CN112924949A - System and method for generating chaos radar transmitting signal in real time based on FPGA - Google Patents
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Abstract
The invention discloses a chaos radar transmitting signal real-time generating system and a method based on FPGA, the system comprises: the device comprises a baseband IQ path waveform generation module, a DAC module, an IQ modulator, a transmitting up-conversion module and a frequency source; the baseband IQ path waveform generation module is realized by an FPGA and is used for respectively generating baseband I path and Q path waveform data of the chaotic radar; the DAC module is used for respectively carrying out digital-to-analog conversion on the waveform data of the baseband I path and the baseband Q path to obtain analog waveforms of the baseband I path and the baseband Q path; the IQ modulator is used for carrying out IQ modulation on analog waveforms of the I path and the Q path of the baseband in combination with an intermediate frequency local oscillator signal to generate an intermediate frequency chaotic signal; the transmitting up-conversion module is used for mixing an intermediate frequency chaotic signal and a radio frequency local oscillator signal to generate a radio frequency chaotic signal; and the frequency source is used for providing a working clock of the FPGA, an intermediate frequency local oscillator signal and a radio frequency local oscillator signal.
Description
Technical Field
The invention relates to the technical field of chaotic radar signal processing, in particular to a system and a method for generating chaotic radar transmitting signals in real time based on an FPGA.
Background
The Noise Radar adopts random or pseudo-random signals as transmitting waveforms, and is currently applied to multiple fields such as military and civil use (reference [1] patent CN104777461A, a method and a system for generating broadband chaotic Radar signals with randomly hopping carrier frequencies; reference [2] Krzysztoff Kulpa, Signal Processing in Noise wave Radar, ISBN: 9781608076611).
In noisy radar, the generation of random or pseudo-random transmitted signals is a key technique. Compared with a common thermal noise signal, the chaotic signal is easier to generate and control. A chaotic signal is a pseudo-random signal generated by a deterministic system. The chaotic signal is very sensitive to an initial value, and the slight change of the initial value can cause great difference of subsequent signals; and the chaotic signal has the characteristics of non-periodicity and unpredictability. The chaotic signal is adopted as the transmitting signal of the radar, so that the advantages of low interception probability characteristic, effective spectrum utilization and the like are achieved.
A Field Programmable Gate Array (FPGA) has a series of advantages such as large capacity, high speed, and high integration level, and is increasingly applied to radar control, digital signal processing, and the like. Therefore, generating the chaotic signal required by radar transmission in real time based on the FPGA will bring new technological changes.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a system and a method for generating a chaos radar transmitting signal in real time based on an FPGA.
In order to achieve the above object, the present invention provides a chaos radar transmitting signal real-time generating system based on an FPGA, the system comprising: the device comprises a baseband IQ path waveform generation module, a DAC module, an IQ modulator, a transmitting up-conversion module and a frequency source; wherein the content of the first and second substances,
the baseband IQ path waveform generation module is realized by an FPGA and is used for respectively generating baseband I path waveform data and baseband Q path waveform data of the chaotic radar and inputting the baseband I path waveform data and the baseband Q path waveform data into the DAC module;
the DAC module is used for respectively carrying out digital-to-analog conversion on the baseband I path waveform data and the baseband Q path waveform data to obtain a baseband I path analog waveform and a baseband Q path analog waveform, and inputting the baseband I path analog waveform and the baseband Q path analog waveform into the IQ modulator;
the IQ modulator is used for carrying out IQ modulation on the baseband I path analog waveform and the baseband Q path analog waveform in combination with the intermediate frequency local oscillator signal, generating an intermediate frequency chaotic signal and inputting the intermediate frequency chaotic signal into the transmitting up-conversion module;
the transmitting up-conversion module is used for mixing the intermediate frequency chaotic signal and the radio frequency local oscillator signal to generate a required radio frequency chaotic signal;
the frequency source is used for providing a working clock of the FPGA, providing an intermediate frequency local oscillation signal to the IQ modulator, and providing a radio frequency local oscillation signal to the transmitting up-conversion module.
