A digital channelized radio frequency storage system

Abstract

The present invention discloses a digital channelized radio frequency storage system. The digital channelized frequency storage module of the radio frequency storage system can perform frequency domain separation on the input signal before storing it, which not only avoids the problem of traditional methods storing superimposed signals and interfering with the output signal, but also effectively avoids the problem of traditional frequency guidance methods that frequency measurement is easily interfered with when multiple signals arrive at the same time. The introduction of the digital channelized frequency storage module can support the acquisition and storage of multiple simultaneously arriving signals, thereby improving the frequency measurement accuracy, achieving the technical effect of precise frequency guidance, and can be used to counter coherent radar. At the same time, the high-speed, multi-bit A / D converter provided by the present invention, after the operating frequency enters the microwave frequency band, can directly acquire and reconstruct the signal in the intermediate frequency or radio frequency band, and maintain the subtle information characteristics such as the phase of the original signal, thereby ensuring that the output signal has good coherence, and can achieve high radio frequency storage accuracy and long signal storage time.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communications, and in particular to a digital channelized radio frequency storage system. Background Art

[0002] Digital Radio Frequency Memories (DRFM) are widely used in electronic countermeasures to generate various deceptive jamming targets and simulate complex electromagnetic environments in communication system anti-interference testing. The primary requirement for a DRFM system is to measure the operating frequency of the input signal, guide the system to store the frequency signal of interest with appropriate fidelity, and then guide the output signal frequency to the target frequency. This technology is known as frequency guidance or frequency storage technology. Key technical indicators for measuring frequency storage technology include instantaneous bandwidth, frequency storage accuracy, storage time, and false signal power.

[0003] Traditional frequency guidance techniques include RF frequency storage loops, frequency measurement, and comparison. These were effective for a specific period of time and for specific early electronic sensor devices, achieving relevant performance and considerable frequency estimation accuracy. However, these techniques share common drawbacks: significant frequency errors between the reconstructed signal and the original signal, loss of the original signal's phase information, and inability to counter modern coherent radars.

[0004] Therefore, how to provide a digital frequency storage system that can counter coherent radar has become a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0005] The purpose of the present invention is to provide a digital channelized radio frequency storage system, which can not only avoid the problem of traditional methods storing superimposed signals and interfering with the output signal, but also effectively avoid the problem of traditional frequency guidance methods that frequency measurement is easily interfered with when multiple signals arrive at the same time, thereby improving the frequency measurement accuracy and achieving the technical effect of precise frequency guidance.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A digital channelized radio frequency storage system, comprising: a down converter, an A / D converter, a digital channelized frequency storage module, an interference processing module, a D / A converter and an up converter, wherein:

[0008] The down-converter is used to down-convert the radio frequency signal to be processed into an analog intermediate frequency signal; the A / D converter is connected to the down-converter, and the A / D converter is used to convert the analog intermediate frequency signal into a digital signal; the digital channelized frequency storage module is connected to the A / D converter, and the digital channelized frequency storage module is used to perform channelized filtering on the digital signal to obtain each channel signal, extract the characteristic parameters of each channel signal, form a pulse description word for each channel signal, and store each channel signal; the interference processing module is connected to the digital channelized frequency storage module, and the interference processing module is used to perform interference processing on each channel signal according to the actual interference type to obtain an interference signal, and perform phase modulation and amplitude adjustment on the interference signal to obtain a radio frequency interference signal; the D / A converter is connected to the interference processing module, and the D / A converter is used to convert the radio frequency interference signal into an analog signal; the up-converter is connected to the D / A converter, and the up-converter is used to up-convert the analog signal into a high-frequency radio frequency signal.

[0009] Optionally, the digital channelized frequency storage module uses multiple filter groups to divide the frequency band of the digital signal into several interconnected sub-frequency bands, measures the characteristic parameters of the digital signal in each of the sub-frequency bands, and performs parameter encoding on the characteristic parameters to form pulse description words, wherein the characteristic parameters include frequency, pulse width, arrival time and / or pulse amplitude.

