CHANGING POINT DETECTING CIRCUIT, JITTER MEASURING APPARATUS AND TEST APPARATUS

摘要

A changing point detection circuit is provided that detects timing of changing points at which a logic value of a signal under measurement changes and includes a multi-strobe circuit generating a logic value data string obtained by detecting a logic value of the signal under measurement according to a plurality of strobes, each strobe having a different phase; a changing point detecting section detecting in which strobe the logic value changes based on the logic value data string; an edge designation storage section storing in advance information concerning whether an edge-type of the changing point to be detected is a rising edge or a falling edge of the signal under measurement; a selecting section selecting the changing point corresponding to the edge-type stored by the edge designation storage section from among the changing points detected by the changing point detecting section; and a strobe place storage section storing information concerning which strobe the changing point selected by the selecting section corresponds to.