Abstract: A data-pattern feedback mechanism is introduced into the peak detection process of an automatic frequency compensation system in a Gaussian Frequency Shift Keying (GFSK) modulated system, providing fast and accurate fine-stage automatic frequency compensation (AFC). Maximum positive and negative peak registers are updated with new values as necessary based on detection during a sequence of identical binary bit values (e.g., during a “00” for detection of maximum negative peak frequency, or during a “11” for detection of maximum positive peak frequency), in a particular data frame. As soon as an initial value is determined for both the maximum positive and negative peak frequencies (e.g., after the first occurrence of a “11” and a “00”, in any order), fine-stage automatic frequency compensation can be initiated. Subsequent adjustments to the VCO of the local oscillator will further refine the frequency offset towards the ideal of zero.

Abstract: A data-pattern feedback mechanism is introduced into the peak detection process of an automatic frequency compensation system in a Gaussian Frequency Shift Keying (GFSK) modulated system, providing fast and accurate fine-stage automatic frequency compensation (AFC). Maximum positive and negative peak registers are updated with new values as necessary based on detection during a sequence of identical binary bit values (e.g., during a “00” for detection of maximum negative peak frequency, or during a “11” for detection of maximum positive peak frequency), in a particular data frame. As soon as an initial value is determined for both the maximum positive and negative peak frequencies (e.g., after the first occurrence of a “11” and a “00”, in any order), fine-stage automatic frequency compensation can be initiated. Subsequent adjustments to the VCO of the local oscillator will further refine the frequency offset towards the ideal of zero.