[0010] Optionally, the digital channelized frequency storage module performs frequency domain filtering processing on each of the channel signals based on differential characteristics of radar signals and non-radar signals and statistical criteria.

[0011] Optionally, the digital channelized frequency storage module uses a nonlinear quantization method to perform amplitude quantization and phase quantization on the channel signal.

[0012] Optionally, the radio frequency storage system further includes a receiving antenna and a transmitting antenna, wherein:

[0013] The receiving antenna is connected to the down converter, and is used to receive the radio frequency signal to be processed; the transmitting antenna is connected to the up converter, and is used to transmit the high-frequency radio frequency signal.

[0014] Optionally, the radio frequency storage system further includes a backplane, and the backplane is provided with a CPCI interface.

[0015] Optionally, the radio frequency storage system includes a field programmable gate array (FPGA), the FPGA is embedded with a DSP microprocessor, and the FPGA includes the digital channelized frequency storage module and the interference processing module.

[0016] Optionally, the FPGA transmits data through the CPCI interface.

[0017] Optionally, the local oscillator of the down converter is the same as that of the up converter.

[0018] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0019] The digital channelized radio frequency storage system provided by the present invention includes: a downconverter, an A / D converter, a digital channelized frequency storage module, an interference processing module, a D / A converter, and an upconverter. The digital channelized frequency storage module first performs channelized filtering on the digital signal output by the A / D converter to obtain each channel signal, then extracts the characteristic parameters of each channel signal to form a pulse description word for each channel signal, and finally stores each channel signal. It can be seen that the digital channelized frequency storage module of the present invention can perform frequency domain separation on the input signal before storage, which not only avoids the problem of traditional methods storing superimposed signals and interfering with the output signal, but also effectively avoids the problem of traditional frequency guidance methods that frequency measurement is easily interfered with when multiple signals arrive simultaneously. The introduction of the digital channelized frequency storage module can support the collection and storage of multiple simultaneously arriving signals, thereby improving the frequency measurement accuracy, achieving the technical effect of precise frequency guidance, and can be used to counter coherent radar.

[0020] The high-speed, multi-bit A / D converter provided in the present invention can directly acquire and reconstruct signals in the intermediate frequency or radio frequency band after the operating frequency enters the microwave frequency band, and maintain subtle information characteristics such as the phase of the original signal, thereby ensuring that the output signal has good coherence and can achieve high radio frequency storage accuracy and long signal storage time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A structural block diagram of a digital channelized radio frequency storage system provided by an embodiment of the present invention;

[0023] Figure 2 A signaling interaction diagram of a digital channelized radio frequency storage system provided by an embodiment of the present invention;

[0024] Figure 3 A structural block diagram of a digital channelized storage module in an FPGA processor provided by an embodiment of the present invention;

[0025] Figure 4 A specific flow chart of the digital channelized storage module provided by an embodiment of the present invention;

[0026] Figure 5 A diagram showing frequency measurement results of phase comparison and amplitude comparison using digital channelization processing provided in an embodiment of the present invention;

[0027] Figure 6 This is a structural block diagram of the interference processing module provided by an embodiment of the present invention in FPGA. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] The purpose of the present invention is to provide a digital channelized radio frequency storage system, which can not only avoid the problem of traditional methods storing superimposed signals and interfering with the output signal, but also effectively avoid the problem of traditional frequency guidance methods that frequency measurement is easily interfered with when multiple signals arrive at the same time, thereby improving the frequency measurement accuracy and achieving the technical effect of precise frequency guidance.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Figure 1 This is a structural block diagram of a digital channelized radio frequency storage system provided by an embodiment of the present invention. Figure 1 As shown, a digital channelized radio frequency storage system includes: a receiving antenna 101, a down converter 102, an A / D converter 103, a digital channelized frequency storage module 104, an interference processing module 105, a D / A converter 106, an up converter 107 and a transmitting antenna 108, wherein:

[0032] The receiving antenna 101 is connected to the downconverter 102 and is configured to receive the RF signal to be processed. The downconverter 102 is configured to downconvert the RF signal to be processed into an analog intermediate frequency signal. The A / D converter 103 is connected to the downconverter 102 and is configured to convert the analog intermediate frequency signal into a digital signal.

