Text preview for : Daewoo DTH-29U7 Chassis CP-830F.pdf part of Daewoo DTH-29U7 Daewoo DTH-29U7 Chassis CP-830F
Back to : Daewoo DTH-29U7 Chassis C | Home
S/M No.TCN830FEF0
CHASSIS : CP-830F
MODEL : DTH-29U7
OTC 2003
CP830F Service Manual
CONTENTS
DOCUMENT HISTORY 1 MAIN FEATURES 1.1 SPECIFICATIONS 1.1.1 GENERAL 1.1.2 EURO-SCART 1 (21 Pin) 1.1.3 EURO-SCART 2 (21 Pin) 1.2 CHANNEL/FREQUENCY TABLE 1.3 ATSS SORTING METHOD 1.3.1 GENERAL CASE 1.3.2 SPECIAL CASE 2 SAFETY INSTRUCTION 3 ALIGNMENT INSTRUCTIONS 3.1 MICROCONTROLLER CONFIGURATION : SERVICE MODE 3.2 SERVICE MODE NAVIGATION 3.3 MICROCONTROLLER CONFIGURATION : OPTION BITS 3.3.1 OPTION 1 3.3.2 OPTION 2 3.4 TV SET ALIGNMENT 3.4.1 LOCAL OSCILLATOR ALIGNMENT 3.4.2 G2 ALIGNMENT 3.4.3 WHITE BALANCE 3.4.4 FOCUS 3.4.5 VERTICAL GEOMETRY 3.4.6 HORIZONTAL PICTURE CENTRING 3.4.7 EAST / WEST CORRECTION 3.4.8 AGC 4 IC DESCRIPTION 4.1 TELETEXT DECODER WITH EMBEDDED 8-BIT CONTROLLER 4.1.1 BLOCK DIAGRAM OF THE SDA55XX 4.1.2 DESCRIPTION 4.1.3 IC MARKING AND VERSION 4.1.4 PINNING 4.2 VSP9412A - SCAN RATE CONVERTER INCLUDING MULTISTANDARD COLOUR DECODER 4.2.1 BLOCK DIAGRAM OF THE VSP9412A 4.2.2 DESCRIPTION 4.2.3 PINNING 4.3 DDP 3315C - DISPLAY AND DEFLECTION PROCESSOR 4.3.1 BLOCK DIAGRAM OF THE DDP 3315C 4.3.2 DESCRIPTION 4.3.3 PINNING 4.4 MSP341X MULTISTANDARD SOUND PROCESSOR 4.4.1 BASIC FEATURES OF THE MSP 341X 4.4.1.1 Demodulator & NICAM Decoder Section 4.4.1.2 DSP-Section (Audio Baseband Processing)
-1-
5 5 5 5 5 6 7 10 10 10 12 13 13 13 13 14 14 14 14 14 15 15 15 15 15 16 17 17 17 17 18 18 19 20 20 22 23 24 24 26 28 28 28 29
CP830F Service Manual
4.4.1.3 Analogue Section 4.4.1.4 NICAM & FM/AM-Mono 4.4.1.5 German 2-Carrier System (DUAL FM System) 4.5 TDA4470 - MULTISTANDARD VIDEO-IF AND QUASI PARALLEL SOUND PROCESSOR 4.5.1 DESCRIPTION 4.5.2 FEATURES 4.5.3 PINNING 4.5.4 BLOCK DIAGRAM 4.6 TDA894XJ STEREO AUDIO AMPLIFIER 4.6.1 FEATURES 4.7 TDA835XJ VERTICAL AMPLIFIER 4.7.1 TDA8357J 4.7.2 TDA8358J 4.8 TDA6107Q 4.9 24C16 - 16 KB EEPROM 4.10 STR - F6654 4.10.1 GENERAL DESCRIPTION 4.10.2 FEATURES 4.10.3 BLOCK DIAGRAM 4.10.4 PIN DESCRIPTION 4.10.5 CONTROL PART - ELECTRICAL CHARACTERISTICS 4.10.6 MOSFET ELECTRICAL CHARACTERISTICS 5 CP830 CHASSIS DESCRIPTION 5.1 BLOCK DIAGRAM 5.2 IF SECTION 5.2.1 BLOCK DIAGRAM 5.2.2 VISION IF AMPLIFIER 5.2.3 TUNER-AND VIF-AGC 5.2.4 FPLL, VCO AND AFC 5.2.5 VIDEO DEMODULATION AND AMPLIFIER 5.2.6 SOUND IF AMPLIFIER AND SIF-AGC 5.2.7 QUASI-PARALLEL-SOUND (QPS) MIXER 5.2.8 STANDARD SWITCH 5.2.9 L SWITCH 5.2.10 INTERNAL VOLTAGE STABILISER 5.3 VIDEO / RGB 51 5.3.1 FRONT END 5.3.1.1 CVBS Front-End 5.3.1.2 Input Selector 5.3.1.3 Signal Levels And Gain Control 5.3.1.4 Synchronization 5.3.1.5 Chroma Decoder 5.3.1.6 Luminance Processing 5.3.1.7 RGB Front-End 5.3.1.8 Signal Processing 5.3.1.8.1 Horizontal Prescaler 5.3.1.8.2 Noise Reduction 5.3.1.8.3 Noise Measurement 5.3.1.8.4 Operation Modes
-2-
29 29 29 32 32 32 32 33 34 34 35 35 37 39 40 41 41 41 41 42 42 43 44 44 45 45 46 46 46 47 47 47 47 47 47 47 47 48 48 48 48 48 48 48 48 49 49 49
CP830F Service Manual
