端与发射机功放和第一功率放大器的输出端选通连接，所述分路器的输出端与发射天线连接，所述分路器的耦合端与第二模数转换器的输入端连接；
    所述数字滤波器还连接所述控制器的控制端；
    所述控制器计算所述数字滤波器的重构系数，并将所述重构系数加载到所述数字滤波器中，通过加载了所述重构系数的数字滤波器调理出抵消信号，对射频接收信号中的干扰信号进行射频干扰抵消。
  2. 根据权利要求1所述的射频干扰抵消器，其特征在于，所述控制器、所述第一模数转换器、所述第二模数转换器、所述第一数模转换器、所述第二数模转换器和所述数字滤波器形成专用集成电路。
  3. 根据权利要求1所述的射频干扰抵消器，其特征在于，还包括衰减器；
    所述衰减器为可控衰减器，所述衰减器连接在所述分路器和所述第二模数转换器之间。
  4. 根据权利要求3所述的射频干扰抵消器，其特征在于，还包括第一滤波器组和第二滤波器组；
    所述第一滤波器组连接在所述分路器和所述衰减器之间，所述第二滤波器组连接在所述第二功率放大器和所述合路器之间。
  5. 根据权利要求1所述的射频干扰抵消器，其特征在于，还包括第一开关、第二开关和第三开关；
    所述第一开关的不动端连接所述分路器的输入端，所述第一开关的动端可选通连接所述发射机功放或选通连接所述第一功率放大器的输出端；
    所述第二开关的不动端连接所述合路器的输出端，所述第二开关的动端可选通连接所述低噪声放大器或可选通连接所述第一模数转换器的输入端；
    所述第三开关的不动端连接所述接收天线，所述第三开关的动端可断开连接所述合路器的输入端。
  6. 根据权利要求1所述的射频干扰抵消器，其特征在于，所述合路器和所述分路器为耦合器。
  7. 一种射频干扰抵消方法，其特征在于，包括：
    控制射频干扰抵消器依次工作在外部干扰信道的测试模式和内部重构信道的 测试模式，并计算出两个测试模式下通道的第一冲击响应和第二冲击响应；其中，所述射频干扰抵消器为权利要求1-6任一项所述的射频干扰抵消器；
    根据第一冲击响应和第二冲击响应，计算出数字滤波器的重构系数，并将所述重构系数加载到所述数字滤波器；
    控制射频干扰抵消器切换到正常工作模式，由重构信道中的数字滤波器对射频耦合信号进行信号调节处理，得到抵消信号，利用所述抵消信号对射频接收信号中的干扰信号进行射频干扰抵消。
  8. 根据权利要求7所述的方法，其特征在于，当所述射频干扰抵消器包括衰减器时，控制射频干扰抵消器依次工作在外部干扰信道的测试模式和内部重构信道的测试模式，包括：
    控制分路器的输入端与第一功率放大器的输出端连接，合路器的输出端与第一模数转换器的输入端连接，合路器的输入端与接收天线连接，控制数字滤波器的滤波器系数为0，衰减器处于直通状态；
    当射频干扰抵消器由外部干扰信道的测试模式切换到内部重构信道的测试模式时，控制所述合路器的输入端断开与接收天线的连接，并控制数字滤波器的滤波器系数为1；
    控制射频干扰抵消器切换到正常工作模式，包括：
    控制分路器的输入端与发射机功放连接，合路器的输出端与接收机侧的低噪声放大器连接，合路器的输入端与接收天线连接，控制所述数字滤波器的滤波器系数为重构系数，所述衰减器处于衰减状态。
  9. 根据权利要求8所述的方法，其特征在于，计算出两个测试模式下通道的第一频域响应和第二频域响应，包括：
    当所述射频干扰抵消器工作在外部干扰信道的测试模式时，生成并控制训练信号源在干扰抵消频段的各个设定频点输出测试信号；采集控制器接收到的各个设定频点的第一响应信号；对各个设定频点的测试信号和第一响应信号进行傅里叶变换，得到频域测试信号和第一频域响应信号，根据所述频域测试信号和所述第一频域响应信号计算出第一通道的第一频域响应；
    当所述射频干扰抵消器工作在内部重构信道的测试模式时，控制所述训练信号源在所述各个设定频点输出测试信号；采集控制器接收到的各个设定频点的第二响应信号；对各个设定频点的测试信号和第二响应信号进行傅里叶变换，得到频域测试信号和第二频域响应信号，根据所述频域测试信号和所述第二频域响应信号计算出第二通道的第二频域响应。
  10. 根据权利要求9所述的方法，其特征在于，根据第一频域响应和第二频域响应，计算出数字滤波器的重构系数，包括：
    将各个设定频点对应的第一频域响应值除以相应频点对应的第二频域响应值，所得到的数值的相反数确定为所述数字滤波器的频域重构响应；
    对所述频域重构响应进行反傅里叶变换，并根据所述数字滤波器的长度对反傅里叶变换值进行截取，得到所述数字滤波器的时域重构系数。
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