A multi-target signal synthesis method supporting loop playback

Abstract

The present invention belongs to the field of signal processing technology, and discloses a multi-target signal synthesis method supporting loop playback, including parsing signal parameters, processing the center frequency of multiple signals, extracting the periodic parameters that need to be processed from each signal according to its modulation type, calculating the optimal signal sampling point number ram under the sampling rate and maximum ram requirements, independently generating N signals according to the obtained sampling point number and the adjusted parameter value, loading the baseband frequency shift, amplitude and phase information of each signal, and directly superimposing multiple signals in the time domain to obtain the final baseband synthesis signal. The method proposed by the present invention performs periodic control on multiple signals and synthesizes the final signal, does not limit the number, type, parameters, etc. of signals, is implemented through software, and reduces the consumption of hardware resources.

Description

Technical Field

[0001] The present invention relates to the technical field of signal processing, and more specifically to a multi-target signal synthesis method supporting loop playback. Background Art

[0002] Signal generation is widely used in complex electromagnetic environment construction, dynamic and static target simulation, etc. Conventional signal generation mainly focuses on the modulation parameters of the signal, but when it comes to the scenario of looping the signal waveform, the periodicity of the signal is very high. If there is a breakpoint at the end of the waveform, the quality of the transmitted signal will be seriously affected.

[0003] Generally, the periodicity of a single signal is relatively easy to control due to its simple parameters, but the difficulty of periodicity control is greatly increased in the case of multiple signals. The existing solutions include: independently generating multiple periodic single signals, and using hardware to loop the waveform files separately and then synthesize the final signal file for playback, but this method consumes a certain amount of hardware resources and has low processing efficiency. Summary of the invention

[0004] Aiming at the scenario where multiple signals with different frequencies, amplitudes, phases, modulation types and parameters need to be output simultaneously, the present invention proposes a multi-target signal synthesis method supporting loop playback.

[0005] The present invention provides a multi-target signal synthesis method supporting loop playback, which adopts the following technical solution:

[0006] A multi-target signal synthesis method supporting loop playback, the method comprising the following steps:

[0007] S1. Analyze signal parameters, process the center frequencies of multiple signals, and extract the periodic parameters that need to be processed from each signal according to its modulation type;

[0008] S2, calculating the optimal signal waveform sampling point number ram under the sampling rate and the maximum allowed signal waveform sampling point number requirement;

[0009] S3, independently generating N signals according to the obtained number of sampling points and the adjusted parameter values;

[0010] S4, loading the baseband frequency shift, amplitude and phase information of each signal;

[0011] S5. Multiple signals are directly superimposed in the time domain to obtain the final baseband composite signal.

[0012] Furthermore, analyzing the signal parameters in S1 includes the following steps:

[0013] S101, obtaining signal configuration parameters;

[0014] S102, processing center frequency and baseband frequency shift;

[0015] S103, signal number sigIdx=0, extracting the periodic parameters of the current signal;

[0016] S104, the signal number sigIdx is incremented by 1;

[0017] S105. If the signal number sigIdx≥N, end; if the signal number sigIdx<N, return to S104.

[0018] Further, the calculation of the optimal number of signal sampling points ram in S2 includes the following steps:

[0019] S201, obtaining the periodic parameters, fs, and ram maximum value ramMax of each signal;

[0020] S202, calculating the minimum signal parameter adjustment error rms value ramMin statistically during the cycle according to at least 10 cycles;

[0021] S203, ram=ramMin, rmsMin=1000;

[0022] S204, while1;

[0023] S205, signal number sigIdx=0;

[0024] S206, periodic parameter index i=0;

[0025] S207, extracting the periodic parameter fi to be processed currently;

[0026] S208, calculating the integer multiple period and adjusted fi under the current ram and fs;

[0027] S209, calculating the adjustment error of the parameter fi;

[0028] S210, i is incremented by 1;

[0029] S211, if i≥the number of parameters of the current signal, calculate the rms value rms_sigIdx of the adjustment error of all parameters of the current signal; if i<the number of parameters of the current signal, return to S207;

[0030] S212, signal number sigIdx is incremented by 1;

[0031] S213, if the signal number sigIdx≥N, calculate the adjustment error rms value rmsTotal of all signals, if sigIdx<N, return to S206;

[0032] S214, if rmsTotal≤rmsMin, update rmsMin and the corresponding ram and rmsTotal values; if rmsTotal<rmsMin, proceed to the next step;

[0033] S215, if the value of rmsTotal is equal to 0, record the current ram and rmsTotal values, exit while, if the value of rmsTotal is not equal to 0, determine whether ram ≥ ramMax, if so, exit while, if not, ram is accumulated by 1, and return to S205;

[0034] S216. If the recorded rms value is equal to 0, the input periodic parameters and ram are output; if the rms value is not equal to 0, all periodic parameters under the current ram and fs are calculated, and new periodic parameters and ram are output.

