Maximum time interval error test signal generating apparatus not affected by low-pass measuring filter

摘要

A Maximum Time Interval Error test signal generating apparatus (20) generates a predetermined MTIE test signal which enables measurement of a predetermined MTIE characteristic based on that signal by inputting a clock signal from a reference clock generator (15) modulated by a predetermined MTIE test signal in terms of phase to an MTIE measuring unit (18) including a low-pass measuring filter (18a) having a predetermined high-cut characteristic at an input portion thereof. A cycle-amplitude setting portion (22) sets a cycle corresponding to an observation time of each of desired plural specific points for a predetermined MTIE characteristic of plural MTIE characteristics and an amplitude corresponding to a difference in the MTIE value between adjacent specific points of the desired plural specific points. Plural signal generating portions (24(1), 24(2), ... 24(n)) generate plural signals each having a cycle corresponding to an observation time of each of the desired plural specific points and an amplitude corresponding to a difference in MTIE value between adjacent specific points of the desired plural specific points, the cycle and amplitude being set by the cycle-amplitude setting portion (22) and having repetitive waveforms in which after the signal amplitude increases from its lower limit value to its upper limit value during each observation time, it decreases from the upper limit value to the lower limit value and then outputting to each of the desired plural specific points. A synthesizing portion (25) synthesizes the plural signals output from the plural signal generating portions (24(1), 24(2), ... 24(n)) by summing and outputs as the predetermined MTIE test signal. A holding time setting portion (23) sets a holding time for holding the upper limit value and the lower limit value of the repetitive waveform of the signal over the predetermined time so that a signal cycle having at least the shortest cycle of the plural signals generated by the plural signal generating portions (24(1), 24(2), ... 24(n)) is longer than a predetermined time corresponding to the predetermined high-cut characteristic of the low-pass measuring filter in the MTIE measuring unit.