Patent ID: 7834642
Filing Date: 2010-11-16
Classification: G01R

Abstract:
1. A test apparatus for testing a device under test, comprising: a first timing comparator that obtains a device output signal output from the device under test at a timing designated by a first strobe signal; a second timing comparator that obtains the device output signal at a timing designated by a second strobe signal, the second strobe signal being supplied later than the first strobe signal; a preceding edge judging circuit that, when a rising signal and a falling signal are input at the same timing as the device output signal, judges which one of the rising and falling signals arrives at the first and second timing comparators at an earlier timing; a preceding edge detecting circuit that adjusts a timing at which the first strobe signal is supplied so that the first timing comparator obtains, at a timing of a rising or falling edge, one of the rising and falling signals which is judged to arrive earlier; and a following edge detecting circuit that adjusts a timing at which the second strobe signal is supplied so that the second timing comparator obtains, at a timing of a rising or falling edge, one of the rising and falling signals which is judged to arrive later.