5.3.1.8.5 Digital 656 Output 5.3.2 BACK END 5.3.2.1 Digital Input Interface 5.3.2.2 Horizontal Scaler 5.3.2.3 Luma Contrast and Brightness 5.3.2.4 Black Level Expander/Compressor (BLEC) 5.3.2.5 Luma Sharpness Enhancer (LSE) 5.3.2.6 Dynamic Peaking 5.3.2.7 Luma Transient Improvement (LTI) 5.3.2.8 Mixing of Dynamic Peaking and LTI 5.3.2.9 Chroma Transient Improvement 5.3.2.10 Analog Back End 5.3.2.11 Analog RGB Insertion 5.3.2.12 CRT Measurement and Control 5.3.2.13 Synchronization and Deflection 5.3.2.14 EHT Compensation 5.4 MICROCONTROLLER 5.4.1 MICROCONTROLLER FEATURES 5.4.2 ACQUISITION FEATURES 5.4.3 PORTS 5.4.4 -CONTROLLER I/O PIN CONFIGURATION AND FUNCTION TABLE 5.4.5 TUNING 5.4.6 AUTOMATIC PICTURE FORMAT SWITCHING 5.4.6.1 WSS Data 5.4.6.2 SCART Pin 8 Data (Slow Switching) 5.4.6.3 Picture Format Description 5.4.6.3.1 16:9 CRT 5.4.6.3.2 4:3 CRT 5.4.7 EXTERNAL SOURCE CONTROL LOGIC 5.4.8 OVER CURRENT PROTECTION 5.5 TELETEXT DISPLAY 5.6 SOUND PROCESSING 5.6.1 ANALOGUE SOUND IF - INPUT SECTION 5.6.2 QUADRATURE MIXERS 5.6.3 PHASE AND AM DISCRIMINATION 5.6.4 NICAM DECODER 5.6.5 DSP SECTION 5.6.6 SOUND MODE SWITCHING 5.7 SOUND AMPLIFICATION 5.7.1 POWER AMPLIFIER 5.7.2 MODE SELECTION 5.8 VERTICAL DEFLECTION 5.8.1 FLYBACK VOLTAGE 5.8.2 PROTECTION 5.8.3 GUARD CIRCUIT 5.8.4 DAMPING RESISTOR 5.8.5 EAST-WEST AMPLIFIER (TDA8358J ONLY) 5.9 POWER SUPPLY (STR F6654) 5.9.1 STR-F6654 GENERAL DESCRIPTION
-3-
49 49 49 49 49 49 50 50 50 50 50 51 51 51 52 52 52 52 53 53 53 54 54 54 55 55 55 56 57 58 58 59 59 59 59 60 60 60 60 60 60 61 61 61 61 61 61 61 61
CP830F Service Manual
5.9.2 POWER SUPPLY PRIMARY PART OPERATIONS 5.9.2.1 Start -up Circuit: VIN 5.9.2.2 STR-F6654 Oscillating Operation 5.9.2.3 STR-F6654 Protection Circuits 5.10 TV START-UP, TV NORMAL RUN AND STAND BY MODE OPERATIONS 5.10.1 TV START-UP OPERATIONS 5.10.1.1 Schematic Diagram For Start-Up Operations 5.10.1.2 TV Start-Up And Microcontroller Initialisation 5.10.2 TV NORMAL RUN AND STAND-BY MODE OPERATIONS 5.10.2.1 TV On Normal Run Mode 5.10.2.2 TV Set On Stand-By Mode 6 SERVICE PARTS LIST 6.1 DTH-29U7ZL 7 EXPLODED VIEW 7.1 DTH-29U7 61 62 63 64 65 65 65 65 67 67 70 72 72 88 88
8 PRINTED CIRCULT BOARD 8.1 MAIN PCB 8.2 CRT PCB 8.3 PFC PCB 9 SCHEMATIC DIAGRAM
93 93 94 95 96
-4-
CP830F Service Manual
DOCUMENT HISTORY VERSION V1.00 V1.01 DATE 18/11/02 22/11/02 COMMENTS Creation of document (Author M Hearn) for project CP830 100Hz TV. Reformatting of the document, plus insertion of Document History section
1 MAIN FEATURES 1.1 SPECIFICATIONS 1.1.1 GENERAL TV standard Colour system Sound system Power consumption Sound Output Power Speaker Teletext system Aerial input Channel coverage Tuning system Visual screen size Channel indication Program Selection Aux. terminal Tuner AV PAL - SECAM B/G D/K, PAL I/I, SECAM L/L PAL, SECAM PAL, SECAM, PAL 60, NTSC M, NTSC 4.43 NICAM B/G, I, D/K, L, FM 2Carrier B/G, D/K 29"(4:3) Real Flat :84W approx. 7W x 2 (at 60% mod, 10%THD) 12W 8 ohm x2 9 pages memory FASTEXT (FLOF or TOP) 75 ohm unbalanced Off-air channels, S-cable channels and hyperband frequency synthesiser tuning system 29" : 68cm On Screen Display 100 programmes EURO-SCART 1 : Audio / Video In and Out, R/G/B In, Slow and Fast switching. EURO-SCART 2 : Audio / Video In and Out, SVHS In. AV3 : Audio-Video Jack on front of cabinet. Headphone jack (3.5 mm) on front of cabinet SVHS3 (option) : Jack on front of cabinet ? sound input common with AV3. R-46G22
