A discrete-time method of demodulating large deviation FM signals

A method of enhancing the performance of a numerical FM discriminator in specific receive-signal conditions, using frequency feedback techniques, is developed and evaluated. Receive-signal conditions of interest are: 1) frequency deviations that are large relative to the bandwidth of the message signal; 2) a low-uniform (complex) sample rate commensurate with the bandwidth; and 3) noise strengths that yield values of input carrier-to-noise ratio of the order of 10 dB or more. Through computer simulation, observed phase cycle-slip counts and phase noise variance estimation are used to compare the enhanced demodulator to the performance of a numerical FM discriminator baseline. Based upon the theoretical analyses and simulation results, the presented method of numerical FM demodulation is shown to be a viable technique For enhancing the performance of numerical FM discriminators under the given modulation conditions.