Method and system for testing in-band flatness of broadband linear frequency modulation signal and medium

Abstract

The invention belongs to the field of spaceborne imaging radars, and discloses a broadband linear frequency modulation signal in-band flatness testing method and system and a medium. A local oscillator signal is output through the first signal source, an intermediate frequency signal is output through the second signal source in a frequency hopping mode, the local oscillator signal and the intermediate frequency signal are processed through up-conversion, filtering, power amplification and the like in the broadband linear frequency modulation excitation module to output a radio frequency signal, and the in-band flatness response of the broadband linear frequency modulation signal is obtained by measuring the power value of the radio frequency signal. The in-band flatness is measured by adopting a signal source single-point continuous frequency hopping and power meter real-time testing method, and the power meter is an instrument for power testing and is higher in power testing accuracy and faster in response compared with a frequency spectrograph, so that the in-band flatness of the signal can be tested more accurately and quickly.

Description

Technical Field

[0001] The invention relates to the field of spaceborne imaging radars, and in particular to a method, system and medium for testing the in-band flatness of a broadband linear frequency modulation signal. Background Art

[0002] As modern radar develops towards digitalization and broadband, signal waveforms are becoming more and more complex and bandwidths are becoming wider. The signal in-band characteristics directly affect important indicators such as system resolution. In order to ensure system indicators, it is very important to accurately test and analyze characteristics such as signal flatness.

[0003] The mixer, intermediate frequency filter, RF filter, amplifier, standing wave matching and other functional circuits in the uplink signal link may affect the in-band characteristics of the linear frequency modulation excitation signal. The existing technology uses the method of signal source frequency sweep and spectrum analyzer maximum hold to measure the in-band flatness, in which the frequency in the signal source frequency sweep changes continuously, from the starting frequency to the end frequency. Because the response time of the spectrum analyzer test is long, the in-band flatness test speed is slow; and due to the influence of RF interface standing wave matching, it is difficult to meet the test accuracy requirements, but the satellite-borne radar products have very high requirements for the in-band flatness of the signal, so a method with higher accuracy and faster response for testing the in-band flatness of the signal needs to be studied urgently. Summary of the invention

[0004] In order to solve the problems in the prior art and achieve the purpose of quickly and accurately measuring the in-band flatness of a broadband linear frequency modulation signal, the present invention provides a method, system and medium for testing the in-band flatness of a broadband linear frequency modulation signal.

[0005] In the first aspect, a method for testing the in-band flatness of a broadband linear frequency modulation signal is provided, and the technical solution adopted is as follows:

[0006] The signal source 1 outputs a local oscillator signal, wherein the local oscillator signal is a high frequency signal;

[0007] The signal source 2 frequency hopping outputs the intermediate frequency signal;

[0008] The broadband linear frequency modulation excitation module processes two signals into one broadband linear frequency modulation signal, wherein the two signals include a local oscillator signal output by a signal source 1 and an intermediate frequency signal output by a frequency hopping signal source 2, and the broadband linear frequency modulation signal is a radio frequency signal;

[0009] The power value of the radio frequency signal when the second measuring signal source outputs the intermediate frequency signal of each frequency point is the in-band flatness of the broadband linear frequency modulation signal of the excitation signal corresponding to the local oscillator signal.

[0010] Furthermore, when the broadband linear frequency modulation excitation module processes two signals into one broadband linear frequency modulation signal, the method adopted is as follows:

[0011] The broadband linear frequency modulation excitation module performs up-conversion, mixing, filtering and power amplification on the two received signals, and then outputs a broadband linear frequency modulation signal, where the broadband linear frequency modulation signal is a radio frequency signal.

[0012] Furthermore, the intermediate frequency signal covers various frequency points of the broadband linear frequency modulation signal and changes continuously at equal frequency intervals within the test bandwidth.

[0013] Furthermore, the signal source 1 changes the frequency of the local oscillator signal, and measures the power value of the radio frequency signal when the signal source 2 outputs the intermediate frequency signal of each frequency point, so as to obtain the in-band flatness within the radio frequency sub-band.

