| 摘要 |
PURPOSE:To transmit a television signal for 2 channels in a narrow-band by obtaining a signal with an operation including the respective components of a mean signal and a 1/4-compressed difference signal at a receiving side. CONSTITUTION:When the television signal is made into B1, and signals before after B1 for one horizontal scanning period are made into A1 and C1, the signals at the receiving side, which are A1, B1, and C1, are respectively obtained by the operation including the respective components of (A1+C1)/2, (B1-A1)/2, and (B1-C1)/2. Consequently, a deterioration caused by the transmission characteristics of A1, B1 and C1 is averaged for each line, and the deterioration becomes inconspicuous. Signals A2, B2, and C2 are also the same. Since the difference signal is compressed to 1/4, the band is naturally enlarged to four- times. Since originally the frequency band of the difference signal does not influence at least a picture quality, the transmission can be executed with hardly deteriorating the picture quality when the frequency band for one channel exists. |
