| 摘要 |
PROBLEM TO BE SOLVED: To calibrate timing in a short time by providing an IC socket with a short-circuit device short-circuiting signal pins to one point, and calibrating take-in timing with a reflection signal of calibration pulse reflected from the short-circuit point. SOLUTION: At calibrating timing, a short-circuit device 70 is mounted to an IC socket 33, and all signal pins. excluding power pins are connected in common. Calibration pulses are outputted to all the pins by a timing and waveform generator 10, and the calibration pulses are applied to the short-circuit device 70 via each driver DR and cable 36 and reflected from the same short- circuit point. Reflected waves have the average value of voltage of all the calibration pulses. Each voltage comparator CP sets reference voltage VREF applied thereto, to the half of amplitude of the reflected wave, and detects the timing of a rising half part. Variable delay elements PAVD1, PAVD2, of a timing calibrator 11 are thereby adjusted to calibrate the applied timing of strobed pulses.
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