| 摘要 |
PURPOSE:To speed up a processing and to decrease the circuit scale, by detecting information required for encoding and decoding with the hardware. CONSTITUTION:A composite logical circuit which is constituted with a programmable logic array 7 and an exclusive OR circuit 9 detects a changing picture element and encoded mode at the modified Hoffmann coding or the like and a changing picture element l1 of the vertical mode at the modified Reed decoding and a changing picture element b2 at the pass mode. Further, a horizontal mode detecting flag 5 is set at the modified Reed coding when the logical circuit detects changing picture element a1 and reset when a changing picture element a2 is detected. On the other hand, a b1 detecting flag 6 is set at the modified coding, when this logical circuit detects a picture element b1 and reset when the coding mode is detected. |