Remote Control Unit
1.1.2 EURO-SCART 1 (21 Pin) Pin Signal Description 1 Audio Output Right 2 Audio Input Right 3 Audio Output Left 4 Audio Earth 5 Blue Earth 6 Audio Input Left 7 Blue Input
Matching value 0.5 Vrms, Impedance < 1 k , ( RF 54% Mod ) 0.5 Vrms, Impedance > 10 k 0.5 Vrms, Impedance < 1 k , ( RF 54% Mod )
0.5 Vrms, Impedance > 10 k 0.7 Vpp 0.1V, Impedance 75
-5-
CP830F Service Manual
9 10 11 12 13 14 15 16 17 18 19 20 21 Green Earth N.C. Green Input N.C. Red Earth Blanking Earth Red Input Fast Switching Video Out Earth Video In Earth Video Output Video Input Common Earth
0.7 Vpp
0.1V, Impedance 75
0.7 Vpp 0.1V, Impedance 75 0 to 0.4V : Logic 0 , 1 to 3V : Logic 1 , Impedance 75
1 Vpp 1 Vpp
3dB, Impedance 75 3dB, Impedance 75
1.1.3 EURO-SCART 2 (21 Pin) Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Signal Description Audio Output Right Audio Input Right Audio Output Left Audio Earth Earth Audio Input Left N.C. N.C. N.C. N.C. N.C. N.C. Earth Earth Chroma Input N.C. Earth Video In Earth Video Output Video Input, Y In. Common Earth Matching value 0.5 Vrms, Impedance < 1 k ( RF 54% Mod ) 0.5 Vrms, Impedance > 10 k 0.5 Vrms, Impedance < 1 k , ( RF 54% Mod )
0.5 Vrms, Impedance > 10 k
3dB for a luminance signal of 1 Vpp
1 Vpp 1 Vpp
3dB, Impedance 75 3dB, Impedance 75
( Monitor output )
20 18 16 14 12 10 8 21 19 17 15 13 11 9 7
6 5
4 3
2 1
-6-
CP830F Service Manual
1.2 CHANNEL/FREQUENCY TABLE CHANNEL C01 C02 C03 C04 C05 C06 C07 C08 C09 C10 C11 C12 C13 C14 C15 C16 C17 C18 C19 C20 C21 C22 C23 C24 C25 C26 C27 C28 C29 C30 C31 C32 C33 C34 C35 C36 C37 C38 C39 C40 C41 C42 C43 C44 C45 EUROPE CCIR 46.25 48.25 55.25 62.25 175.25 182.25 189.25 196.25 203.25 210.25 217.25 224.25 53.75 82.25 183.75 192.25 201.25 471.25 479.25 487.25 495.25 503.25 511.25 519.25 527.25 535.25 543.25 551.25 559.25 567.25 575.25 583.25 591.25 599.25 607.25 615.25 623.25 631.25 639.25 647.25 655.25 663.25 FRANCE 55.75 (L ) 60.5 (L ) 63.75 (L ) 176.00 184.00 192.00 200.00 208.00 216.00 189.25 (LUX) 69.25 (L ) 76.25 (L ) 83.25 (L ) 90.25 97.25 471.25 479.25 487.25 495.25 503.25 511.25 519.25 527.25 535.25 543.25 551.25 559.25 567.25 575.25 583.25 591.25 599.25 607.25 615.25 623.25 631.25 639.25 647.25 655.25 663.25
-7-
GB(IRELAND) 45.75 53.75 61.75 175.25 183.25 191.25 199.25 207.25 215.25 223.25 231.25 239.25 247.25 49.75 57.75 65.75 77.75 85.75 471.25 479.25 487.25 495.25 503.25503.25 511.25 519.25 527.25 535.25 543.25 551.25 559.25 567.25 575.25 583.25 591.25 599.25 607.25 615.25 623.25 631.25 639.25 647.25 655.25 663.25
EAST OIRT 49.75 59.25 77.25 85.25 93.25 175.25 183.25 191.25 199.25 207.25 215.25 223.25 471.25 479.25 487.25 495.25 511.25 519.25 527.25 535.25 543.25 551.25 559.25 567.25 575.25 583.25 591.25 599.25 607.25 615.25 623.25 631.25 639.25 647.25 655.25 663.25
CP830F Service Manual
