To solve a problem such that an operator can hardly observe a change in an output potential level by an analog output circuit in the case of measuring an output jitter quantity in various phase synchronization circuit inside an LSI.
The jitter detection circuit is provided with a comparison pulse generating circuit 103 that converts a phase difference between 1st and 2nd input signals and provides an output, a periodic signal generator 104 that accumulates phase differences converted into the pulse width to generate a periodic signal, and a counter 105 that measures the period of the periodic signal and outputs the result as a digital numeral. Thus, the jitter detection circuit can easily execute calculation of a mean value over a plurality of periods and calculation of variances being an indices for transition of a change or the like.
MICHIMASA SHIRO
NISHIKAWA KAZUHIKO
WATANABE SEIJI
ENOI TAKAHIRO