As an improvement of the above system, the baseband IQ path waveform generation module includes: the device comprises a chaotic sequence generator, a band-pass filter, two frequency converters and two low-pass filters; the two frequency converters are connected in parallel, and each frequency converter is connected with one low-pass filter in series;
the chaotic sequence generator is used for generating a chaotic sequence and inputting the chaotic sequence into the band-pass filter;
the band-pass filter is used for performing band-pass filtering processing on the chaotic sequence to obtain a band-limited chaotic sequence and inputting the band-limited chaotic sequence into the two frequency converters at the same time;
the two frequency converters are used for carrying out digital down-conversion on the band-limited chaotic sequence to obtain two paths of orthogonal baseband chaotic signals and respectively inputting the two paths of orthogonal baseband chaotic signals into low-pass filters which are respectively connected in series;
the two low-pass filters are used for respectively performing low-pass filtering processing on the two paths of orthogonal baseband chaotic signals to obtain baseband I path waveform data and baseband Q path waveform data of the chaotic radar.
As an improvement of the above system, the chaotic sequence is:
x(n+1)＝k·x(n)·(1-x(n))
wherein x (N) represents a current value of the Logistic chaotic signal mapping, x (N +1) represents a next iteration value of the Logistic chaotic signal mapping, k is a parameter of the Logistic chaotic signal mapping, N is a sequence number of the Logistic chaotic signal mapping sequence, and N is 0,1,2, …, NP-1，NPThe Logistic chaotic sequence length corresponding to each transmitted pulse is as follows:
NP＝TP·Fsr
wherein, TPFor transmitting pulse signal duration, FsrIs the sampling rate of the DAC module.
As an improvement of the above system, the band-limited chaotic sequence xB(n) is:
wherein h isB(k) Is the band-pass filter coefficient, K is 0,1,2, …, K-1, K is the band-pass filter order, hB(k) According to the pass band range of the band-pass filter 0.5-Br/Fsr,0.5+Br/Fsr]Is calculated to obtainrIs the bandwidth of the chaotic waveform emitted by the radar.
As an improvement of the above system, the two orthogonal baseband chaotic signals are:
wherein f is0Intermediate frequency local oscillator signals for mixing, f0＝Fsr/4。
As an improvement of the above system, the baseband I path waveform data and the baseband Q path waveform data of the chaotic radar are:
wherein the filter isNumber hL(M), M is 0,1,2, …, M-1, M is the order of the low pass filter, hL(m) a passband bandwidth of [0, B ] according to the low pass filterr/Fsr]And (4) calculating.
A chaos radar transmitting signal real-time generating method based on FPGA is realized based on the system, and the method comprises the following steps:
the baseband IQ path waveform generation module respectively generates baseband I path waveform data and baseband Q path waveform data of the chaotic radar and inputs the baseband I path waveform data and the baseband Q path waveform data into the DAC module;
the DAC module respectively carries out digital-to-analog conversion on the baseband I path waveform data and the baseband Q path waveform data to obtain a baseband I path analog waveform and a baseband Q path analog waveform, and inputs the baseband I path analog waveform and the baseband Q path analog waveform into the IQ modulator;
the IQ modulator is used for carrying out IQ modulation on the baseband I path analog waveform and the baseband Q path analog waveform in combination with the intermediate frequency local oscillator signal, generating an intermediate frequency chaotic signal and inputting the intermediate frequency chaotic signal into the transmitting up-conversion module;
the transmitting up-conversion module mixes the intermediate frequency chaotic signal and the radio frequency local oscillator signal to generate a required radio frequency chaotic signal;
the working clock of the baseband IQ path waveform generation module, the intermediate frequency local oscillator signal and the radio frequency local oscillator signal are all provided by a frequency source.
Compared with the prior art, the invention has the advantages that:
1. the chaos radar transmitting signals are generated through real-time calculation based on the FPGA, the waveform of each pulse is a pseudo-random signal similar to noise, the transmitting waveforms of the pulses are different, the transmitting waveforms are noise signals for enemies, and are difficult to intercept and decipher, so that the low detection probability characteristic, the low interception probability characteristic and the electronic anti-interference capability of the radar can be effectively improved;
2. the chaos radar transmitting signal is generated based on FPGA real-time calculation, the transmitted waveform is a pseudo-random signal generated by a deterministic system, the own radar signal processor is a deterministic waveform, the transmitted pseudo-random chaotic signal can be reconstructed by using a chaotic model, the radar echo signal is very conveniently subjected to pulse compression processing, the transmitted signal of each pulse does not need to be acquired back through a delay line for calibration in a random noise simulation generation mode, and one-path data acquisition can be reduced;
3. the system uses a general FPGA, a general DAC and an IQ modulator, has high portability and is convenient to transplant into other radar systems.
