| 摘要 |
PROBLEM TO BE SOLVED: To reduce the processing load of frequency tracking a clock and data recovery circuit, thereby making it possible to improve characteristics of the circuit.SOLUTION: A semiconductor device comprises: a frequency tracking loop which, upon receiving the result of detection by a phase detector which detects lead or lag in phase between input data and an extraction clock signal, controls the input data and the extraction clock signal so that a frequency deviation between the two is reduced; and a phase interpolator which, on the basis of the frequency deviation detection result in the frequency tracking loop, adjusts the phase of a spread spectrum frequency modulated clock signal before outputting the extraction clock signal. In the frequency tracking loop, a frequency deviation between the data signal and the clock signal is corrected on the basis of frequency modulation information regarding the spread spectrum frequency modulated clock signal which is input to the phase interpolator, whereby a frequency fluctuation of the clock signal is offset, so that the clock signal appears to be tracking the frequency of the data signal. |