CHANNEL C46 C47 C48 C49 C50 C51 C52 C53 C54 C55 C56 C57 C58 C59 C60 C61 C62 C63 C64 C65 C66 C67 C68 C69 C70 C71 C72 C73 C74 C75 C76 C77 S01 S02 S03 S04 S05 S06 S07 S08 S09 S10 S11 S12 S13 S14 S15 S16 EUROPE CCIR 671.25 679.25 687.25 695.25 703.25 711.25 719.25 727.25 735.25 743.25 751.25 759.25 767.25 775.25 783.25 791.25 799.25 807.25 815.25 823.25 831.25 839.25 847.25 855.25 863.25 69.25 76.25 83.25 90.25 97.25 59.25 93.25 105.25 112.25 119.25 126.25 133.25 140.25 147.25 154.25 161.25 168.25 231.25 238.25 245.25 252.25 259.25 266.25 FRANCE 671.25 679.25 687.25 695.25 703.25 711.25 719.25 727.25 735.25 743.25 751.25 759.25 767.25 775.25 783.25 791.25 799.25 807.25 815.25 823.25 831.25 839.25 847.25 855.25 863.25 104.75 116.75 128.75 140.75 152.75 164.75 176.75 188.75 200.75 212.75 224.75 236.75 248.75 260.75 272.75 284.75
-8-
GB(IRELAND) 671.25 679.25 687.25 695.25 703.25 711.25 719.25 727.25 735.25 743.25 751.25 759.25 767.25 775.25 783.25 791.25 799.25 807.25 815.25 823.25 831.25 839.25 847.25 855.25 863.25 103.25 111.25 119.25 127.25 135.25 143.25 151.25 159.25 167.25 255.25 263.25 271.25 279.25
EAST OIRT 671.25 679.25 687.25 695.25 703.25 711.25 719.25 727.25 735.25 743.25 751.25 759.25 767.25 775.25 783.25 791.25 799.25 807.25 815.25 823.25 831.25 839.25 847.25 855.25 863.25 105.25 112.25 119.25 126.25 133.25 140.25 147.25 154.25 161.25 168.25 231.25 238.25 245.25 252.25 259.25 266.25
CP830F Service Manual
CHANNEL S17 S18 S19 S20 S21 S22 S23 S24 S25 S26 S27 S28 S29 S30 S31 S32 S33 S34 S35 S36 S37 S38 S39 S40 S41 EUROPE CCIR 273.25 280.25 287.25 294.25 303.25 311.25 319.25 327.25 335.25 343.25 351.25 359.25 367.25 375.25 383.25 391.25 399.25 407.25 415.25 423.25 431.25 439.25 447.25 455.25 463.25 FRANCE 296.75 136.00 160.00 303.25 311.25 319.25 327.25 335.25 343.25 351.25 359.25 367.25 375.25 383.25 391.25 399.25 407.25 415.25 423.25 431.25 439.25 447.25 455.25 463.25 GB(IRELAND) 287.25 295.25 303.25 311.25 319.25 327.25 335.25 343.25 351.25 359.25 367.25 375.25 383.25 391.25 399.25 407.25 415.25 423.25 431.25 439.25 447.25 455.25 463.25 EAST OIRT 273.25 280.25 287.25 294.25 303.25 311.25 319.25 327.25 335.25 343.25 351.25 359.25 367.25 375.25 383.25 391.25 399.25 407.25 415.25 423.25 431.25 439.25 447.25 455.25 463.25
-9-
CP830F Service Manual
1.3 ATSS SORTING METHOD The TV set sweeps all the TV bands from beginning of VHF to end of UHF. The TV controlling software for each program checks if a VPS CNI code is transmitted (this system exists for German, Swiss and Austrian transmissions). If no VPS CNI code is found, then the system checks if a CNI code is transmitted as part of the teletext transmission ( Packet 8/30 format 1 and format 2). If such a code ( VPS or teletext ) is found and if this code is in the ATSS list, the program is automatically named. If the transmission does not have VPS CNI, and no teletext service is available, then there is no possibility of the program being automatically named. The programs found are then sorted in 4 groups : Group I : It contains all the programs from the selected country and named by the TV controlling software. Within this group the sorting order is fixed by the ATSS list. Group II : It contains all the programs with a strong signal strength which are not listed in group I. Group III : It contains all the programs with a weak signal strength which are not listed in group I. Group IV : If two or more programs with the same code are found, only the strongest ( or if they have the same level the one with the lowest frequency) is listed in group I, II or III. The others are listed in group IV.
