A Test Method for Linear Frequency Modulated Strong Pulse Field Using Time-Frequency Combination

In order to measure the linear frequency modulated (LFM) strong pulse field generated by high-power radars, a test method using time-frequency combination is proposed. On the basis of deriving the expressions of LFM pulse signal power, a measurement and evaluation method in time domain is given. According to the principle of root mean square (RMS) detection, a measurement and evaluation method in frequency domain is put forward. Through the combination of the two, the parameters of the LFM pulse field can be obtained such as the peak field strength, average field strength, pulse width, pulse repetition period and spectrum distribution. If the resolution bandwidth for the spectrum analyzer is greater than the occupied bandwidth of the LFM pulse signal, the measured results in the time domain and frequency domain can be mutually verified. The experiments are carried out to verify the method. The results show that the measured deviations of the peak field strength and average field strength of the LFM pulse field are not more than 2 dB, which indicates the test method is effective and feasible. It can meet the measurement requirements of LFM strong pulse field even if modulation parameters are unknown.