Drawings
Fig. 1 is a block diagram of a system for generating a chaos radar transmission signal in real time based on an FPGA according to embodiment 1 of the present invention;
fig. 2 is a flow chart of the baseband IQ path waveform generation module to generate a chaos radar transmission signal in real time according to embodiment 1 of the present invention;
fig. 3 is a block diagram of a state machine for generating a Logistic chaotic sequence by a baseband IQ path waveform generation module according to embodiment 1 of the present invention;
fig. 4(a) is a waveform diagram of the baseband I of the chaotic radar generated by the baseband IQ waveform generation module in embodiment 1 of the present invention;
fig. 4(b) is a waveform diagram of a baseband Q path of the chaotic radar generated by the baseband IQ path waveform generating module in embodiment 1 of the present invention;
fig. 5(a) is a waveform diagram of a baseband I path of a chaos radar sampled by a DAC module in embodiment 1 of the present invention;
fig. 5(b) is a waveform diagram of a baseband Q path of the chaotic radar sampled by the DAC module in embodiment 1 of the present invention;
fig. 6 is a diagram showing the result of pulse compression of the baseband echo waveform sampled by the DAC module by the signal processor reconstructing the transmit waveform according to embodiment 1 of the present invention.
Detailed Description
The invention aims to generate chaotic radar transmitting signals in real time based on an FPGA (field programmable gate array), wherein the waveform of each transmitting pulse is a pseudo-random chaotic signal similar to noise, and the transmitting waveforms of all the pulses are different. The emitted waveform is a noise signal for the enemy, is difficult to intercept and decipher, and can effectively improve the low interception probability characteristic and the electronic anti-interference capability of the radar. Meanwhile, the transmitted Waveform is a pseudo-random Signal generated by a deterministic chaotic model, and for the deterministic Waveform of the own party, the transmitted pseudo-random chaotic Signal can be reconstructed by using the chaotic model in a Signal processor of the own party, so that the pulse compression Processing can be conveniently carried out on the Radar echo Signal, and the transmitted Signal of each pulse is not required to be acquired back through a delay line for calibration in a random Noise simulation generation mode (reference [2 ]: Krzysztoff Kulpa, Signal Processing in Noise wave Radar, ISBN: 9781608076611), so that one-path data acquisition of a Radar system can be reduced.
The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and examples.
Example 1
the baseband IQ path waveform generation module is realized by an FPGA and is used for respectively generating baseband I path waveform data and baseband Q path waveform data of the chaotic radar and inputting the baseband I path waveform data and the baseband Q path waveform data into the DAC module;
the baseband IQ path waveform generation module comprises: the device comprises a chaotic sequence generator, a band-pass filter, two frequency converters and two low-pass filters; the two frequency converters are connected in parallel, and each frequency converter is connected with one low-pass filter in series;
the chaotic sequence generator is used for generating a chaotic sequence and inputting the chaotic sequence into the band-pass filter;
the band-pass filter is used for performing band-pass filtering processing on the chaotic sequence to obtain a band-limited chaotic sequence and inputting the band-limited chaotic sequence into the two frequency converters at the same time;
the two frequency converters are used for carrying out digital down-conversion on the band-limited chaotic sequence to obtain two paths of orthogonal baseband chaotic signals and respectively inputting the two paths of orthogonal baseband chaotic signals into low-pass filters which are respectively connected in series;
the two low-pass filters are used for respectively performing low-pass filtering processing on the two paths of orthogonal baseband chaotic signals to obtain baseband I path waveform data and baseband Q path waveform data of the chaotic radar.
