| 摘要 |
PURPOSE:To reduce the disturbance onto an existing television receiver of the envelope detection system or the like by modulating a carrier subject to amplitude modulation and a carrier of orthogonal phase with a multiplexed signal, synthesizing the modulated signal at a lower level than the level of the carrier subject to amplitude modulation and sending the resulting signal. CONSTITUTION:The signal is separated into part of an electric signal corresponding to 4:3 and other part of the information of other side pattern, sent through other transmission line and the resulting signal is reproduced by demodulation and synthesis at a receiver. The signal inputted from a luminance signal input terminal 1 and a signal inputted from a color difference signal input terminal 2 are separated by separation circuits 3, 4, and the separated signal is expanded by time axis expansion circuits 6-9. Thus, the horizontal scanning period of only the pattern part with the aspect ratio of 4:3 is the same as the horizontal scanning period of the existing television broadcast system with 4:3 aspect ratio. Since the carrier modulated by the signal to be multiplexed is synthesized at a lower level, the disturbance onto the television receiver of the envelope detection system is reduced. |
