Patent ID: 6590461
Filing Date: 2003-07-08
Classification: H03L

Abstract:
A frequency conversion apparatus which generates an output signal having a frequency equivalent to a coefficient multiple of a frequency of a reference clock signal, said apparatus comprising:a) variable oscillation means for generating a group of clock signals having phase differences obtained by dividing substantially equally a period of the output signal; b) main-phase selection means for selecting and outputting, from said group of the clock signals, a pair of the two clock signals of desired adjacent phases on the basis of a first control signal; c) sub-phase selection means for selecting and outputting, from said pair of the clock signals and a clock phase within the phase difference of these signals, the one clock signal on the basis of a second control signal; d) operation processing means for performing an operation process by using two frequency setting data; e) logical control means for generating the first and second control signals on the basis of the clock signal selected by said sub-phase selection means, the operation result of said operation processing means, and a phase change control signal; f) phase comparison means for outputting a phase difference signal representing a phase difference between the clock signal selected by said sub-phase selection means and the reference clock signal; and g) control means for controlling said variable oscillation means on the basis of the phase difference signal output by said phase comparison means.