Closed-Caption DecoderDescriptionMN102H75K/F75K/85K/F85K LSI User Manual Panasonic Semiconductor Development Company227Panasonic9 Closed-Caption Decoder9.1 DescriptionThe MN102H75K/85K contains two identical closed-caption decoder circuits,CCD0 and CCD1. The decoders extract encoded captions from composite videosignals. Figure 9-1 provides a block diagram of the decoders, and section 9.3,“Functional Description,” on page 228, describes the circuit’s main blocks: theanalog-to-digital converter, clamping circuit, sync separator circuit, data slicer,controller, and sampling circuit. Note that this section describes CCD0, but alldescriptions apply to CCD1. Table 9-1 provides the pin names for each decoder.9.2 Block DiagramTable 9-1 Pins Used for CCD0 and CCD1Closed-Caption Decoder Pin NameCCD0 CVBS0 VREFHS CLH0 CLL0CCD1 CVBS1 VREFLS CLH0 CLL0Figure 9-1 Closed-Caption Decoder Block DiagramClamp ADC SlicingcircuitMax/mindetectorHSYNC separatorClampingcontrollerCRIfrequencydetectorData extractioncontrollerData extractor(sampling circuit)VSYNC separatorS/PRAMCPUCVBSData slicerSync separatorLow-pass filterSlice leveldetectorController
