TELEVISION SIGNAL CODING CIRCUIT

摘要

PURPOSE:To improve the picture quality in the case of using an information reduction means by setting a clamp level of an input video signal to a value able to be represented as a code of an output of a quantizer with most coarse accuracy in quantization of a PCM coding circuit. CONSTITUTION:A television signal is inputted to an input terminal 301 and a horizontal synchronizing part is clamped by a clamp circuit 302. In this case, the clamp level is set to a value able to be represented by a code of an output of a quantizer having the most coarse quantizing accuracy in PCM quantizing circuits 306-308 by a clamp level setting circuit 303. Then the signal is converted into a PCM signal in 8-bit by an A/D converter 304 and quantized by the circuits 306-308. Then the quantized signal is subjected to variable length coding by a variable length coding circuit 309 and smoothed by a buffer memory 310. The circuit 306 is an 8-bit quantizer, the circuit 307 is a 7-bit quantizer, and the circuit 308 is a 6-bit quantizer respectively. Any of the circuits 306-308 is selected by a selector 312 depending on the quantity of information detected by an information quantity counter 311.