The DAC module is used for respectively carrying out digital-to-analog conversion on the baseband I path waveform data and the baseband Q path waveform data to obtain a baseband I path analog waveform and a baseband Q path analog waveform, and inputting the baseband I path analog waveform and the baseband Q path analog waveform into the IQ modulator;
the IQ modulator is used for carrying out IQ modulation on the baseband I path analog waveform and the baseband Q path analog waveform in combination with the intermediate frequency local oscillator signal, generating an intermediate frequency chaotic signal and inputting the intermediate frequency chaotic signal into the transmitting up-conversion module;
the transmitting up-conversion module is used for mixing the intermediate frequency chaotic signal and the radio frequency local oscillator signal to generate a required radio frequency chaotic signal;
and the frequency source is used for providing a working clock of the FPGA, providing an intermediate frequency local oscillation signal to the IQ modulator and providing a radio frequency local oscillation signal to the transmitting up-conversion module.
It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is provided solely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
In this embodiment, the duration T of the signal transmitted by the radar systemP10us, bandwidth Br100MHz, DAC chip sampling rate of Fsr2500 Msps. A flow chart of a method for generating a chaos radar transmitting signal in real time in an FPGA by a baseband IQ path waveform generation module is shown in fig. 2.
Optionally, the method for generating the chaos radar transmitting signal in real time based on the FPGA in the above technical scheme further includes:
step 101) generating a chaotic sequence in the FPGA by using a state machine.
In this embodiment, taking a Logistic chaotic signal as an example, the generated chaotic sequence expression is as follows:
x(n+1)＝k·x(n)·(1-x(n)) (1)
wherein, x (n) represents the current value of the Logistic mapping, x (n +1) represents the next iteration value of the Logistic mapping, k is the parameter of the Logistic mapping, and n is the sequence number of the Logistic mapping.
In general, the input and output of the Logistic map are distributed between (0,1), and the decimal on (0,1) is first written into binary in the FPGA, and the expression is as follows:
wherein, ciIs a binary 0 or 1.
Taking the first L bits to represent, then:
wherein the content of the first and second substances,
is an integer represented by an L-bit binary, and the decimal x (n) corresponds to one. Writing x (n +1) and x (n) to the above form, one can obtain:
X(n+1)＝k·X(n)·(2L-1-X(n))·2-(L-1) (4)
wherein, X (0) ═ round (2)L-1X (0)), round denotes rounding the variable. X (0) is an initial value of the Logistic chaotic sequence and can be injected into the FPGA from the outside through interfaces such as a serial port or a network port. In this embodiment, setting k to 0.875 may be regarded as: k is 1-0.125. The shift can be realized in FPGA, 0.125 is 3bit shift to the right.
The above equation (4) is implemented in the FPGA as a state machine, and 4 states are required for generating one Logistic chaotic sequence value, as shown in fig. 3.
According to the duration T of the transmitted pulse signalPAnd the sampling rate F of the DACsrCalculating to obtain the length of the Logistic chaotic sequence required by each transmitted pulse signal as follows:
NP＝TP·Fsr (5)
that is, the formula N is 0,1,2, …, NP-1. In this embodiment, NP＝25000。
Step 102) performing band-limited filtering processing on the generated chaotic sequence x (n), further comprising:
step 102-1) setting the pass band range of the band-pass filter to be 0.5-Br/Fsr,0.5+Br/Fsr]The order of the filter is K, meterCalculating to obtain filter coefficient hB(k)，k＝0,1,2,…,K-1。BrIs the bandwidth of the chaotic waveform emitted by the radar.
102-2) performing band-pass filtering processing on the pseudo-random chaotic sequence x (n) to obtain a band-limited chaotic sequence xB(n) is as follows:
in this embodiment, the pass band of the band pass filter is [0.42,0.58 ]]. Setting the order K of the band-pass filter to 31, and calculating to obtain the coefficient h of the band-limit filterB(k) Then, the bandpass filtering processing of the pseudo-random chaotic sequence x (n) is realized in the FPGA by using an IP core expression (6).
Step 103) for xB(n) carrying out digital down-conversion treatment to obtain sequences corresponding to the two paths of I/Q, as shown in the following formula.
A simple design approach is proposed using parameters in engineering applications. Using intermediate frequency signals f0＝F sr4, the parameters are chosen such that c o (s π 2 f)0n/Fsr) The value of the signal in one period is {0, -1,0,1}, -sin (2 π f }0n/Fsr) The value of the signal is {1,0,0, -1 }. The method is realized in FPGA, and the numerical values {1,0, -1} respectively correspond to the operations of invariance, zero setting and negation.
