A method includes, at a frequency shift keying (FSK) demodulator, determining a likelihood of a symbol having a first symbol value or a second symbol value, using the likelihood of the symbol to select either the first symbol value or the second symbol value for the symbol, the first symbol value or the second symbol value that is selected being a selected symbol value, selecting a frequency error from a first frequency error or a second frequency error, and using a down-mixer and the frequency error to correct a frequency drift associated with a future selected symbol value.