| 摘要 |
A video signal decoder including a comb filter characterised by means for changing the operating mode of the filter progressively. Also, a video signal decoder including a comb filter characterised by means for adjusting continuously the degree of filtering performed by the filter. In one arrangement the decoder comprises an input filter and two signal multipliers wherein one of the multipliers is connected to receive a signal output by the input filter and the other multiplier is connected to receive a signal output by the comb filter wherein operation of the multipliers is mutually interdependent. In another arrangement, the decoder comprises an input filter, a subtraction circuit and a signal multiplier; the multiplier being connected to receive an output from the comb filter and multiply said output by variable factor so as to input a multiplied signal to said subtraction circuit; the subtraction circuit being connected to perform a subtraction between the multiplied signal and a signal output by the input filter, the subtraction circuit having an output which provides a chrominance signal. |