[0035] Furthermore, the calculation formula of the adjustment error includes:

[0036] a. Adjustment error of the i-th frequency parameter under the sigIdx-th signal:

[0037]

[0038] b. The rms value of the adjustment error of the sigIdx-th signal:

[0039]

[0040] c. The adjustment error rms value of all signals under the current RAM:

[0041]

[0042] Among them, M sigIdx Refers to the number of periodic parameters of the sigIdx-th signal, and N refers to the number of signals.

[0043] In summary, the present invention includes at least one of the following beneficial technical effects:

[0044] The method proposed in the present invention is used to process the periodicity of multi-target signals to perform loop playback of signal files without breakpoints. For the common problem of breakpoints when multiple signals are directly added and then played in a loop, the method controls the parameters related to the periodicity of each signal and performs fine-tuning to meet the periodicity of each signal under the current parameter configuration, and then synthesizes the signals and plays them in a loop. There is no limit on the number, type, parameters, etc. of signals. It is implemented through software, reducing the consumption of hardware resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a multi-signal synthesis flow chart of the present invention;

[0046] Figure 2 Flowchart for analyzing signal parameters;

[0047] Figure 3 is a flow chart of periodic parameter processing;

[0048] Figure 4 It is the time domain head-to-tail splicing diagram of the synthetic signal when there is no error in the periodic parameters;

[0049] Figure 5 The spectrum diagram of the synthetic signal when there is no error in the periodic parameters;

[0050] Figure 6 This is the time domain head-to-tail splicing diagram of the synthetic signal when there is an error in the periodic parameter;

[0051] Figure 7 This is the spectrum diagram of the synthetic signal when there is an error in the periodic parameter. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0053] Embodiment 1:

[0054] The embodiment of the present invention discloses a multi-target signal synthesis method supporting loop playback, the method comprising the following steps:

[0055] S1. Analyze signal parameters, process the center frequency of multiple signals, and extract the periodic parameters that need to be processed from each signal according to its modulation type, such as Figure 2 As shown, parsing signal parameters includes the following steps:

[0056] S101, obtaining signal configuration parameters;

[0057] S102, processing center frequency and baseband frequency shift;

[0058] S103, signal number sigIdx=0, extracting the periodic parameters of the current signal;

[0059] S104, the signal number sigIdx is incremented by 1;

[0060] S105. If the signal number sigIdx≥N, end; if the signal number sigIdx<N, return to S104.

[0061] S2. Calculate the optimal signal waveform sampling point number ram under the sampling rate and the maximum allowed signal waveform sampling point number requirements, such as Figure 3 As shown, the core purpose is to calculate the number of sampling points RAM with the minimum adjustment error under the limitation of the maximum RAM. Specifically, it includes the following steps:

[0062] S201, obtaining the periodic parameters, fs, and ram maximum value ramMax of each signal;

[0063] S202, calculating the minimum signal parameter adjustment error rms value ramMin statistically during the cycle according to at least 10 cycles;

[0064] S203, ram=ramMin, rmsMin=1000;

[0065] S204, while1;

[0066] S205, signal number sigIdx=0;

[0067] S206, periodic parameter index i=0;

[0068] S207, extracting the periodic parameter fi to be processed currently;

[0069] S208, calculating the integer multiple period and adjusted fi under the current ram and fs;

[0070] S209, calculating the adjustment error of the parameter fi;

[0071] S210, i is incremented by 1;

[0072] S211, if i≥the number of parameters of the current signal, calculate the rms value rms_sigIdx of the adjustment error of all parameters of the current signal; if i<the number of parameters of the current signal, return to S207;

[0073] S212, signal number sigIdx is incremented by 1;

[0074] S213, if the signal number sigIdx≥N, calculate the adjustment error rms value rmsTotal of all signals, if sigIdx<N, return to S206;

[0075] S214, if rmsTotal≤rmsMin, update rmsMin and the corresponding ram and rmsTotal values; if rmsTotal<rmsMin, proceed to the next step;

[0076] S215, if the value of rmsTotal is equal to 0, record the current ram and rmsTotal values, exit while, if the value of rmsTotal is not equal to 0, determine whether ram ≥ ramMax, if so, exit while, if not, ram is accumulated by 1, and return to S205;

[0077] S216. If the recorded rms value is equal to 0, the input periodic parameters and ram are output; if the rms value is not equal to 0, all periodic parameters under the current ram and fs are calculated, and new periodic parameters and ram are output.

