DEVICE AND METHOD FOR FM DEMODULATION WITH THRESHOLD EXTENSION

摘要

The present disclosure is directed to an FM demodulator having an extended threshold breakdown point. The FM demodulator uses an arcsin demodulator in combination with a frequency compressive loop to produce a demodulated output signal. The FM demodulator includes three filters that use a coefficient α to determine how the filters behave. The FM demodulator extends the threshold breakdown point of the signal-to-noise ratio of the FM signal beyond traditional levels, allowing the FM demodulator to work at long distances from the broadcasting antenna.

主权项

1. A device, comprising:
a first mixer that receives a frequency modulation (FM) signal and an error reference signal, and produces an error difference signal; a first filter coupled to the first mixer that receives the error difference signal and produces a filtered signal having a frequency removed based on a first coefficient; an arcsin FM demodulator coupled to the first filter that receives the filtered signal and produces a demodulated signal; a second filter coupled to the arcsin FM demodulator that receives the demodulated signal and produces a detected error signal based on the first coefficient at an output; an error circuit including an FM modulator coupled to the second filter that receives the demodulated signal and produces the error reference signal; and a third filter coupled to the output of the second filter, the third filter receiving the detected error signal and producing an output signal.