A Frequency Domain Parameter Measurement Method of Chirp Signal

Abstract

The invention discloses a frequency domain parameter measurement method for linear frequency modulation signals. The method includes steps of S1, time domain data acquisition comprising performing time domain windowing on signals so as to divide signals into a plurality of data segments; S2, data conversion comprising performing discrete Fourier transform on the data segments and obtaining sub band frequency spectrums of the data segments; S3, frequency spectrum interpolation comprising performing interpolation treatment on each sub band frequency spectrum and obtaining frequency spectrum signals subjected to point extension corresponding to each data segment; S4, frequency spectrum time delay comprising adding time domain delay information on the frequency spectrum signals subjected to point extension; S5, frequency spectrum synthesis comprising performing frequency spectrum synthesis on all the frequency spectrum signals with time domain delay information and restoring a complete frequency spectrum of original signals; S6, frequency domain parameter measurement comprising performing frequency domain parameter measurement by utilizing the restored complete frequency spectrum. According to the invention, the original signal frequency spectrum is restored by utilizing short term frequency spectrum and more frequency spectrum information of the original signals are obtained through fitting, frequency resolution rate is improved and therefore the bandwidth and start frequency measurement precision is improved.

Description

technical field [0001] The invention relates to frequency domain parameter measurement, in particular to a method for frequency domain parameter measurement of linear frequency modulation signals. Background technique [0002] In the process of signal detection in the air domain, short-time Fourier transform (STFT) is a commonly used processing method in order to obtain the frequency domain parameters in the pulse description word of the intercepted signal in time, such as bandwidth, initial frequency or center frequency. ; By sliding the window in the time domain to the signal, the signal is divided into shorter data segments, and then DFT (discrete Fourier transform) is performed on each short-term signal to obtain the sub-band spectrum, and the corresponding frequency domain information is analyzed, but For modulated signals such as linear frequency modulation (LFM), the spectrum of each short-term data segment cannot accurately reflect the frequency domain information of...

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Problems solved by technology

[0002] In the process of signal detection in the air domain, short-time Fourier transform (STFT) is a commonly used processing method in order to obtain the frequency domain parameters in the pulse description word of the intercepted signal in time, such as bandwidth, initial frequency or center frequency. ; By sliding the window in the time domain to the signal, the signal is divided into shorter data segments, and then DFT (discrete Fourier transform) is performed on each short-term signal to obtain the sub-band spectrum, and the corresponding frequency domain information is analyzed, but For modulated signals such as linear frequency modulation (LFM), the spectrum of each short-term data segment cannot accurately reflect the frequency domain information of the original complete signal. figure 1 Schematic diagram for spectral analysis of signals within a narrow data window (short-time signal spectrum), figure 2 is the original signal spectrum. Comparing the two figures, it can be seen that each segment of the spectrum only reflects part of the spectrum information of the original signal, and the measurement of the spectrum parameters of each sub-band is affected by the frequency resolution, etc., and the frequency measurement error is large. Further acquisition of sub-band measurement parameters such as the bandwidth and center frequency of the original signal will inevitably bring large errors

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