Step 104) performing a low pass filtering process on i (n) and q (n), further comprising:
step 104-1) setting the passband bandwidth of the low-pass filter to be 0, Br/Fsr]The order of the filter is M, and the filter coefficient h is obtained by calculationL(m)，m＝0,1,2，…，M-1。
Step 104-2) low-pass filtering the I (n) and the Q (n) to obtain a sequence IL(n) and QL(n) is as follows:
in this embodiment, the low pass filter has a passband of [0,0.08 ]]The order M is 31, and the low-pass filter coefficient h is obtained by calculationL(m) of the reaction mixture. The low pass filtering process of I (n) and Q (n) of equation (8) is realized in the FPGA using IP core. The paths I and Q and the frequency spectrum of the baseband transmission waveform obtained through the steps are shown in the attached figures 4(a) and (b).
And 105) the FPGA simultaneously outputs the waveforms of the I path and the Q path of the baseband transmission to the DAC chip according to the working time sequence of the radar system.
In an actual radar system, the I-path waveform and the Q-path waveform output by the DAC are sampled by using the ADC with the sampling rate of 250Msps, and the obtained waveforms are shown in fig. 5(a) and (b). The signal processor reconstructs a transmitting signal by using the chaotic model, and pulse compression processing is performed on the waveform sampled by the ADC, and the obtained result is shown in figure 6, so that the pulse compression effect is good.
It should be noted that, in this embodiment, a pseudo-random waveform is generated by taking Logistic mapping as an example, and the system can be used for chaotic waveforms of different algorithms, but the algorithm for waveform formation is different.
Example 2
Based on the system of embodiment 1, embodiment 2 of the present application provides a chaos radar transmitting signal real-time generating method based on an FPGA, which specifically includes the following steps:
the FPGA generates waveform data of an I path and a Q path of the chaotic radar baseband and simultaneously transmits the waveform data to 2 DAC chips;
the 2-path DAC chip respectively performs digital-to-analog conversion on the I-path waveform data and the Q-path waveform data to generate baseband I-path analog waveforms and baseband Q-path analog waveforms, and the baseband I-path analog waveforms and the baseband Q-path analog waveforms are transmitted to an IQ modulator;
the IQ modulator performs IQ modulation on input analog waveforms of the path I and the path Q in combination with an intermediate-frequency local oscillator signal LO2 to generate an intermediate-frequency chaotic signal, and the intermediate-frequency chaotic signal is transmitted to the transmitting up-conversion module;
the transmitting up-conversion module mixes the intermediate frequency chaotic signal with a radio frequency local oscillator LO1 to generate a required radio frequency chaotic signal.
The frequency source provides an operating clock of the FPGA, an intermediate frequency local oscillator LO2 used by the IQ modulator, and a radio frequency local oscillator LO1 used for transmitting up-conversion.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (7)
1. A chaos radar transmitting signal real-time generating system based on FPGA is characterized in that the system comprises: the device comprises a baseband IQ path waveform generation module, a DAC module, an IQ modulator, a transmitting up-conversion module and a frequency source; wherein the content of the first and second substances,
the baseband IQ path waveform generation module is realized by an FPGA and is used for respectively generating baseband I path waveform data and baseband Q path waveform data of the chaotic radar and inputting the baseband I path waveform data and the baseband Q path waveform data into the DAC module;
the DAC module is used for respectively carrying out digital-to-analog conversion on the baseband I path waveform data and the baseband Q path waveform data to obtain a baseband I path analog waveform and a baseband Q path analog waveform, and inputting the baseband I path analog waveform and the baseband Q path analog waveform into the IQ modulator;
the IQ modulator is used for carrying out IQ modulation on the baseband I path analog waveform and the baseband Q path analog waveform in combination with the intermediate frequency local oscillator signal, generating an intermediate frequency chaotic signal and inputting the intermediate frequency chaotic signal into the transmitting up-conversion module;
the transmitting up-conversion module is used for mixing the intermediate frequency chaotic signal and the radio frequency local oscillator signal to generate a required radio frequency chaotic signal;
the frequency source is used for providing a working clock of the FPGA, providing an intermediate frequency local oscillation signal to the IQ modulator, and providing a radio frequency local oscillation signal to the transmitting up-conversion module.
