Abstract: When the multi-frequency signal is sampled asynchronously, in order to reduce the negative influence of the frequency spectrum leakage and the fence effect in the fast Fourier transform of the multi-frequency signal. Based on the theoretical basis of rectangular convolution window and the triple-spectral-line interpolation, proposed a method of signal parameter estimation that combines a high-order rectangular convolution window and triple-spectral-line interpolation. The simulation experiment results show that, for the amplitude and frequency of the multi-frequency signal, the method of high-order rectangular convolution window triple-spectral-line interpolation has higher estimation accuracy than the method of FFT and the method of Hanning window.

Key words: multi-frequency signal, parameter estimation, high-order rectangular window, triple-spectral-line interpolation, fast Fourier transform