| 摘要 |
PURPOSE:To easily measure the quantity of delay of a delay circuit to be tested by obtaining a delay test signal from a test signal with a variable period, supplying the signal to the delay circuit to be tested, and comparing the phase of the output of the delay circuit to be tested with the phase of the test signal. CONSTITUTION:A rectangular wave signal with a period Tx is inputted from a test signal generating circuit through an input signal line 1. The period of an input signal when a phase comparator PC0 detects signals on an output signal line 3a and an input signal line 1 being in phase with each other is denoted as Ta. Similarly, when a coincident with PC1is obtained, it is denoted as Tb. Then, signals on output signal lines 3a-3f are delayed behind the signal on the input signal line 1 by a specific quantity. Therefore, respective phase comparators PC0-PC5 know terminals 5a-4f where in-phase signals are outputted and a high level is obtained, so that the delay time of the delay circuit DUU is tested. |