[0078] Accordingly, the above adjustment error calculation formulas are:

[0079] a. Adjustment error of the i-th frequency parameter under the sigIdx-th signal:

[0080]

[0081] b. The rms value of the adjustment error of the sigIdx-th signal:

[0082]

[0083] c. The adjustment error rms value of all signals under the current RAM:

[0084]

[0085] Among them, M sigIdx Refers to the number of periodic parameters of the sigIdx-th signal, and N refers to the number of signals.

[0086] S3. Generate N signals independently according to the obtained number of sampling points and the adjusted parameter values.

[0087] S4. Load each signal with its baseband frequency shift, amplitude and phase information.

[0088] S5. Multiple signals are directly superimposed in the time domain to obtain the final baseband composite signal.

[0089] It should be noted that S3, S4, and S5 in the above steps are conventional means in signal processing, which are not the main content of this method and will not be described in detail in this article. In addition, the process of this method generates the baseband part of the synthesized signal. If a radio frequency signal with a carrier needs to be generated, Figure 2 The center frequency obtained in Figure 3 In the process, it is used as a periodic parameter for processing, and the final baseband synthesis signal is up-converted.

[0090] The basic principle of the multi-target signal synthesis method supporting loop playback of the present invention is:

[0091] To control the periodicity of a signal, assume that one of the periodic parameters of a signal is f i ; The required sampling rate is f s ; The number of sampling points to generate the signal is ram, then the following formula is available:

[0092]

[0093] Among them, nPrd refers to the number of cycles under the current parameters. i In the case where nPrd is not an integer, then for f i The parameter signal is non-periodic. If it is rounded to an integer number of periods, then f i becomes f' i :

[0094] nPrdInt = round(nPrd)

[0095]

[0096] At this time, the periodic parameter f i The relative error of adjustment is:

[0097]

[0098] The above is a basic unit for controlling a single periodic parameter. The method proposed in the present invention is to adjust the RAM for different signals and different periodic parameters to obtain the rms (err i ) to obtain the minimum value of the optimal RAM and adjusted parameter values. i )The calculation formula is shown above.

[0099] In addition, this method does not limit the number, type, and parameters of signals. This section analyzes the periodic parameters of common signals for illustration only, and other signals not proposed can be deduced by analogy.

[0100] 1. Public parameters:

[0101] In the multi-signal synthesis scenario, the frequency domains of the signals are generally non-overlapping, so each signal has its own carrier frequency. In the process of generating signals, the carrier frequencies of multiple signals are divided into a unified center frequency + baseband frequency offset of each signal. The specific processing is as follows:

[0102] Assume that N signals are synthesized, and the center frequency of each signal is f i , bandwidth is B i .

[0103] (1) Calculate the left and right edge frequencies of the bandwidth of each signal:

[0104]

[0105] (2) Calculate the leftmost frequency f respectively left and the rightmost frequency f right :

[0106]

[0107] (3) Calculate the unified center frequency f c and the baseband frequency offset f of each signal mi :

[0108]

[0109] f mi =f i -f c

[0110] 2. Digital modulation signal:

[0111] Conventional digital signals are divided into two categories: one is amplitude-phase modulation signals, and the other is frequency modulation signals. For amplitude-phase modulation signals (such as MPSK, MQAM, MAPSK, STAR, etc.), the periodic parameters are symbol rate; for frequency modulation signals (such as MFSK, MSK, etc.), the periodic parameters are symbol rate and modulation frequency deviation. Since the above parameters are all frequency-related parameters, no special processing is required.

[0112] 3. Analog modulation signal:

[0113] For AM, FM, and PM: AM periodic modulation parameters are modulation frequency; FM periodic modulation parameters are modulation frequency and modulation frequency deviation; PM periodic modulation parameters are modulation frequency and modulation phase deviation. The modulation phase deviation parameter needs to be processed as follows to convert to frequency units:

[0114] For single frequency modulated FM and PM signals, assuming that the FM modulation frequency and modulation frequency deviation are f c and f m , PM modulation frequency and modulation phase deviation are f c and p m , the sampling rate is f s .

[0115] The modulated signal is:

[0116]

[0117] The baseband FM signal is:

[0118]

[0119] The baseband PM signal is:

[0120]

[0121] Where n = 0, 1, ..., ram-1, ram is the number of signal sampling points; cumsum(·) means accumulating the signal.

[0122] Therefore, the following comparison is made:

[0123]

[0124] Then the frequency parameter corresponding to the modulation phase deviation under PM modulation can be obtained:

[0125]

[0126] 4. Radar signal:

[0127] (1) Radar signal with fixed pulse repetition interval PRI:

[0128] PRI is the period of the signal, and its frequency parameter is the repetition rate PRF = 1 / PRI.

[0129] (2) Radar signal with varying pulse repetition interval PRI:

[0130] Multiple PRIs and is the period of the signal: PRI total =∑PRI i , its frequency parameter is 1 / PRI total .

