Patent ID: 7760839
Filing Date: 2010-07-20
Classification: H04B

Abstract:
1. An offset controllable spread spectrum clock generator apparatus, comprising: a spread spectrum clock generator (SSCG), for spreading a received original clock signal and outputting a first spread spectrum clock signal; a controllable delay circuit coupled to the SSCG, for delaying the first spread spectrum clock signal according to a control signal to output a second spread spectrum clock signal; and a control unit coupled to the controllable delay circuit, for making statistical analyses of the second spread spectrum clock signal according to the timing of the original clock signal, and adjusting and outputting the control signal to the controllable delay circuit according to the results of the statistical analyses; wherein the control unit comprises: a sampler unit, for sampling the second spread spectrum clock signal according to the timing of the original clock signal to output a sample result; a counter coupled to the sampler unit, for making statistical analyses of the sample result and outputting a number of leading times and a number of lagging times accordingly; and a controller coupled to the counter, for receiving and comparing the number of leading times and the number of lagging times, and adjusting and outputting the control signal according to the comparison result.