Patent ID: 7301416
Filing Date: 2007-11-27
Classification: H03J,H03L

Abstract:
1. A semiconductor integrated circuit for wireless communication, comprising: a transmission-system circuit including, switching means capable of supplying a potential of a predetermined level to the first oscillator as a control voltage in a state in which the loop is opened; a variable divider which divides the output signal of the first oscillator at a designated division ratio; a constant divider which divides a reference signal having a predetermined frequency at a predetermined division ratio; a band selection circuit which compares the phase of an output signal of the variable divider with the phase of an output signal of the constant divider in a state in which the potential is supplied to the first oscillator by the switching means to thereby select an oscillation frequency band for the first oscillator; and timing control means which controls a timing provided for the reference signal in such a manner that the phase of a second signal which corresponds to the output of the constant divider and is used in the band selection coincides with the phase of a first signal formed based on the output signal of the variable divider and used in the band selection, wherein the timing control means delays the timing for the reference signal by a time equivalent to a delay time from the release of reset of the variable divider to the output of the signal therefrom.