1.3.1 GENERAL CASE Program number 1 2 ... n n+1 ... m m+1 ... p p+1 ... q q+1 ... 99 0
1.3.2 SPECIAL CASE Program number 1 ... m m+1 ... p p+1 ... q q+1 ... 99 0 Group Group II Skip
Group Group I
Skip
Group III
Group II
Group IV
Group III
not used
Group IV
not used
Special case : Country selection = Others
-10-
CP830F Service Manual
Note : If two programs with the same name but a different code are found these two programs are listed in group I, II or III . The sorting order within group II, III, and IV is based on the channel frequency. The program with the lowest frequency is allocated the first rank in its group, and so forth until the last program of the group which has the highest frequency. Special case : France If France is selected, the TV controlling software first sweeps all TV bands with France system selected ( positive video modulation) and then a second time with Europe system selected ( negative video modulation). Special case : Switzerland If Switzerland is selected the TV controlling software first sweeps all TV bands with Europe system selected (negative video modulation) and then a second time with France system selected ( positive video modulation). Special case : GB Note for satellite receiver users : Before starting ATSS turn on your satellite receiver and tune to SKY NEWS . If GB is selected the TV controlling software seeks for programs only in UHF ( C21 to C70 ). The sorting order is : 1 - BBC1 2 - BBC2 3 - ITV 4 - CH4 5 - CH5 6 ? NEWS (Sky News) If two or more identical programs ( same name but different code e.g. BBC1 and BBC1 Scotland ) are found the following programs in the list will be shifted up. (1 - BBC1, 2 - BBC1, 3 BBC2, 4 - ITV, 5 - CH4, 6 - CH5, 7 - NEWS, ..) If one of the programs above is not found, the associated program number remains empty ( freq.=467.25 MHz - Skip selected - no name ? system = GB). example A : 1 - BBC1, 2 - BBC2, 3 - ITV, 4 - -----, 5 - CH5, 6 - NEWS, ... example B ( if 2 BBC1 found ) : 1 - BBC1, 2 - BBC1, 3 - BBC2, 4 - ITV, 5 - -----, 6 - CH5, 7 NEWS, ...
-11-
CP830F Service Manual
2 SAFETY INSTRUCTION WARNING: Only competent service personnel may carry out work involving the testing or repair of this equipment. X-RAY RADIATION PRECAUTION 1. Excessive high voltage can produce potentially hazardous X-RAY RADIATION. To avoid such hazards, the high voltage must not exceed the specified limit. The nominal value of the high voltage of this receiver is 25-26 KV (20 -21 ) or 26 KV (25 - 28 ) at max beam current. The high voltage must not, under any circumstances, exceed 27.5 KV (20 ), 29KV (21 ), 29.5 KV (25 ) or 30 KV (28 ). Each time a receiver requires servicing, the high voltage should be checked. It is important to use an accurate and reliable high voltage meter. 2. The only source of X-RAY Radiation in this TV receiver is the picture tube. For continued X-RAY RADIATION protection, the replacement tube must be exactly the same type tube as specified in the parts list. SAFETY PRECAUTION Potentials of high voltage are present when this receiver is operating. Operation of the receiver outside the cabinet or with the back board removed involves a shock hazard from the receiver. Servicing should not be attempted by anyone who is not thoroughly familiar with the precautions necessary when working on high voltage equipment. Discharge the high potential of the picture tube before handling the tube. The picture tube is highly evacuated and if broken, glass fragments will be violently expelled. If any Fuse in this TV receiver is blown, replace it with the FUSE specified in the Replacement Parts List. When replacing a high wattage resistor (metal oxide film resistor) in the circuit board, keep the resistor 10 mm away from circuit board. Keep wires away from high voltage or high temperature components. This receiver must operate under AC 230 volts, 5O Hz. NEVER connect to a DC supply or any other voltage or frequency. PRODUCT SAFETY NOTICE Many electrical and mechanical parts in this equipment have special safety-related characteristics. These characteristics are often passed unnoticed by a visual inspection and the X-RAY RADIATION protection afforded by them cannot necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are identified in this manual and its supplements, electrical components having such features are identified by designated symbol on the parts list. Before replacing any of these components, read the parts list in this manual carefully. The use of substitutes replacement parts which do not have the same safety characteristics as specified in the parts list may create X-RAY Radiation.
