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Hersteller: Mitsubishi Electronics Dateigröße: 3.06 mb Dateiname: Unterrichtssprache:

Although it’s not apparent from the Block Diagram, the NTSC Decoders, Component Switch ICs, and the Doubler circuitry are different. Note that all main picture sources, including the DTV Tuner, are processed by the Doubler circuitry. In the V21, 480p and DM signals only were processed by the Doubler circuitry when a display other than Standard format was selected, or when PIP/POP was activated. The new improved Color Management (ColorPerfectTM) circuitry is in the Doubler circuitry and it now processes all signal sources. Therefore all signals must pass through the Doubler. Two additional signal sources are shown in the Block Diagram, MLink (DVI) Input, and a Memory Card Reader located in the front of the TV. Also the diagram indicates that the Sub Picture source can only be from a NTSC source, an External Component Input or the DTV input. 5-2 PCB-TERMINAL Video Path Figure 5-1 illustrates the Video Signal Path on the PCBTERMINAL. The AV-Switch circuitry has not changed, IC2L00 and IC2K00 are the same ICs used in the V21 chassis. The 3DYC Motion Adaptive Come Filter provides a clean separation of luminance (Y) and chroma (C) signals. The Main and Sub Decoders are new, generic #TA12440AF. Their functions include: • Converting NTSC to YPbPr. • Sync Separation • Detecting signal format (480i, 480p, etc.) • Converting RGB to YPbPr. The Component Switch ICs are also new, generic # MM1519XQ. There are two Component Switch ICs on PCB-TERMINAL, and a third one on PCB-SIGNAL, not shown in Figure 5-1. IC2A00 selects the Main and Sub picture sources from: • Main Decoder output • External Comp-1 Input • External Comp-2 input IC2B00 selects the Main and Sub picture sources from: • The outputs of IC2A00 • The External DTV Inputs • The VGA Input The VGA Input cannot be selected as the Sub picture source. 5-3 The Sub picture signals from IC2B00 are directed to IC2G00, the Sub Decoder. Switch circuitry in IC2G00 selects Sub picture signals from IC2B00 or the AVSW( 2), IC2K00. As in previous chassis, the main and sub selected YPbPr signal are direct to the PCB-SIGNAL. PCB-SIGNAL Video Path Figure 5-2 shows the PCB-SIGNAL Video Signal Path. Sub picture signals from PCB-TERMINAL are routed directly to the Sub YPbPr inputs of PCB-DOUBLER. The main picture signals from PCB-TERMINAL are routed to COMP SW-3, IC2H01. IC2H01 selects the main signal from the PCB-TERMINAL main outputs, or the MLINK signal from the MLINK Decoder, or the RGB signal from the DM Module. The output of IC2H01 is applied to the Main Picture inputs to the Doubler circuit. Note that the OSD RGB signals from the DM Module are also directed the VCJ, IC2V01. On-Screen Display (OSD) signals are generated in the DM Module, and when the signal source is not the DM, OSD is inserted in the main picture in the VCJ. If the source is from the DM, the DTV Tuner or 1394 inputs, OSD insertion occurs in the DM module. The diagram also shows that Convergence OSD signals are applied to the VCJ and inserted in the VCJ. 5-4 The outputs of the Doubler circuit, ASIC-Y, ASIC-Pb and ASIC-Pr are directed to the VCJ. The signals are processed in the VCJ and CRT RGB drive signals are output at pins 64, 63, and 62. CRT Drive & Protect Circuitry Figure 5-3 shows the CRT Drive circuitry. Since it is the same as that in the V21, no explanation is necessary. The CRT Protection circuitry is also the same as the V21, but a review may be in order. When Q2W03 conducts, it turn On Q2W05, Q2W08 and Q2W11. The conduction of the three transistors removes RGB drive to the CRTS. The conduction of Q2W03 is controlled from two sources: 1) The BLANK-CRT command from the .PC, momentarily blanking the CRTs during channel or input selection changes. 2) The VBLNK line. The logic on the VBLNK line is controlled by Deflection Loss Detection circuitry. A High on VBLNK blanks the CRTs. The Deflection Loss Detection circuitry is discussed in detail in the Section on Deflection and HV. 5-5 Digital Signal Path The basic Digital Signal path was shown in Figure 5-2. Figure 5-4 shows the Digital Path in more detail. Digital signal sources are the DTV/AQM Tuner, 1394 Inputs and the front panel Card Reader. There are two 1394 inputs at the rear of the DM module. A third 1394 input is on the front of the Card Reader. The Card Reader serves as a feed through for the 1394 signals and does not process these signals at all. The I.F. signal from the DTV/QAM Tuner is directed to PCB-DEMODULATOR. The I.F. signal passes through two SAW filters, and two I.F. amp ICs, SF5200, IC5252, SF5201 and IC5253, in that order. The (+) and (-) I.F. signals from IC5253 are directed to pin 69 and 68 of the Demodulator, IC52A0. The output of the Demodulator is the Transport data stream used to modulate the carrier at the station. The Transport Data Stream (TODATA) is directed to the Digital Module. The signal is processed by the circuitry in the DM, and results in analog RGB signals output at pins 8, 4, and 6 of the VA connector. Signals from ...

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