Patent ID: 7020444
Filing Date: 2006-03-28
Classification: H03B,H03D,H03J,H03L

Abstract:
1. A communication semiconductor integrated circuit, comprising: a first, a second, and a third oscillator circuit each capable of oscillating in a plurality of frequency bands; one or two or more frequency counters for measuring oscillating frequencies of said first, second, and third oscillator circuits; storage means for storing results of measurements on the oscillating frequencies made by said frequency counter in each of the frequency bands of said first, second, and third oscillator circuits; and a control circuit for applying a predetermined DC control voltage to said first, second, and third oscillator circuits to oscillate at respective oscillating frequencies, and for controlling said frequency counter to measure the oscillating frequencies and store the measured frequencies in said storage means, said control circuit configured to determine operating frequency bands for said first and second oscillator circuits based on set frequency information for said first and second oscillator circuits, and the results of measurements stored in said storage means, and to determine an operating frequency band for said third oscillator circuit based on the set frequency information for said first and second oscillator circuits, and the results of measurements stored in said storage means.