Bit error measuring instrument

摘要

A pattern generating means, a multiplexing means, and a pattern position specifying-recording means of a testing device used for testing bit errors. An M-channel pattern generator and a pattern generation control section (10) which allows the pattern generator to output a pattern while successively switching the generating section of each channel and when a certain channel is selected to output a pattern, controls the pattern generating operations of the ondly, a clock frequency difference detecting section (150) which measures the frequency of an input clock (111), detects a frequency change that exceeds a prescribed frequency difference by comparing the measured frequency with the frequency value meajudges whether or not measurement is being conducted, and controls the permission/inhibition of the phase inverting operation of a clock switching circuit (128) is provided. Thirdly, a pattern position recording section (210) which stores the information about the reference pattern generating position of a reference pattern generator (262) in a recording memory (220) when an error detecting signal (265a) from a collating device (265) is detected, is provided.