Patent ID: 8509363

Claim:
An FM radio receiver comprising: a local oscillator configured to receive a combined local oscillator control signal and generate a local oscillator frequency; a mixer configured to mix the local oscillator frequency and an FM radio input signal to generate a downconverted signal; an analog to digital converter (ADC) configured to digitize the downconverted signal and to provide a digitized signal; a demodulator configured to receive the digitized signal and generate a digital error signal and a baseband signal including FM radio information; a digital synthesizer circuit configured to generate a first local oscillator control signal corresponding to an estimate of a desired local oscillator frequency, the digital synthesizer circuit including a counter configured to receive a reference frequency and an output of the local oscillator, a digital accumulator configured to receive and accumulate an output of the counter, and a synthesizer scaling element configured to receive the accumulated output; a digital automatic frequency control (AFC) circuit configured to receive the digital error signal and generate a second local oscillator control signal corresponding to the desired local oscillator frequency, the digital synthesizer circuit being enabled to generate the local oscillator control signal when the digital AFC circuit is disabled, the digital AFC circuit being enabled to generate the second local oscillator control signal when the digital synthesizer circuit is disabled; and a combining element combining the first local oscillator control signal and the second local oscillator control signal to form the combined local oscillator control signal.