An FSK receiver comprising: 1) demodulation circuitry for receiving an incoming
FSK signal and generating a baseband signal comprising an amplitude modulated symbol
stream of Logic 0 symbols and Logic 1 symbols having a data rate, R; 2) auto-correlation
circuitry for sampling the baseband signal S times during each symbol and generating
an auto-correlation function comprising a sample stream of N-bit samples having
a data rate, SR, and having positive-going peaks approximately coinciding
with the center of the Logic 1 symbol in a 010 sequence in the baseband signal
and negative-going peaks approximately coinciding with the center of the Logic
0 symbols in a 101 sequence in the baseband signal; and 3) decision circuitry for
receiving the auto-correlation function and deciding a logic level of a first symbol
as a function of: 1) a comparison of a signal level of a center sample of the first
symbol and a mean signal level of the auto-correlation function and 2) a comparison
of the signal level of the center sample of the first symbol and a signal level
of a center sample of a second symbol preceding the first symbol.