-12-
CP830F Service Manual
3 ALIGNMENT INSTRUCTIONS 3.1MICROCONTROLLER CONFIGURATION : SERVICE MODE To switch the TV set into service mode please see instruction below. 1 - Select PR. number 91 2 - Adjust sharpness to minimum and exit all menus. 3 - Within 2 seconds press the key sequence : RED - GREEN - menu The software version is displayed beside the word Service, e.g. SERVICE V1.00 . To exit SERVICE menu press menu key or Std By key. 3.2SERVICE MODE NAVIGATION Pr Up/Down remote keys : cycle through the service items available. Vol -/+ remote keys : Dec./Increment the values within range - Cycle trough option bits. OK key : Toggle bits in option byte Order 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Item HOR CEN RED GAIN GRN GAIN BLUE GAIN RED BIAS GRN BIAS AGC LEVEL G2 - SCREEN AFT OPTION1 OPTION2 PARABOLA HOR WIDTH CORNER T CORNER B HOR. PARAL V. LINEAR EW TRAPEZ S CORRECT VERT CENT VERT SIZE Default setting
3.3 MICROCONTROLLER CONFIGURATION : OPTION BITS There are two option bytes available (16 bits in all). These option bits are available from Service mode. First find the OPTION1 or OPTION2 control, and then use the Volume PLUS/MINUS buttons on the remote control keypad to locate the bits, and OK key to toggle them. The table below shows the two option bytes available;
-13-
CP830F Service Manual
3.3.1 OPTION 1 B7 TOP text OFF TOP text ON B6 FASTEXT (FLOF) OFF FASTEXT (FLOF) ON B5 TUBE 4:3 TUBE 16:9 B4 Headphone Volume/Balance control OFF Headphone Volume/Balance control ON B3 Dolby Virtual OFF Dolby Virtual ON B2 SVHS 3 disable SVHS 3 enable B1 B0 Tuner options 00 = Philips 01 = not used 10 = ALPS 11 = PARTSNIC (DW)
1
0
3.3.2 OPTION 2 B7 B6 B5 B4 B3 B2 B1 B0 1 Fixed to `0' JVC remote control AVL control OFF PICTURE TILT ON Program list enabled See table below. 0 Daewoo Remote control AVL control ON PICTURE TILT OFF Program list disabled
Beam Current Tube 0.95 1.00 4/3 - Super Flat, 16/9 Super Flat 1.05 1.10 1.20 1.25 4/3 - Real Flat, 16/9 Real Flat 1.30 1.35 All values modified are immediately memorised in eeprom. 3.4 TV SET ALIGNMENT 3.4.1 LOCAL OSCILLATOR ALIGNMENT Tune a colour bar pattern. The frequency of the signal carrier must be accurate ( Max +/- 10KHz deviation from the nominal channel frequency). Find AFT item in service mode. Adjust the coil L150 to bring the cursor to central position : 32. 3.4.2 G2 ALIGNMENT - Tune a colour bar pattern. - Find the G2 - SCREEN item in service mode. - Adjust screen volume ( on FBT ) to bring the cursor to central position : 32.
-14-
(mA) Nominal Max 1.10 1.15 1.20 1.25 1.35 1.40 1.45 1.50
B2 0 0 0 0 1 1 1 1
B1 0 0 1 1 0 0 1 1
B0 0 1 0 1 0 1 0 1
CP830F Service Manual
3.4.3 WHITE BALANCE - Select a dark picture and adjust RED BIAS and GRN BIAS to the desired colour temperature. - Select a bright picture and adjust RED, GRN and BLUE GAIN to the desired colour temperature. 3.4.4 FOCUS Adjust the Focus volume ( on FBT ) to have the best resolution on screen. 3.4.5 VERTICAL GEOMETRY Adjust V. LINEAR (linearity), S CORRECT (S. Correction), VERT SIZE (Vertical amplitude), VERT CENT (vertical centring) to compensate for vertical distortion.
3.4.6 HORIZONTAL PICTURE CENTRING Adjust HOR CEN (Horizontal centre) to have the picture in the centre of the screen. 3.4.7 EAST / WEST CORRECTION Adjust the PARABOLA, HOR WIDTH, CORNER, HOR PARAL, EW TRAPEZ, to compensate for geometrical distortion.
HOR PARAL
HOR WIDTH adjust for 93% overscan.
-15-
CP830F Service Manual
PARABOLA
CORNER B & CORNER T
EW TRAPEZ 3.4.8 AGC - Make sure option bits are correct for the tuner fitted on the chassis (See above how to change option bits). - Adjust the antenna signal level at 64 dB Vą 2 - Tune a colour bar pattern. - Find the AGC item in service mode. - Press the key OK on the remote keypad and wait until AGC level stabilise to the optimum value. - Alternatively, use Vol Up/Dwn keys to adjust manually to the desired Tuner Take Over Point (TOP).
