| 摘要 |
PURPOSE:To prevent the generation of color irregularity even at a weak electric field, by switching an output of a digital filter inputted with a digital chroma signal represented in a binary code with an output of a weak electric field detecting circuit. CONSTITUTION:The digital chroma filter is constituted with m-stage of 1st order FIR digital fiber 5. Its transfer characteristic H(Z) is expressed as H(Z)=(1+ or - Z<-n1>)(1+ or -Z<-n2>)-(1+ or -Z<-nm>), where n,m are integral numbers. The digital chroma signal applied to an input terminal 6 is inputted in the binary code. In an example of execution, the signal is outputted to the input of a multiplexer 7 after passing through 4-stage of digital filters. The multiplexer 7 detects automatically an output passing through many stage numbers of the digital filters at a weak electric field with a weak electric field detecting circuit 8 detecting an AGC voltage of a television receiver, for example. |
