Ghost reduction circuit for a television receiver

摘要

A ghost reduction circuit for a television receiver incorporating a transversal filter comprises a memory for storing tap gains of tap gain amplifiers constituting part of the filter, a detector for detecting a ghost component as an error signal by comparing a vertical sync signal of the video signal passed through the filter with a reference sync signal, a circuit for converting a differentiated signal derived through differentiation of the error signal into a 3-state digital signal, and a subtractor for correcting the tap gain data stored in the memory in accordance with the digital signal, wherein the ghost component is substantially eliminated from the video signal inputted to the filter by controlling the gains of the tap gain amplifiers in accordance with the corrected memory data. The differentiated signal-to-digital signal conversion circuit includes first and second comparators having substantially the same threshold and connected in parallel between the input terminal and a subtracter, and an inverter amplifier connected between the input terminal and the second comparator. The outputs of the first and second comparators are subtracted from each other through the subtracter to produce the digital signal.