ENCODER

摘要

PURPOSE:To suppress and eliminate an edge business effectively by using a feedback means to correct a signal before coding to a signal of nearly same level between screens when the absolute value of a quantized error is a prescribed level or over in an encoder of a digital transmission system of a picture signal such as a television signal. CONSTITUTION:A subtractor 34 subtracts a correction value from a prediction value ei(n) and a quantizer 34 quantizes an output of the subtractor 34 to output an encoded code yi(n). A gate circuit 52 outputs a value -epsiloni(n) in the case of a prescribed level or over. A coefficient 54 multiplies alpha with an output gi(n) of the gate circuit 52 to output the result to a frame memory 56. The frame memory acts like a delay element by one frame and the output of the frame memory 56 is fed to the subtractor 34 as a correction value. The prescribed level is set to a value in which an edge business is a problem and the correction by the subtractor is not applied to a portion when the quantization error epsiloni(n) is below the prescribed level.