Method to Reduce the Measurement Error of the Spectrum by the Demodulation Technique

This article gives an overview of the main approaches for measuring the spectrum of the signal. The method of measurement spectrum based on using a demodulator is considered. The main advantages and disadvantages of the considered method are shown and are compared to the popular method based on discrete Fourier transform. The method which consists in averaging the instantaneous measurement results of the spectrum allows to significantly reduce the additional measurement error of amplitude and phase spectrum is proposed. The reliability of the obtained analytical expressions is confirmed by the coincidence of the results of analytical and simulation modelin performed using the software packages Matlab and Simulink.