| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a spread spectrum clock generator which enhances the resolution and reduces the peaks of a frequency spectrum. <P>SOLUTION: The spread spectrum clock generator 100 includes: a phase comparator 20 which detects a phase difference of a reference clock signal and a feedback clock signal; a charge pump 22; a loop filter 24; a multi-phase VCO 22 which generates multi-phase clock signals; a phase interpolation unit 120 which interpolates adjacent phase clock signals from the multi-phase VCO 26; a phase selection unit 130, which controls phase selection of the phase interpolation unit 120; a modulation data unit 140, which memorizes modulated wave form data for one period which changes in steps by a fixed step width; a dither processing unit 150 which outputs a dither step signal DS; and an adder 160, which adds the modulated wave form data and the dither step signal. The phase selection unit 130 performs phase interpolation, based on the modulated wave form data with the dither step signal added. <P>COPYRIGHT: (C)2010,JPO&INPIT |
