US Patent 7684944 Calibration apparatus, calibration method, and testing apparatus

There is provided a calibration apparatus that calibrates a jitter measuring circuit for outputting a jitter measuring signal with a level according to an amount of jitter in an input signal based on the input signal and a delay signal obtained by delaying the input signal by means of a variable delay circuit. The calibration apparatus includes a delay control section that sequentially sets a first delay amount and a second delay amount in the variable delay circuit and a gain computing section that computes gain in the jitter measuring circuit based on the jitter measuring signal respectively output from the jitter measuring circuit for the first delay amount and the second delay amount.