IMPEDANCE MATCHING DEVICE AND ENDOSCOPE PROVIDED WITH SAME

摘要

An impedance matching device comprises: a cable which transmits a square wave output from a solid-state imaging element; a double-correlated sampling circuit which fixes the timing of a feed-through sampling pulse to a timing exhibiting a high value for a square wave transmitted by the cable, and which conducts double-correlated sampling in such a way that the square wave is scanned by means of the square wave being sampled while the timing of a signal clamp pulse is varied based on the fixed timing of the feed-through sampling pulse; a variable resistor which is provided on the terminal side of the cable and has a variable resistance value; and a resistance value variation means which changes the resistance value of the variable resistor in such a way that the resistance value of the variable resistor matches the characteristic impedance of the cable, the resistance value of the variable resistor being changed on the basis of a signal that is output from the double-correlated sampling circuit as the result of scanning that is performed while the resistance value of the variable resistance is varied.