[0014] In a second aspect, a system for measuring the in-band flatness of a broadband linear frequency modulation signal is provided, wherein the system is used to implement the method for measuring the in-band flatness of a broadband linear frequency modulation signal according to the first aspect, and the system comprises the following parts:

[0015] Signal source 1, used for outputting a local oscillator signal, which is a high-frequency signal;

[0016] Signal source 2, used for outputting frequency-hopping intermediate frequency signals;

[0017] The broadband linear frequency modulation excitation module is used to process two signals and output a broadband linear frequency modulation signal, wherein the broadband linear frequency modulation signal is a radio frequency signal, and the two signals include:

[0018] The local oscillator signal output by the signal source 1 is a high-frequency signal;

[0019] The intermediate frequency signal of the second frequency hopping output of the signal source;

[0020] A power meter, used to measure the power value of the radio frequency signal;

[0021] A power supply for supplying power to various parts of the broadband linear frequency modulation signal in-band flatness test system;

[0022] The computer starts the automatic test process through the user interface control, completes the test status control and data collection, and forms the final analysis results;

[0023] The data acquisition board is used to form the working state control code of the broadband linear frequency modulation excitation module, and at the same time collect the working state of the test system and send it to the computer for monitoring.

[0024] According to a third aspect, a medium is provided, wherein the medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps in the method according to the first aspect.

[0025] The beneficial effects of the present invention are as follows:

[0026] The existing technology uses the method of signal source frequency sweep and spectrum analyzer maximum hold to measure the in-band flatness, that is, the output of the signal source is in a frequency sweep mode, and the frequency changes continuously, from the starting frequency to the end frequency, so the response time to certain specific frequencies is long. The energy of signals of different frequencies is determined by measuring the energy distribution of signals of different frequencies by the spectrum analyzer. In addition, due to the influence of RF interface standing wave matching, it is difficult to quickly complete the in-band flatness test in the existing technology and meet the test accuracy requirements.

[0027] The present invention adopts the method of single-point frequency hopping of signal source and real-time testing of power meter to measure the in-band flatness. The output signal source frequency points hop continuously at equal intervals, so the response to certain specific frequencies is fast. The power meter is an instrument for power testing, and has higher accuracy and faster response than the spectrum analyzer for testing power. Therefore, the test of signal in-band flatness can be completed more accurately and quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a test flow of the in-band flatness of a broadband linear frequency modulation signal according to an embodiment of the present invention;

[0029] Figure 2 It is the testing principle of the in-band flatness of the broadband linear frequency modulation signal of the embodiment of the present invention;

[0030] Figure 3 This is the processing flow of the broadband linear frequency modulation signal in-band flatness testing system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described below.

[0032] For satellite-borne imaging products, large signal bandwidth and high flatness are required. This application improves the test method, adopts single-point frequency hopping of the signal source and real-time testing of the power meter, and completes the broadband signal flatness test quickly and accurately.

[0033] The test method provided by the present invention is based on network communication, instrument control and acquisition, and data analysis. Through the TCP / IP protocol, the computer communicates with the power meter, signal source, and data acquisition board to complete the flatness response test. The test principle is as follows: Figure 2As shown. Among them, the signal source 1 is controlled to output the corresponding local oscillator signal according to the working frequency of the broadband linear frequency modulation excitation module; the signal source 2 generates intermediate frequency signals of several frequency points covering the broadband linear frequency modulation signal by frequency hopping; the broadband linear frequency modulation excitation module is the module to be tested, which completes the filtering, up-conversion, amplification, sub-band filtering and other functions of the broadband linear frequency modulation signal, and outputs the radio frequency signal; the power meter reads the power value of the radio frequency signal according to the current working frequency of the broadband linear frequency modulation excitation module, and the computer reads the test value of the power meter through network communication; the computer controls the start of the automatic test process through the user interface, completes the control and data collection of the test status, and forms the final analysis result; the data acquisition board receives the decoding of the computer TCP / IP protocol instructions, forms the control code of the broadband linear frequency modulation excitation module, and collects the working status at the same time and sends it to the computer for monitoring.

