Patent ID: 7205850
Filing Date: 2007-04-17
Classification: H03C,H03D,H03J,H03L,H04B

Abstract:
1. A semiconductor integrated circuit device for communication use, said device comprising: an oscillation circuit for generating an oscillation signal with a frequency pursuant to an externally set value; a first frequency division circuit for frequency division of the oscillation signal as generated by said oscillation circuit to thereby generate a signal of intermediate frequency; a modulation circuit for modulating the signal as frequency-divided by said first frequency division circuit; a first frequency conversion circuit for converting a signal modulated by said modulation circuit into a transmission signal with higher frequency; and a second frequency conversion circuit for combining together a signal taken out of the output side of said first frequency conversion circuit and a signal as frequency-divided by a second frequency division circuit to thereby generate a signal with its frequency equivalent to a frequency difference between these signals, said first frequency conversion circuit being arranged to form a transmission signal based on the signal converted by said second frequency conversion circuit and the signal modulated by said modulation circuit, wherein said oscillation circuit includes an oscillator, a programmable frequency divider capable of frequency-dividing an oscillation signal of the oscillator in accordance with a frequency division ratio supplied thereto, a phase comparator for detection of a phase difference between an output signal of the programmable frequency divider and a reference signal, and frequency control means for outputting a voltage or a current pursuant to the phase difference detected by said phase comparator and for controlling the oscillation frequency of said oscillator, and said device comprises a frequency division ratio generation circuit for generating an integer part I and a fraction part F/G based on band information concerning an externally supplied use frequency band and mode information indicative of whether signal transmission or reception and channel information as to a setup frequency, and for generating the frequency division ratio based on said integer part I and fraction part F/G.