Patent ID: 8358159

Claim:
In a phase-locked loop (PLL), a method for adaptive multi-band frequency calibration comprising: initially selecting a voltage controller oscillator (VCO) nominally associated with a first synthesized signal frequency in a first frequency band, where the VCO is selected from a plurality of n VCOs, and each VCO is tunable across a band of synthesized signal frequencies in m consecutive, partially overlapping, adjacent bands; a lock detector comparing a nominal first synthesized signal frequency to a reference signal frequency; in response to sensing a difference between the nominal first synthesizer and reference signal frequencies, asserting an out-of-lock condition; in response to the out-of-lock condition, reselecting a VCO from the plurality of n VCOs; supplying a mid-point control voltage to a control voltage input of the reselected VCO; measuring a difference between a mid-point synthesized signal frequency and the reference signal frequency; and, in response to the difference being less than a first threshold, assigning the reselected VCO to generate the first synthesized signal frequency.