-16-
CP830F Service Manual
4 IC DESCRIPTION 4.1 TELETEXT DECODER WITH EMBEDDED 8-BIT CONTROLLER TVText Pro is a 8-bit controller based on a enhanced 8051 core with embedded teletext, On screen Display and TV controller functions. 4.1.1 BLOCK DIAGRAM OF THE SDA55XX
4.1.2 DESCRIPTION The SDA 55xx is a single chip teletext decoder for decoding World System Teletext data as well as Video Programming System (VPS), Program Delivery Control (PDC), and Wide Screen Signalling (WSS) data used for PAL plus transmissions (line 23). The device provides an integrated general-purpose, fully 8051-compatible Microcontroller with television specific hardware features. The microcontroller has been enhanced to provide powerful features such as memory banking, data pointers and additional interrupts etc. The on-chip display unit for displaying Level 1.5 teletext data is also used for customer defined on-screen displays. Internal XRAM consists of 16 Kbytes. Device has an internal ROM of 128 Kbytes. The SDA 55xx supports a wide range of standards including PAL, NTSC and contains a digital slicer for VPS, WSS, PDC, TTX and Closed Caption, an accelerating acquisition hardware module, a display generator for Level 1.5 TTX data and powerful On screen Display capabilities based on parallel attributes, and Pixel oriented characters (DRCS). The 8-bit Microcontroller runs at 360 ns. cycle time (min.). Controller with dedicated hardware does most of the internal TTX acquisition processing, transfers data to/from external memory interface and receives/transmits data via I 2 C-firmware user-interface. The slicer combined with dedicated hardware stores TTX data in a VBI buffer of 1 Kilobyte. The Microcontroller firmware performs all the acquisition tasks (hamming-and parity-checks, page search
-17-
CP830F Service Manual
and evaluation of header control bits) once per field. Additionally, the firmware can provide high-end Teletext-features like Packet-26-handling, FLOF, TOP and list-pages. 4.1.3 IC MARKING AND VERSION Chassis CP830 IC marking OSD languages BULGARIAN, CZECH, GERMAN, DANISH, SPANISH, FRENCH, FINNISH, ENGLISH, GREEK, HUNGARIAN, ITALIAN, NORWEGIAN, DUTCH, POLISH, ROMANIAN, RUSSIAN, SWEDISH, SLOVAKIAN. ATSS countries Austria, Belgium, Switzerland, Czech Republic, Germany, Denmark, Spain, France, Finland, GB, Greece, Hungary, Italy, Ireland, Norway, Netherlands, Portugal, Poland, Sweden, Slovak Republic, Others Text
PAN-EUROPEAN LATIN, CYRILLIC, GREEK.
4.1.4 PSDIP 52-pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
PINNING Pin Name SCL SDA S/SW2 S/SW2 S/SW1 S/SW1 n.c. Reset Out VDD2.5 VSS VDD3.3 CVBS VDDA2.5 VSSA AFT AGC KEY OCP HS VS MODESW L/L IR INT Type IN/OUT IN/OUT IN IN IN IN OUT IN IN IN IN IN IN IN IN IN IN IN IN OUT OUT IN IN Short Description Software driven I2C bus Clock line Software driven I2C bus Data line Slow switching control for SCART 2. (See Microcontroller I/O pin configuration) Slow switching control for SCART 1. (See Microcontroller I/O pin configuration) Driven by controlling software to reset video IC s. Supply voltage 2.5V Ground (0V) Input/Output 3.3V CVBS input for the acquisition circuit Supply voltage for analog components Ground for analog components ADC input, AFT input ADC input, for AGC alignment only ADC input, local key sensing Switch Off the set when the voltage goes below a trigger level Horizontal sync for OSD/Txt synchronisation Vertical sync for OSD/Txt synchronisation High : Negative video modulation (B, G, D, K,I) Low : Positive video modulation (L / L ) High : L , Low : L Remote control signal input Interrupt input from audio processor
-18-
CP830F Service Manual
PSDIP 52-pin 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 Pin Name n.c. n.c. n.c. n.c. VSS VDD3.3 n.c. n.c. RESET XTAL2 XTAL1 VSSA VDDA2.5 R OUT G OUT B OUT BK OUT VDD2.5 VSS VDD3.3 n.c. n.c. n.c. AGC n.c. n.c. LED POWER Type Short Description
IN IN
Ground (0V) Input/Output 3.3V
IN OUT IN IN IN OUT OUT OUT OUT IN IN IN
A low level on this pin resets the device. Output of the inverting oscillator amplifier Input of the inverting oscillator amplifier Ground for analog components Supply voltage for analog components Red output Green output Blue output Blanking Supply voltage 2.5V Ground (0V) Input / Output 3.3V
OUT
Tuner TOP adjustment
OUT OUT
High : Green LED, Low : Red LED High : SMPS ON, Low : SMPS in stand by
4.2 VSP9412A - SCAN RATE CONVERTER INCLUDING MULTISTANDARD COLOUR DECODER The VSP 94x2A comprises all main functions of a digital featurebox in one monolithic IC. The device comprises a digital multistandard color decoder, a RGB interface with fast-blank capability (SCART), digital ITU656 input, scaling units including panorama, embedded DRAM for upconversion, picture improvements, temporal noise reduction as well as A/D and D/A converter.
