Journal of Applied Mathematics and Decision Sciences
Volume 2006 (2006), Article ID 53649, 13 pages

Analysis of FM demodulator output noise with applications to FM telemetry

Rajendra Kumar

Department of Electrical Engineering, California State University, Long Beach, CA 90840, USA; Communications Systems Department, The Aerospace Corporation, El Segundo 90245-4691, CA, USA

Received 9 December 2005; Revised 10 February 2006; Accepted 20 February 2006

Copyright © 2006 Rajendra Kumar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We present an analysis for evaluating the probability density function (pdf) of the noise at the output of the frequency demodulator. It is shown that the noise is non-Gaussian and that for low to medium signal-to-noise power ratios, its pdf differs very significantly from the Gaussian pdf commonly assumed in simplified analysis. These results are very important for analyzing the performance of the PCM/FM type of modulation schemes used in telemetry systems as illustrated in the paper.