Study on Multipath Effect under the Environment of PCM/FM Telemetry Soft Demodulation

Abstract

Because the reentry telemetry wireless channel multipath propagation effects and the effect, channel will introduce transmission time delay dispersion, caused between the PCM/FM telemetry signal crosstalk and signal to noise ratio is too low, significantly increase BER. While traditional demodulation method because the demodulator threshold higher no longer apply. Study the problem, a multiple Symbol Detection method based on sliding strategy (Multi - Symbol Detection, MSD), can effectively overcome the low SNR and inter symbol interference. The simulation and test results verify the effectiveness of the method.