| 摘要 |
In a picture block retransmission arrangement of a receiver in which a band-compression encoded picture block signal transmitted from a counterpart transmitter is decoded into a reproduced block signal comprising reproduced line signals representative of successive picture lines on a picture block, a checking arrangement (42, 43) checks whether each reproduced line signal is a correct or an incorrect line signal. A retransmission requesting assembly (44, 45, 15, 12) requests the transmitter to again transmit the picture block signal when the incorrect line signals are not less in number than a predetermined number. A substituting assembly (38, 41, 17, 46, 15) substitutes, for each incorrect line signal representative of a particular one of the picture lines, an again reproduced line signal decoded from one of the picture line signals that represents the particular picture line in the picture block signal retransmitted from the transmitter. In most cases, the picture block signal need not be further retransmitted even when the checking arrangement checks a substituted block signal wherein the again reproduced line signal is substituted for each incorrect line signal. The substituting assembly preferably comprises a storage memory (41) for storing, for a picture block reproduction of the picture block signal first transmitted from the transmitter, picture line reproductions of the picture line signals together with marks indicative of whether the respective picture line reproductions is correct or not.
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