Improvements in television.

摘要

A television transmitter includes in addition to a PAL or MAC encoder (14) a corresponding decoder (16) and a differencer (18) which compares the decoded signal and the full resolution input signal. The output of the differencer, representing coding/decoding impairments, is digitally coded (22) and inserted (30) in the line or field blanking intervals of the encoded signal as digital assistance information. A suitably-equipped receiver (20, Figure 2) can add the decoded difference information to the conventionally-decoded signal to improve picture quality.