Patent ID: 8259859

Claim:
A method of carrier recovery in a digital receiver, the receiver configured to receive radio frequency signals modulated with data including a complex transmitted symbol having an in-phase component and a quadrature component, and to determine a frequency offset direction, the method comprising: demodulating, in a demodulator, the received radio frequency signals to produce the in-phase and the quadrature components of the complex transmitted symbol; determining a first phase error at a first time and a second phase error at a second time; determining a phase error differential between the first phase error at the first time and the second phase error at the second time; determining an offset confidence number based at least in part on the phase error differential; determining the frequency offset direction based at least in part on the offset confidence number; wherein the offset confidence number is indicative of a degree of certainty of the determined frequency offset direction; and comparing the offset confidence number to a first threshold value.