[0033] The digital channelized frequency storage module 104 is connected to the A / D converter 103 and is configured to perform channelized filtering on the digital signal to obtain signals for each channel. The digital channelized frequency storage module 104 includes a frequency domain filtering unit designed based on the differentiated characteristics of radar signals and communication signals, as well as non-radar signals such as noise, clutter, and harmonics, as well as statistical criteria, to perform frequency domain filtering on each channel signal. Simultaneously, the digital channelized frequency storage module 104 extracts characteristic parameters of each channel signal to form a pulse descriptor for each channel signal. Furthermore, the digital channelized frequency storage module 104 uses a nonlinear quantization method to perform amplitude and phase quantization on the channel signals after frequency domain filtering and stores the quantized data.

[0034] The interference processing module 105 is connected to the digital channelized frequency storage module 104. The interference processing module 105 is configured to perform interference processing on each channel signal output by the digital channelized frequency storage module 104 using a corresponding interference processing method based on the actual interference type to obtain an interference signal, and then perform phase modulation and amplitude adjustment on the interference signal to obtain a radio frequency interference signal. The D / A converter 106 is connected to the interference processing module 105 and is configured to convert the radio frequency interference signal into an analog signal. The up-converter 107 is connected to the D / A converter 106 and uses the same local oscillator as the down-converter 102 to up-convert the analog signal into a high-frequency radio frequency signal. The transmitting antenna 108 is connected to the up-converter 107 and is configured to transmit the high-frequency radio frequency signal.

[0035] In this embodiment, the RF storage system also includes a backplane and a field-programmable gate array (FPGA). The backplane is provided with a CPCI interface, and the FPGA is embedded with a DSP microprocessor. The FPGA includes a digital channelized frequency storage module 104 and an interference processing module 105. The FPGA transmits data via the CPCI interface. The digital channelized frequency storage module 104 uses multiple filter banks to divide the frequency band of the digital signal into several interconnected sub-bands, measures characteristic parameters of the digital signal within each sub-band, and encodes these characteristic parameters to form pulse descriptors. These characteristic parameters include frequency, pulse width, arrival time, and / or pulse amplitude.

[0036] Figure 2 This is a signaling interaction diagram of the digital channelized radio frequency storage system provided by the embodiment of the present invention. Figure 2As shown, the digital channelized RF storage system of this embodiment includes a signal acquisition board, a digital channelized frequency storage board, an interference processing board, and a backplane. The signal acquisition board is equipped with an A / D converter and a D / A converter, enabling both A / D and D / A conversion. The antenna and microwave component module includes a transceiver antenna, an upconverter, and a downconverter, enabling both upconversion and downconversion. The backplane, based on a CPCI bus architecture, facilitates data access between the aforementioned boards and the antenna and microwave components.

[0037] Figure 3 This is a structural block diagram of the digital channelized storage module provided by the embodiment of the present invention in the FPGA processor. Figure 3 As shown in the figure, the digital channelized storage module divides the input A / D sampling signal's frequency band into several interconnected sub-bands using numerous narrow-bandwidth filter banks. Using each sub-band as the minimum detection unit, it measures parameters such as the input signal's frequency (RF), pulse width (PW), time of arrival (TOA), and pulse amplitude (PA) within that sub-band. These parameters are then encoded to form a pulse description word (PDW) in a specific format.

