| 摘要 |
PURPOSE:To make it possible to cancel a long delay time-ghost and make a unit small-size and economic, by digitizing video signals and subjecting them to the arithmetic processing to generate cancel signals which approximate the ghost wave. CONSTITUTION:Input video signal 1 is converted to a digital signal in converter 8 and is written in RAM-a 12 through DMA (direct memory access) controller 9, and meanwhile, MPU (microprocessor) 10 subjects signals stored in 12 to the arithmetic processing on a basis of information of polarity, a level and a delay time of ghost transmitted from ghost detector circuit 13 and generates a digital for cancelling ghost components and stores this signal in RAM-b 16, and this data is outputted from DMA controller 9 to D/A converter 14 synchronously with read operation after one horizontal synchronization passage. Next, the video signal which was converted to an analogue signal in converter 14 is subtracted from the original signal of input video signal 1 in 4 and has ghost cancelled and is inputted again from output terminal 6 to the video stage of a receiver. |
