Patent ID: 7352190

Claim:
A calibration apparatus that calibrates a jitter measuring circuit, the jitter measuring circuit comprising: a jitter signal generating section that generates a jitter signal of which duration of at least one of High logic or Low logic changes according to a jitter in an input signal; and an integrating section that charges and discharges a capacitor with a predetermined electric current according to the logical value of the jitter signal to integrate the jitter signal and outputs a jitter measuring signal with a level according to an amount of jitter in the input signal, and the calibration apparatus comprising: a current control section that makes the integrating section output at least one of a predetermined charging current and a predetermined discharging current for charging and discharging the capacitor; a voltage measuring section that measures voltage variation of the capacitor in a state where the charging current or the discharging current is output by the current control section; and a gain computing section that computes gain of the integrating section based on the voltage variation measured by the voltage measuring section.