| 摘要 |
PURPOSE:To eliminate beat interference on the picture and enable application to various kind of scramble systems in satellite broadcast of TV, by using triangular wave relating to short horizontal scanning period as a diffusion signal. CONSTITUTION:Signals that control timing of duty, flat part, rise part and fall part of triangular wave and clock signals are supplied from an encoder 1 to a counter 2. The counter 2 counts clock signals basing on the control signal, and makes counting until specified timing at counting gradient corresponding to the duty, and outputs triangular wave of the shape of formed digital signal. The output is D/A converted 3, and the amplitide is adjusted by a variable attenuator 4 and sent out adding to a transmission signal by an adder 5. The receiving side removes diffusion signals from received signals and takes out transmission signals.
|
