DSP based self-tuning BFSK demodulation

Conventional FSK (frequency shift keying) demodulators are generally designed around fixed operating parameters, with the result that received signals must be carefully tuned to exactly match standard MARK/SPACE frequencies. A self-tuning BFSK (binary FSK) demodulator is described, based on a uniform-sample-rate digital dynamic Costas lock loop (DDCLL). The demodulator operates over a wide range of tuned inputs by extracting the instantaneous frequency of a voice-band sinusoidal carrier. A second stage analyzes the frequency content of the signal to established dynamic thresholds for MARK/SPACE conditions. An overall description of the TMS320C30-based BFSK demodulator is provided, along with preliminary test results using real-time BFSK signals and testing signals