| 摘要 |
A circuit used to synchronize a television camera interconnected to a camera control unit through a cable having a plurality of conductive leads. An oscillator within the camera generates a rectangular-shaped pulse signal at line frequency, and applies this signal to a phase comparator in the control unit. The signal is transmitted from the oscillator through the cable. The phase comparator compares the rectangular-shaped pulse signal with a reference signal, and provides a control voltage which, in turn, is applied to the oscillator through a conductor within the cable. The signal derived from the oscillator may be in the form of closely spaced pulses of opposite polarity and short direction. The signal can also be in the form of a pair of pulse trains of opposite polarity and transmitted through the cable by a twisted pair of conductors.
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