| 摘要 |
An electrical circuit suitable for processing vertical detail signal information of a video signal is disclosed. The circuit includes an amplifier and an associated feedback impedance network for determining the circuit gain. Different values of feedback impedance are established in accordance with the operation of a signal responsive switching network included in the feedback network, to establish a signal amplitude transfer function wherein different amounts of signal gain are imparted to signals having amplitudes within prescribed ranges. Small amplitude signals subject to restoration are translated with a prescribed restoration gain. Moderate amplitude signals subject to enhancement (peaking) are translated by amplifying small amplitude excursions thereof with the restoration gain and by amplifying peak amplitude excursions with a gain greater than the restoration gain. Large amplitude signals subject to paring (amplitude reduction) are translated by amplifying small amplitude excursions thereof with the restoration gain, amplifying moderate amplitude excursions with a gain greater than the restoration gain, and amplifying peak amplitude excursions with a gain less than the restoration gain.
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