[0038] Figure 4 This is a specific flow chart of the digital channelized storage module provided by the embodiment of the present invention. In the digital frequency storage process, quantization technology plays a key role in "waveform fidelity", which determines the instantaneous bandwidth, clutter suppression, dynamics and coherence. Figure 4 As shown, the digital channelized frequency storage board accesses the signal acquisition board through the processing board interface on the CPCI interface backplane, reads the intermediate frequency sampled data, and performs a fast Fourier transform (FFT) to achieve channelization. The frequency domain signal output after channelization undergoes DSP-based frequency domain filtering to remove noise, clutter, communication signals, and other non-radar signals. Simultaneously, detection and parameter estimation are performed on the channelized data, completing parameter encoding and outputting a PDW. The channelized data after frequency domain filtering is input into the DSP-based nonlinear quantization module for quantization. The quantized data is then stored in the FPGA-based signal storage module, allowing other system modules to access the stored data through the processing board interface on the CPCI board. The data storage module also controls the network interface to allow external devices to access the stored data. Furthermore, the digital channelized frequency storage board acquires reference clock 1 and, through the clock distribution circuit, generates the reference clock required by the digital channelization module and signal storage module.

[0039] In the specific implementation process, the present invention adopts a nonlinear quantization method, such as logarithmic quantization, which quantizes the logarithm of the signal amplitude. Assuming that the inputs of the I and Q channels at the i-th sampling time are x(i) and y(i), respectively, the quantization process is as follows:

[0040] (a) Calculate the amplitude A(i) and phase phi(i) at the i-th sampling moment:

[0041] A(i)=sqrt(x(i)*x(i)+y(i)*y(i));

[0042] phi(i)=atan(y(i) / x(i)).

[0043] (b) Calculate the logarithmic quantization value A_dB(i) of A(i):

[0044] A_dB(i)=10*log10(A(i)).

[0045] (c) Store the data pair A_dB(i) and phi(i) in memory.

[0046] (d) When reconstructing data, take out the data pair A_dB(i) and phi(i). Then the I path of the reconstructed data is: AI(i) = 10^(A_dB(i) / 10)*cos(phi(i)), and the Q path is: AQ(i) = 10^(A_dB(i) / 10)*sin(phi(i)).

[0047] This method can be used for both amplitude and phase quantization. It effectively improves instantaneous bandwidth and significantly enhances small signal fidelity without significantly compromising large signal storage quality, making it particularly suitable for frequency storage of low-acquisition radar signals. Furthermore, it significantly reduces the amount of data stored, effectively lowering implementation costs while maintaining the same storage depth, or improving storage depth at the same cost.

[0048] Figure 5 The frequency measurement results of phase comparison and amplitude comparison of the digital channelization processing provided in the embodiment of the present invention are shown. Figure 5 As shown, the signal-to-noise ratio is 30dB, the fast Fourier transform FFT and amplitude comparison assisted phase comparison method, the sampling frequency is 1.28GHz, the FFT length is 64, the frequency resolution is 20MHz, the mean is -0.01MHz, and the standard deviation is 0.099MHz. Under the above given conditions, the average frequency measurement error is -0.01MHz and the root mean square error is 0.099MHz, which is a great improvement over the traditional frequency measurement guidance method.

[0049] Figure 6 This is a block diagram of the interference processing module provided by the embodiment of the present invention in FPGA. Figure 6 As shown, the interference processing module can modulate and reconstruct the input PDW parameters and intermediate frequency sampling data according to the interference generation strategy to generate an interference signal.

[0050] In summary, the overall workflow of the digital channelized radio frequency storage system provided by the present invention is as follows:

[0051] 1) Down-conversion: Down-convert the RF signal received by the receiving antenna to an intermediate frequency or baseband.

[0052] 2) A / D conversion: high-precision, high-dynamic, high-fidelity digital sampling and quantization of intermediate frequency or baseband signals.

[0053] 3) Digital Channelized Storage: The digital channelized storage module processes the A / D quantized digital signal through channelization, extracts key characteristic parameters, forms pulse descriptors, and retains them for interference modulation. It also stores the processed intermediate frequency data.

[0054] 4) Interference processing: The interference processing module integrates the results of the channelized storage module, performs different operations on each type of storage sample according to different interference patterns, and synthesizes them. It then completes the control of the delay and amplitude of the output signal to form an RF interference signal.

