Matched Filtration of LFM Signals with Non-Zero Initial Frequency

Abstract

This paper presents the results of the research considering the in uence of the initial frequency on linear frequency modulation signal compression. The signal compression has been performed using the digital matched ltration in the time domain. The ratio of peak to side lobe ratio with the width of the main lobe equaling one sampling period is the measure of the quality of compression. In general, a lower value of peak to side lobe ratio is obtained for linear frequency modulation signals with a non-zero initial frequency than with a zero initial frequency. The peak to side lobe ratio is systematically decreasing with the increase of the initial frequency f1. The existing methods of band signals sampling, where the spectrum of the signals is transferred by means of the carrier signal f0 of a signi cantly higher frequency than the band B (f0 B) may be e ectively used for sampling signals considered in this study, which do not have a carrier. As a result, for the linear frequency modulation signals with a non-zero initial frequency f1 = nB and a nal frequency f2 = (n + 1)B, n = 1, 2, . . ., the same peak to side lobe ratio values will be obtained as for linear frequency modulation signals with a zero initial frequency and the identical band and time duration. The results of this research could be implemented in sonar and radiolocation techniques and medicine.