Patent ID: 7746178

Claim:
A radio frequency (RF) circuit comprising: a first digital controlled oscillator (DCO) adapted to: receive a first digital control signal; and provide an RF output signal having a first frequency and a first phase, such that the first frequency is based on the first digital control signal; a first RF mixer circuit adapted to: receive a first local oscillator (LO) signal and the RF output signal; and provide a first intermediate frequency (IF) signal based on mixing the first LO signal and the RF output signal; a time-to-digital converter adapted to: receive and convert the first IF signal into a digital time representation of the first IF signal; and provide a first digital signal based on the digital time representation, such that the first digital signal is indicative of the first phase and the first frequency; and digital loop circuitry adapted to: receive a digital setpoint signal; receive the first digital signal; and provide the first digital control signal based on a difference between the digital setpoint signal and the first digital signal, wherein the first frequency is controlled to be about equal to a desired frequency represented by the digital setpoint signal.