[0055] 5) D / A conversion: The interference signal generated by the modulator passes through the parallel-to-serial conversion circuit and is converted into an analog signal through the D / A.

[0056] 6) Up-conversion: The D / A signal is up-converted to a radio frequency signal using the same local oscillator used for down-conversion.

[0057] The digital channelized RF storage system provided by the present invention features a digital channelized frequency storage module that separates the input signal in the frequency domain before storing it, avoiding the problem of traditional methods storing superimposed signals and causing interference with the output signal. This effectively avoids the problem of traditional frequency guidance methods, such as frequency measurement being susceptible to interference when multiple signals arrive simultaneously. The introduction of a digital channelized receiver supports the acquisition and storage of multiple simultaneously arriving signals, improving frequency measurement accuracy and achieving a precisely frequency-guided RF storage solution.

[0058] At the same time, the present invention performs frequency-domain filtering on the signal output by each channel of the digital channelized frequency storage module. The filter is designed by utilizing the differentiated characteristics of radar signals and non-radar signals such as communication signals, noise, clutter, and harmonics, as well as statistical criteria. This can remove false signals such as communication signals, noise, and clutter that exist in traditional digital frequency storage systems before signal storage. This improves the instantaneous operating bandwidth, increases the storage depth, and improves the main-to-noise ratio of the output signal with the same hardware overhead.

[0059] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0060] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A digital channelized radio frequency storage system, characterized in that: The radio frequency storage system includes: a receiving antenna, a transmitting antenna, a down converter, an A / D converter, a digital channelized frequency storage module, an interference processing module, a D / A converter and an up converter, wherein: The down-converter is used to down-convert the radio frequency signal to be processed into an analog intermediate frequency signal; the A / D converter is connected to the down-converter, and the A / D converter is used to convert the analog intermediate frequency signal into a digital signal; the digital channelized frequency storage module is connected to the A / D converter, and the digital channelized frequency storage module is used to perform channelized filtering on the digital signal to obtain each channel signal, extract the characteristic parameters of each channel signal, form a pulse description word for each channel signal, and store each channel signal; the interference processing module is connected to the digital channelized frequency storage module, and the interference processing module is used to perform interference processing on each channel signal according to the actual interference type to obtain an interference signal, and perform phase modulation and amplitude adjustment on the interference signal to obtain a radio frequency interference signal; the D / A converter is connected to the interference processing module, and the D / A converter is used to convert the radio frequency interference signal into an analog signal; the up-converter is connected to the D / A converter, and the up-converter is used to up-convert the analog signal into a high-frequency radio frequency signal; The digital channelized frequency storage module performs frequency domain filtering on each of the channel signals based on the differential characteristics of radar signals and non-radar signals and statistical criteria, and uses a nonlinear quantization method to perform amplitude quantization and phase quantization on the channel signals; The digital channelized frequency storage module uses multiple filter banks to divide the frequency band of the digital signal into a plurality of interconnected sub-frequency bands, measures characteristic parameters of the digital signal in each of the sub-frequency bands, and performs parameter encoding on the characteristic parameters to form a pulse description word, wherein the characteristic parameters include frequency, pulse width, arrival time, and / or pulse amplitude; The receiving antenna is connected to the down converter, and is used to receive the radio frequency signal to be processed; the transmitting antenna is connected to the up converter, and is used to transmit the high-frequency radio frequency signal.

2. The radio frequency storage system according to claim 1, wherein: The radio frequency storage system further includes a backplane, and the backplane is provided with a CPCI interface.

3. The radio frequency storage system according to claim 2, characterized in that The radio frequency storage system includes a field programmable gate array (FPGA), the FPGA is embedded with a DSP microprocessor, and the FPGA includes the digital channelized frequency storage module and the interference processing module.

4. The radio frequency storage system according to claim 3, characterized in that The FPGA performs data transmission via the CPCI interface.

5. The radio frequency storage system according to claim 1, wherein: The down converter has the same local oscillator as the up converter.

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