[0034] Embodiment 1:

[0035] The present invention provides a method for testing the in-band flatness of a broadband linear frequency modulation signal. The testing process is as follows: Figure 1 As shown, the details are as follows:

[0036] S1, signal source 1 outputs a local oscillator signal, wherein the local oscillator signal is a high frequency signal;

[0037] According to the test principle, after the test environment is powered on, the data acquisition board controls the working state of the broadband linear frequency modulation excitation module according to the test state, including frequency switching, receiving and transmitting state, etc. The computer controls the signal source to output the local oscillator signal through network communication. The local oscillator signal is a high-frequency signal.

[0038] S2, signal source two frequency hopping output intermediate frequency signal

[0039] The computer and the data acquisition board perform status control and data interaction, and control the signal source to generate an intermediate frequency signal through TCP / IP network communication. The frequency range of the intermediate frequency signal is 3~3.8GHz, the frequency hopping frequency interval is 1MHz, and a total of 801 frequency points are output, covering the 800MHz bandwidth of the broadband linear frequency modulation signal, and the frequency interval changes continuously within the test bandwidth.

[0040] S3, broadband linear frequency modulation excitation module processes two signals into one broadband linear frequency modulation signal

[0041] The broadband linear frequency modulation excitation module processes two signals into one broadband linear frequency modulation signal, and the two signals include a local oscillator signal output by signal source one and an intermediate frequency signal output by frequency hopping of signal source two, and the broadband linear frequency modulation signal is a radio frequency signal; when the broadband linear frequency modulation excitation module processes two signals into one radio frequency signal, the specific method is as follows: the broadband linear frequency modulation excitation module performs up-conversion mixing, filtering, power amplification and other processing on the intermediate frequency signal output by frequency hopping of the received signal source two and the local oscillator signal output by the signal source one, and then outputs the radio frequency signal.

[0042] S4. Measure the power value of the radio frequency signal when the second signal source outputs the intermediate frequency signal at each frequency point, that is, the in-band flatness of the broadband linear frequency modulation signal of the excitation signal corresponding to the local oscillator signal.

[0043] The power meter reads the power values ​​of the local oscillator signal output by signal source one and the RF signal output by the intermediate frequency signal output by frequency hopping of signal source two after up-conversion according to the current working frequency of the broadband linear frequency modulation excitation module (i.e., the frequency of the local oscillator signal), and the test value of the power meter is read out by a computer through network communication; the corresponding RF signal power values ​​when the signal source two outputs 801 frequency hopping frequencies are measured respectively, and the in-band flatness of the broadband linear frequency modulation signal with a bandwidth of 800MHz corresponding to the excitation signal of the local oscillator signal is obtained.

[0044] Embodiment 2:

[0045] On the basis of Example 1, signal source 1 changes the frequency of the local oscillator signal, and repeats the steps in Example 1 according to the number of local oscillator frequencies tested in the linear frequency modulation signal band, to measure the in-band flatness of the broadband linear frequency modulation signal corresponding to the excitation signal at each local oscillator frequency, that is, the in-band flatness in the RF sub-band.

