Patent ID: 7496170

Claim:
A signal generator circuit having enhanced control resolution, comprising: a variable frequency oscillator including a first control input adapted to receive a first signal and at least a second control input adapted to receive a second signal, the second signal being afforded a weight which is substantially equal to a weight of a least significant bit of the first signal, the variable frequency oscillator being operative to generate an output signal having a frequency which varies as a function of the first and second signals; a comparator configurable for receiving a third signal and a fourth signal, the third signal being an input signal presented to the signal generator circuit and the fourth signal being representative of the output signal from the variable frequency oscillator, the comparator generating a difference signal representative of a difference between at least one of a phase and a frequency of the third and fourth signals; a first counter configurable for generating an output count based at least in part on the difference signal from the comparator, the output count being a digital representation of the difference signal, the output count comprising the first signal; a first divider connected between the variable frequency oscillator and the comparator, the first divider having a selectable divide value associated therewith and being configurable for receiving the output signal from the variable frequency oscillator and for generating the fourth signal based on the divide value; and a modulation circuit adapted to receive at least a portion of the output count and the fourth signal and to generate the second signal as a function of the output count and the fourth signal.