A digital deemphasis circuit for the BTSC multichannel television standard includes a square-root extractor, a digital filter having the transfer function F(z)=(b-ac)/(z+a), where a, b and c are constants that determine the frequency response of the digital filter. The digital deemphasis circuit further includes a subcircuit that transforms the output signal from the square-root extractor into three quantities w1, w2, w3 that are applied as multiplicands to three multipliers to control the operation of the deemphasis circuit. |