Patent ID: 6888413

Claim:
A frequency synthesizer comprising: a phase locked loop including a signal controlled oscillator (SCO), a programmable frequency divider for dividing a signal from the SCO, a first controller to provide the divide ratio to said programmable divider, a reference source, a phase detector for comparing a signal from said reference source with an output signal of said divider and generating a phase detector signal related to the phase difference therebetween, and a loop filter for filtering the phase detector signal and providing a SCO control signal for controlling the frequency of said SCO; a frequency range controller coupled to the SCO that includes switchable elements, each providing a different frequency range of operation of the SCO under control of a switch input; a calibrator to relate the switch input to frequency ranges; a sensor coupled to the control signal of the SCO providing a measurement that varies as the magnitude of the control signal, said sensor having more than two output values that vary as the magnitude of the control signal; and a second controller accepting the magnitude indication and having an output coupled to the switch input of the range controller to maintain the operating point of the SCO close to a desired operating point.