DEMODULATOR FOR TELEVISION SIGNALS

摘要

PCT No. PCT/GB85/00021 Sec. 371 Date Sep. 17, 1985 Sec. 102(e) Date Sep. 17, 1985 PCT Filed Jan. 17, 1985 PCT Pub. No. WO85/03399 PCT Pub. Date Aug. 1, 1985.A demodulator for television signals includes a feedback loop which incorporates a delay for feeding back a first portion of a modulating signal to be compared with a following portion of the signal. This allows correlation of the modulating signals between the first portion of the signal and the following portion. Such correlation can be applied in feedback type demodulation such as phase-locked loops, to increase the threshold performance of the loop. The circuitry can be applied in normal demodulation circuits to effect a frequency tracking circuit allowing the use of a band pass filter with a narrower band than would be normally allowable.