[0046] The present invention also provides a broadband linear frequency modulation signal in-band flatness test system, comprising the following parts:

[0047] Signal source 1 is used to output a local oscillator signal, and the local oscillator signal is a high-frequency signal; the signal source 1 is controlled to output a corresponding local oscillator signal according to the working frequency of the broadband linear frequency modulation excitation module;

[0048] Signal source 2 is used for frequency hopping to output intermediate frequency signals; signal source 2 frequency hopping generates a plurality of frequency points covering the broadband linear frequency modulation signal; the frequency range of the intermediate frequency signal is 3-3.8 GHz, the frequency hopping frequency interval is 1 MHz, and a total of 801 frequency points are output, covering the 800 MHz bandwidth of the broadband linear frequency modulation signal;

[0049] The broadband linear frequency modulation excitation module is used to output the radio frequency signal after up-converting the local oscillator signal output by the signal source 1 and the intermediate frequency signal output by the signal source 2; the broadband linear frequency modulation excitation module is the module to be tested, which completes the functions of filtering, up-conversion, amplification, sub-band filtering, etc. of the broadband linear frequency modulation signal of the intermediate frequency;

[0050] The power meter tests the power value of the RF signal when the signal source 2 outputs the intermediate frequency signal of each frequency point in real time according to the current operating frequency point of the broadband linear frequency modulation excitation module. The computer reads the test value of the power meter through network communication, which is the in-band flatness of the broadband linear frequency modulation signal of the excitation signal corresponding to the local oscillator signal.

[0051] The data acquisition board completes the protocol communication with the computer, converts it into the state control code of the broadband linear frequency modulation excitation module, and collects and monitors the working status of each part of the test system.

[0052] The computer starts the automatic test process through the user interface control, completes the control of the test system test state and data collection, and forms the final in-band flatness analysis result based on the test data;

[0053] Power supply, used to power various parts of the in-band flatness test system.

[0054] When the broadband linear frequency modulation signal in-band flatness test system performs an in-band flatness test on the broadband linear frequency modulation excitation module under test, first, the power module supplies power to each module and starts the test; the data acquisition board controls the working state (frequency switching, receiving and transmitting state, etc.) of the broadband linear frequency modulation excitation module according to the test state, and the computer controls the signal source 1 to output the local oscillator signal and controls the signal source 2 to output the intermediate frequency signal frequency through network communication; the broadband linear frequency modulation excitation module outputs a broadband linear frequency modulation signal after up-conversion, filtering, etc. of the local oscillator signal output by the signal source 1 and the intermediate frequency signal signal output by the signal source 2 through frequency hopping, and the broadband linear frequency modulation signal is a radio frequency signal; the computer reads the radio frequency signal power value when the signal source 2 outputs the intermediate frequency signal of each frequency point under the current local oscillator signal of the power meter through network communication; according to the number of test frequencies in the broadband linear frequency modulation signal band, the local oscillator signal frequency of the signal source 1 is changed, and the radio frequency signal power value when the signal source 2 outputs the intermediate frequency signal of each frequency point is measured, so that the in-band flatness in the radio frequency sub-band can be measured.

[0055] The processing flow of the broadband linear frequency modulation signal in-band flatness test system is as follows: Figure 3 shown.

[0056] a) Connect each instrument (including signal source 1, signal source 2, data acquisition board, computer and power meter) to determine whether the instrument communication is normal. If the TCP / IP handshake between the computer, power meter and data acquisition board is normal, proceed to the next step, otherwise the system waits.

[0057] b) Select the in-band flatness test on the test interface on the computer, and set the linear frequency modulation signal bandwidth, local oscillator signal frequency, etc.

[0058] c) Start cycle test time;

[0059] d) Form a test table according to the test items, including linear frequency modulation signal bandwidth, flatness test results, etc.;

[0060] e) Start a single test;

[0061] f) The computer controls the working status of the broadband linear frequency modulation excitation module, including frequency switching, receiving and transmitting status, etc.

[0062] g) Trigger single frequency test;

[0063] h) controlling the signal source to output a signal of a corresponding frequency, including controlling the signal source 1 to output a local oscillator signal and controlling the signal source 2 to output an intermediate frequency signal;

[0064] i) The computer reads the power test value of the power meter;

[0065] j) Repeat step hi according to the number of test frequency points in the broadband linear frequency modulation signal band, so as to measure the in-band flatness of the broadband linear frequency modulation signal of the excitation signal corresponding to the current local oscillator signal;

[0066] k) Repeat steps f to i to measure the RF signal power value when the signal source 2 outputs the intermediate frequency signal at each frequency point when the local oscillator signal has different frequency points.

