Frequency extraction method of frequency diversity signal
A technology of frequency diversity and frequency extraction, applied in the direction of frequency diversity, diversity/multi-antenna systems, etc., can solve the problems of low accuracy in determining the number of signal frequencies and high signal-to-noise ratio requirements
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specific Embodiment approach 1
[0016] A frequency extraction method of a frequency diversity signal according to this embodiment, the method includes a frequency number determination part and a real frequency calculation part, specifically implemented through the following steps:
[0017] Step 1, acquiring a signal, and performing frequency conversion and filtering preprocessing on the acquired signal;
[0018] Step 2. Determine the window length and step size, and perform FFT processing on the signals intercepted in each window in turn by using the sliding window method according to the window length. FFT means fast Fourier transform; the meaning of the window means that different interception functions are used to process the signal. Truncation, the truncation function is called window function, referred to as window;
[0019] Step 3, determine the detection threshold, compare the amplitude of the frequency spectrum after the FFT of each window signal with the detection threshold, and record the position ...
specific Embodiment approach 2
[0023] The difference from Embodiment 1 is that in the method for extracting frequency of a frequency diversity signal in this embodiment, the process of determining that a certain position exceeds the threshold in Step 4 is as follows:
[0024] Step 41. Select a frequency diversity signal form that can simultaneously transmit sub-pulses of different frequencies: The simulation generates a frequency diversity signal for the next step of signal frequency detection; in the formula, A represents the amplitude of the sub-pulse signal, j represents the imaginary number unit, and its size is the square root of -1, f m Indicates a certain real frequency where the frequency diversity signal exists, t indicates the time independent variable, Represents the phase of each sub-pulse signal, M represents the number of frequencies existing in the signal, and exp represents the e exponential operator;
[0025] Step 42. Set sampling frequency and short-time Fourier transform related parame...
specific Embodiment approach 3
[0030] The difference from the second specific embodiment is that in the frequency extraction method of a frequency diversity signal in this embodiment, the false alarm probability formula is obtained as described in step 43: P f =1-(1-P K ) N The process is, because the noise always exists objectively, when the amplitude of the noise exceeds the detection threshold, the target will be misrecognized, this error is called false alarm, and the probability of false alarm is called false alarm probability, in the present invention , the probability that the frequency other than the frequency in the frequency diversity signal is misjudged as the frequency in the signal, that is, the probability that the frequency in the additive white noise is misjudged as the frequency in the signal is defined as the false alarm probability;
[0031] First, combine the noise energy E in each window obtained in step 1 NAnd by the window length N and Gaussian white noise variance The Gaussian wh...
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