2. The FPGA-based chaotic radar transmit signal real-time generation system of claim 1, wherein the baseband IQ path waveform generation module comprises: the device comprises a chaotic sequence generator, a band-pass filter, two frequency converters and two low-pass filters; the two frequency converters are connected in parallel, and each frequency converter is connected with one low-pass filter in series;
the chaotic sequence generator is used for generating a chaotic sequence and inputting the chaotic sequence into the band-pass filter;
the band-pass filter is used for performing band-pass filtering processing on the chaotic sequence to obtain a band-limited chaotic sequence and inputting the band-limited chaotic sequence into the two frequency converters at the same time;
the two frequency converters are used for carrying out digital down-conversion on the band-limited chaotic sequence to obtain two paths of orthogonal baseband chaotic signals and respectively inputting the two paths of orthogonal baseband chaotic signals into low-pass filters which are respectively connected in series;
the two low-pass filters are used for respectively performing low-pass filtering processing on the two paths of orthogonal baseband chaotic signals to obtain baseband I path waveform data and baseband Q path waveform data of the chaotic radar.
3. The chaotic radar transmission signal real-time generation system based on the FPGA of claim 2, wherein the chaotic sequence is:
x(n+1)＝k·x(n)·(1-x(n))
wherein x (N) represents a current value of the Logistic chaotic signal mapping, x (N +1) represents a next iteration value of the Logistic chaotic signal mapping, k is a parameter of the Logistic chaotic signal mapping, N is a sequence number of the Logistic chaotic signal mapping sequence, and N is 0,1,2, …, NP-1，NPThe Logistic chaotic sequence length corresponding to each transmitted pulse is as follows:
NP＝TP·Fsr
wherein, TPFor transmitting pulse signal duration, FsrIs the sampling rate of the DAC module.
4. The FPGA-based chaotic radar transmit signal real-time generation system of claim 3, wherein the band-limited chaotic sequence xB(n) is:
wherein h isB(k) Is the band-pass filter coefficient, K is 0,1,2, …, K-1, K is the band-pass filter order, hB(k) According to the pass band range of the band-pass filter 0.5-Br/Fsr,0.5+Br/Fsr]Is calculated to obtainrIs the bandwidth of the chaotic waveform emitted by the radar.
5. The FPGA-based pseudo-random chaotic signal real-time generation system of claim 4, wherein the two orthogonal baseband chaotic signals are:
wherein f is0Intermediate frequency local oscillator signals for mixing, f0＝Fsr/4。
6. The FPGA-based chaotic radar transmit signal real-time generation system of claim 5, wherein the baseband I path waveform data and the baseband Q path waveform data of the chaotic radar are:
wherein the filter coefficient hL(M), M is 0,1,2, …, M-1, M is the order of the low pass filter, hL(m) a passband bandwidth of [0, B ] according to the low pass filterr/Fsr]And (4) calculating.
7. A chaos radar transmitting signal real-time generating method based on FPGA, which is realized based on the system of one of claims 1-6, the method comprising:
the baseband IQ path waveform generation module respectively generates baseband I path waveform data and baseband Q path waveform data of the chaotic radar and inputs the baseband I path waveform data and the baseband Q path waveform data into the DAC module;
the DAC module respectively carries out digital-to-analog conversion on the baseband I path waveform data and the baseband Q path waveform data to obtain a baseband I path analog waveform and a baseband Q path analog waveform, and inputs the baseband I path analog waveform and the baseband Q path analog waveform into the IQ modulator;
the IQ modulator is used for carrying out IQ modulation on the baseband I path analog waveform and the baseband Q path analog waveform in combination with the intermediate frequency local oscillator signal, generating an intermediate frequency chaotic signal and inputting the intermediate frequency chaotic signal into the transmitting up-conversion module;
the transmitting up-conversion module mixes the intermediate frequency chaotic signal and the radio frequency local oscillator signal to generate a required radio frequency chaotic signal;
the working clock of the baseband IQ path waveform generation module, the intermediate frequency local oscillator signal and the radio frequency local oscillator signal are all provided by a frequency source.
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