| 摘要 |
PURPOSE:To realize a miniature and simple processing circuit, by comparing a separated chroma signal with an attenuation control signal in terms of the absolute value and giving an AC-type clipping to attenuate the chroma signal level with a clipping value from the attenuation control signal then adding a luminant signal to the chroma signal. CONSTITUTION:A separated chroma signal C is compared with an attenuation control signal L supplied from a terminal 4 through a comparator 5 and in terms of the absolute value. Then a multiplexer 6 delivers the chroma signal itself in the case of ¦C¦<L. While in the case of ¦C¦>L, a clipping action is given with the signal sent from a complement generator 7 of a separating circuit 2, i.e., an attenuation control signal L used for the limiting value. Thus the same polarity as a chroma signal is secured for the attenuation control signal, and this attenuation control signal is delivered from the multiplexer 6. A digital chroma control signal subjected to attenuation control is added to a luminant signal Y at an adder 9 to be changed to a digital color video signal that subjected to chroma attenuation process. Thus a high-speed digital multipler is eliminated to realize an economical miniature chroma attenuating circuit with a simple constitution. |
