Patent ID: 8274337

Claim:
A semiconductor integrated circuit comprising: an oscillation-frequency-signal generating unit that comprises a plurality of digitally controlled oscillators, oscillation frequencies of oscillation signals of which are controlled according to an oscillator tuning word; a phase-data output unit that outputs a plurality of phase data that are added up count values obtained by counting numbers of waves of the oscillation signals and phase differences between the oscillation frequencies of the oscillation signals and a reference frequency; an integration processing unit that outputs integration values of frequency setting data of the digitally controlled oscillators in synchronization with the reference frequency; a filter unit that filters a difference value, in synchronization with the reference frequency, between the phase data from the phase-data output unit and the integration value from the integration processing unit; and a gain adjusting unit that outputs the oscillator tuning word obtained by multiplying output signals from the filter unit with a predetermined coefficient to the oscillation-frequency-signal generating unit as in synchronization with the reference frequency.