[0131] 5. Frequency Hopping Signal:

[0132] The hopping rate of the frequency hopping signal is a periodic frequency parameter, similar to the PRF of a radar signal.

[0133] 6. Spread spectrum signal:

[0134] Assume that the chip rate of the signal is f chip , the spreading factor is β, and the periodic frequency parameter is its symbol rate:

[0135]

[0136] 7.Multi-tone signal:

[0137] The frequency set of the multi-tone signal is its periodic frequency parameter. Given that a unified center frequency f is obtained in the common parameters c , for a multi-tone signal, each tone of its baseband signal has its own frequency, and loop playback requires that each tone is periodic. Convert the frequency of each tone into the baseband signal frequency deviation:

[0138]

[0139] in, is the frequency of the required multi-tone, is the baseband signal frequency deviation.

[0140] Simulation Example

[0141] The following is a simulation example of the method provided by the present invention, and the simulation parameters are shown in the following table:

[0142]

[0143] Simulation 1: ramMax = 1e9

[0144] Under the current limitation, the best RAM value is 6300000, at which the RMS error is 0 and there is no adjustment error in the periodic parameters. The synthesized baseband signal in the time domain and frequency domain is as follows: Figure 4 and Figure 5 shown.

[0145] Simulation 2: ramMax = 6e6

[0146] Under the current limitation, the best RAM value is 5499975, and the RMS error is 5.693e-06. The synthesized baseband signal in time domain and frequency domain is as follows Figure 6 and Figure 7 shown.

[0147] From the simulation, it can be seen that there are no breakpoints in the time domain head-to-tail connection both in the case of no error and with error, which ensures the continuity of the signal loop playback.

[0148] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-target signal synthesis method supporting loop playback, characterized in that: The method comprises the following steps: S1. Analyze signal parameters, process the center frequencies of multiple signals, and extract the periodic parameters that need to be processed from each signal according to its modulation type; S2, calculating the optimal signal waveform sampling point number ram under the sampling rate and the maximum allowed signal waveform sampling point number requirement; S3, independently generating N signals according to the obtained number of sampling points and the adjusted parameter values; S4, loading the baseband frequency shift, amplitude and phase information of each signal; S5. Multiple signals are directly superimposed in the time domain to obtain the final baseband composite signal.

2. A multi-target signal synthesis method supporting loop playback according to claim 1, characterized in that: The analysis of signal parameters in S1 comprises the following steps: S101, obtaining signal configuration parameters; S102, processing center frequency and baseband frequency shift; S103, signal number sigIdx=0, extracting the periodic parameters of the current signal; S104, the signal number sigIdx is incremented by 1; S105. If the signal number sigIdx≥N, end; if the signal number sigIdx<N, return to S104.

3. The method for synthesizing multi-target signals supporting loop playback according to claim 1, characterized in that: Calculating the optimal signal sampling point number ram in S2 comprises the following steps: S201, obtaining the periodic parameters, fs, and ram maximum value ramMax of each signal; S202, calculating the minimum signal parameter adjustment error rms value ramMin statistically during the cycle according to at least 10 cycles; S203, ram=ramMin, rmsMin=1000; S204, while1; S205, signal number sigIdx=0; S206, periodic parameter index i=0; S207, extracting the periodic parameter fi to be processed currently; S208, calculating the integer multiple period and adjusted fi under the current ram and fs; S209, calculating the adjustment error of the parameter fi; S210, i is incremented by 1; S211, if i≥the number of parameters of the current signal, calculate the rms value rms_sigIdx of the adjustment error of all parameters of the current signal; if i<the number of parameters of the current signal, return to S207; S212, signal number sigIdx is incremented by 1; S213, if the signal number sigIdx≥N, calculate the adjustment error rms value rmsTotal of all signals, if sigIdx<N, return to S206; S214, if rmsTotal≤rmsMin, update rmsMin and the corresponding ram and rmsTotal values; if rmsTotal<rmsMin, proceed to the next step; S215, if the value of rmsTotal is equal to 0, record the current ram and rmsTotal values, exit while, if the value of rmsTotal is not equal to 0, determine whether ram ≥ ramMax, if so, exit while, if not, ram is accumulated by 1, and return to S205; S216. If the recorded rms value is equal to 0, the input periodic parameters and ram are output; if the rms value is not equal to 0, all periodic parameters under the current ram and fs are calculated, and new periodic parameters and ram are output.

4. The method for synthesizing multi-target signals supporting loop playback according to claim 3, characterized in that: The calculation formula of the adjustment error includes: a. Adjustment error of the i-th frequency parameter under the sigIdx-th signal: b. The rms value of the adjustment error of the sigIdx-th signal: c. The adjustment error rms value of all signals under the current RAM: Among them, M sigIdx Refers to the number of periodic parameters of the sigIdx-th signal, and N refers to the number of signals.

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