| 摘要 |
PURPOSE:To keep the difference in phase constant regardless of the length of a cable, by detecting the difference of a driving signal with a reflected wave in phase that is caused by a mismatching of impedance and controlling to always keep the difference in phase at the control level. CONSTITUTION:The drive pulse of a camera head is transmitted through an input/ output terminal 8, and at the same time the reflected wave caused by a mismatching of impedance is accepted. If the length of a cable is increased, the reflected wave delays from the transmitting pulse in phase by an amount equivalent to a change of the cable length. As a result, the pulse width is reduced for the output pulse (i) of an FF3 to which the drive pulse supplied from an input terminal 9 and pulses (c) and (h) having the same phase as the reflected wave are supplied. The pulse (i) is applied to an operational amplifier 4 and a monostable multivibrator 5, and thus a pulse having advanced phase that the drive pulse sent from the terminal 9 by an amount equivalent to an increase of the cable length is produced. |
