Patent ID: 7499105

Claim:
A compensation circuit for frequency filters, particularly IF frequency filters, sound subcarrier filters or sound subcarrier traps of a video signal receiver, particularly a television signal receiver, the compensation circuit comprising: amplifier means for amplifying a signal, particularly a composite video signal, wherein the signal includes a first signal component having a first frequency and a second signal component having a second frequency, wherein the first frequency is lower than the second frequency; filtering means for filtering a frequency range within the signal, the filtering means having a non-linear, signal-dependent transfer function for amplifying the second signal component without amplifying the first component; detection means for detecting a characteristic of the first signal component before the signal is filtered by the filtering means; and variation means for varying the DC component of the signal in dependence upon said characteristic by producing a DC voltage and combining the DC voltage with the signal before the signal is filtered by the filtering means; wherein the non-linearity of the transfer function of the filtering means is at least partly compensated by variation of the DC component of the signal.