Patent ID: 7263153

Claim:
A device that communicates with a host, comprising: a transmitter; a receiver; a clock generator that generates a signal having a local clock frequency; a clock recovery circuit that communicates with said receiver and that recovers a host clock frequency from data received from said host by said receiver; a frequency offset circuit that communicates with said clock recovery circuit and said clock generator and that generates a frequency offset based on said clock frequency and said recovered host clock frequency; a frequency compensator that compensates a frequency of said transmitter using said frequency offset, wherein said frequency compensator includes a low pass filter that communicates with said frequency offset circuit, said frequency compensator includes an accumulator that communicates with said low pass filter and that generates a phase offset, said frequency compensator includes an interpolator that receives a local phase from said clock generator and said phase offset from said accumulator, and said interpolator outputs a compensated clock signal to said transmitter; a summer having a first input that communicates with an output of said lowpass filter and an output that communicates with an input of said accumulator; and a frequency modulation generator that communicates with a second input of said summer and that selectively generates a spread spectrum modulation signal when spread spectrum operation is enabled and a constant signal when spread spectrum operation is disabled.