Patent ID: 7245657
Filing Date: 2007-07-17
Classification: H04L

Abstract:
1. A jitter tolerance measurement apparatus comprising: a modulation signal generator which outputs a modulation signal having a variable frequency and a variable amplitude; a clock signal generator which generates a clock signal having a variable frequency, receives the modulation signal output from the modulation signal generator, generates jitter based on the modulation signal on the clock signal, and outputs the clock signal provided with the jitter; a pulse pattern generator which receives the clock signal provided with the jitter, output from the clock signal generator, generates a data signal having a predetermined pattern, and supplies the data signal to a measurement subject; an error detector which receives a data signal having the predetermined pattern output from the measurement subject that operates based on the data signal having the predetermined pattern output from the pulse pattern generator, compares the data signal with a preset data sequence having a predetermined pattern, and thereby measures errors in the data signal having the predetermined pattern output from the measurement subject; a decision section which decides whether or not errors output from the error detector are in a preset reference range, and outputs a decision result; a control section which conducts control to vary the amplitude of the modulation signal every time the control section conducts control to vary a combination of a frequency of the clock signal and a frequency of the modulation signal by controlling the clock signal generator and the modulation signal generator, and derives a value indicating jitter tolerance of the measurement subject based on the decision result and information of the amplitude of the modulation signal; and a display section which receives information concerning the frequency of the clock signal, the frequency of the modulation signal, and the amplitude of the modulation signal that are controlled by the control section, and the value indicating jitter tolerance, and displays jitter tolerance characteristics of the measurement subject simultaneously on a screen by using the frequency of the clock signal and the frequency of the modulation signal as two parameters.