Decrease the demodulation threshold in FM demodulator with quadratic de-noising method

The application of adaptive noise feedback control on a FM demodulator greatly decreases distortion and noise sensitivity in the demodulation of wide-band FM signals. In this paper, the approach for FM signal demodulation using the RLS algorithm of adaptive filters and noise decision feedback loop is proposed. The white noise signals can be effectively estimated and eliminated with the RLS algorithm of adaptive filters. FM modulation signal constant envelope characteristic decision feedback loop can be used to extend the threshold of signal-to-noise improvement in large index FM demodulation systems. Experimental simulation results shows that: Compared with a traditional digital demodulation, the antinoise performance of the novel FM demodulation model is greatly improved and the threshold of the novel FM demodulation model is 3dB lower than the others.