[0067] l) Repeat steps d to i to perform a cyclic test;

[0068] m) After the set cycle test time is over, by analyzing the RF signal power value when the signal source 2 outputs the intermediate frequency signal at each frequency point at different frequencies of the local oscillator signal, the stability of the flatness change of the broadband linear frequency modulation signal band of the excitation signal within the cycle test time is obtained.

[0069] The present invention also provides a storage medium, which stores one or more programs. The one or more programs can be executed by one or more processors to implement the steps in the method for testing the in-band flatness of a broadband linear frequency modulation signal.

[0070] Although the present invention has been disclosed as above with preferred embodiments, the embodiments are not intended to limit the present invention. Any equivalent changes or modifications made without departing from the spirit and scope of the present invention also belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the content defined by the claims of this application.

Claims

1. A method for testing the in-band flatness of a broadband linear frequency modulation signal, characterized in that: The steps include: The signal source 1 outputs a local oscillator signal, wherein the local oscillator signal is a high frequency signal; The signal source 2 frequency hopping outputs the intermediate frequency signal; The broadband linear frequency modulation excitation module processes two signals into one broadband linear frequency modulation signal, wherein the two signals include a local oscillator signal output by a signal source 1 and an intermediate frequency signal output by a frequency hopping signal source 2, and the broadband linear frequency modulation signal is a radio frequency signal; The power value of the radio frequency signal when the second measuring signal source outputs the intermediate frequency signal of each frequency point is the in-band flatness of the broadband linear frequency modulation signal of the excitation signal corresponding to the local oscillator signal.

2. The method for testing the in-band flatness of a broadband linear frequency modulation signal according to claim 1, characterized in that: When the broadband linear frequency modulation excitation module processes two signals into one broadband linear frequency modulation signal, the method used is as follows: The broadband linear frequency modulation excitation module performs up-conversion, mixing, filtering and power amplification on the two received signals, and then outputs a broadband linear frequency modulation signal, where the broadband linear frequency modulation signal is a radio frequency signal.

3. The method for testing the in-band flatness of a broadband linear frequency modulation signal according to claim 2, characterized in that: The intermediate frequency signal covers each frequency point of the broadband linear frequency modulation signal and changes continuously at equal frequency intervals within the test bandwidth.

4. The method for testing the in-band flatness of a broadband linear frequency modulation signal according to claim 3, characterized in that: The signal source 1 changes the frequency of the local oscillator signal, and measures the power value of the radio frequency signal when the signal source 2 outputs the intermediate frequency signal of each frequency point, so as to obtain the in-band flatness in the radio frequency sub-band.

5. A system for testing the in-band flatness of a broadband linear frequency modulation signal, characterized in that: The system is used to implement the method for testing the in-band flatness of a broadband linear frequency modulation signal as claimed in claim 1, and the system comprises the following parts: Signal source 1, used for outputting a local oscillator signal, which is a high-frequency signal; Signal source 2, used for outputting frequency-hopping intermediate frequency signals; The broadband linear frequency modulation excitation module is used to process two signals and output a broadband linear frequency modulation signal, wherein the broadband linear frequency modulation signal is a radio frequency signal, and the two signals include: The local oscillator signal output by the signal source 1 is a high-frequency signal; The intermediate frequency signal of the second frequency hopping output of the signal source; A power meter, used to measure the power value of the radio frequency signal; A power supply for supplying power to various parts of the broadband linear frequency modulation signal in-band flatness test system; The computer starts the automatic test process through the user interface control, completes the test status control and data collection, and forms the final analysis results; The data acquisition board is used to form the working state control code of the broadband linear frequency modulation excitation module, and at the same time collect the working state of the test system and send it to the computer for monitoring.

6. A storage medium, characterized in that: The storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps in the method as claimed in any one of claims 1 to 4.

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