A Method of Simultaneous Signals Spectrum Analysis for Instantaneous Frequency Measurement Receiver

摘要

In this paper the simplified problem of frequency determination for multiple simultaneously present harmonic oscillations through subsampling is considered. The proposed (used) subsampling is realized by Dirac function comb with principal frequency much less than input signal frequencies. So all signal frequencies are transformed to first Nyquist zone. We consider subsampling is implemented in three parallel channels when comb principal frequencies are differing but close one to another. Each channel includes also ADC, FFT unit and digital processing unit. Output channel information is a set of possible input frequencies, and these sets intersection is searched for finding input frequencies. Proposed system math model was developed for estimation of ambiguity of recovering values for original input frequencies. The subsampler with three parallel channels was realized as a small unit. It works as mixer with comb type heterodyne in superheterodyne receiver. The subsampler has analog bandwidth up to 5 GHz with 100 MHz principal frequencies. Its experimental characteristics are presented.