NON-LINEAR EMPHASIS CIRCUIT

摘要

A non-linear digital emphasis circuit for nonlinearly emphasizing a high frequency component of an input digital video signal in accordance with an amplitude of the digital video signal. This emphasis circuit comprises: a digital filter for emphasizing the high frequency component of the digital video signal; and a memory in which a data conversion table to non-linearly compress the amplitude of the digital video signal is written and to which the digital video signal is supplied as an address input. The respective polarities of the address input of the memory and of the readout output therefrom are inverted by a polarity inverter in accordance with the polarity of the digital video signal. With this emphasis circuit, an error of the frequency characteristic and time and temperature changes thereof are not caused and no adjustment of the characteristic is needed. Also, this circuit can be formed as an integrated circuit by utilizing only digital circuits.