-19-
CP830F Service Manual
4.2.1 BLOCK DIAGRAM OF THE VSP9412A
CVBS (Y/C) CVBS (OUT) R/Cr G/Y B/Cb FBL ITU 656 CLK 656
7
Data Acquisition
3 2 2 2 2 8
Input Processing Noise Reduction
Memory Mem. Controller Field Memory 4:2:2 Format
Source Select A/D Conversion Color Decoder Frontend Sync Soft Mix
Display Processing Hor. Scaling Panorama Peaking, CTI
Output Processing Display Sync
HOUT VOUT CLK27
D/A conversion Oversampling (9402/9432) Digital Output (9412/9442) B
Y Cr Cb Digital 656 CLK 656
Clock Generation
I2
C
SCL 20.25 MHz
SDA
cybso1
cybso2
cybso3
reset
h50 v50 v
xout xin
cybs1 cybs2 cybs3 cybs4 cybs5 cybs6 cybs7
Soruce Select (1)
ADC1 (2) CVBS Frontend ADC2 (2) ADCR (12) (4/4/6/7/8)
Y U,V
Clock generation (9/10/11)
free-running clocks Iine-locked clocks
Output Data Controller (55)
memory controller (39)
Output Sync Controller (40)
clkout vout hout
buffer
min1 gin1 bin1 fbt1 rin2 gin2 bin2 fbt2
Soruce Select (16)
ADCG (13) ADCB (14) ADCF (15)
RBB Frontend
Y U,V
Noise measurerrent (32)
Noise reduction (35/36/37/38)
eDRAM
data
CLKB36
656clk 656io0 656io1 656io2 656io3 656io4 656io5 656io6 656io7
PRIMUS VSP94x2A
ITO656 Decoder (41) Y DAC (52) Panorama Scaler (42/43/44/57) Peaking/DCTI/delzly (45/46/49/50) U DAC (53) V DAC (54) test-controller, memory hist PC interface (56) line locked or free-running 8 ITU656 Encoder (51)
data
buffer
Soft-mix (30)
Channel mix (31)
Sample tate Converter (33/34)
ayout auout avout
CLKF2PAD
CLKF20
656hinf 656vln clkf20
tclk
tms
adntd
scl
sda
4.2.2 DESCRIPTION Integrated Video Matrix switch - Up to seven CVBS inputs, up to two Y/C inputs, - Up to three CVBS outputs (even when Y/C input) - 9 bit amplitude resolution for CVBS, Y/C A/D converter - AGC (Automatic Gain Control)
-20-
CP830F Service Manual
Multi-standard colour decoder - PAL/NTSC/SECAM including all substandards - Automatic recognition of chroma standard - Only one crystal necessary for all standards RGB-FBL or YUV-H-V input - 8 bit amplitude resolution for RGB or YUV - 8 bit amplitude resolution for FBL or H ITU656 support - ITU656 output - DS656 output (double-scan 656like output) Noise reduction - Motion adaptive temporal noise reduction - Field-based temporal noise reduction for luminance and chrominance - Different motion detectors for luminance and chrominance or identical - Flexible programming of the temporal noise reduction parameters - Automatic measurement of the noise level Horizontal scaling of the 1fH signal - Split-screen possible with additional PiP or Text processor Flexible digital horizontal scaling of the 2fH signal (Not used in this chassis) - Scaling factors: 3, ... [2 pixel resolution], ..., 0.75 including 16:9 compatibility - 5 zone panorama generator Embedded memory - On-chip memory controller - Embedded DRAM core for field memory - SRAM for PAL/SECAM delay line Data format 4:2:2 Flexible clock and synchronisation concept - Horizontal line-locked or free-running mode - Vertical locked or free-running mode Scan-rate-conversion - Simple interlaced modes (100/120 Hz): AABB, AAAA, BBBB (9402A/9412A only) Flexible output sync controller - Flexible positioning of the output signal - Flexible programming of the output sync raster - Blank signal generation Signal manipulations - Still field - Insertion of coloured background - Windowing - Vertical chrominance shift for improved VCR picture quality Sharpness improvement (not used in this chassis) - Digital color transition improvement (DCTI) - Peaking (luminance) 1920 active pixel/per line in default configuration I2C-bus control (400 kHz) - selectable I C address 1.8V 5% and 3.3V 5% supply voltages P-MQFP-80 package
-21-
CP830F Service Manual
4.2.3 PINNING Pin 52 53 54 55 56 57 58 63 62 61 70 69 23 17 3 2 1 80 79 78 77 76 75 39 40 41 37 46 47 48 38 14 6 13 7 19 24 27 59 60 50 51 64 65 44 Name cvbs1 cvbs2 cvbs3 cvbs4 cvbs5 cvbs6 cvbs7 Cvbso1 Cvbso2 Cvbso3 Xin Xout Vout Hout i656i7 i656i6 i656i5 i656i4 i656i3 i656i2 i656i1 i656i0 i656iclk Rin1 Gin1 Bin1 Fbl1 Rin2 Gin2 Bin2 Fbl2 V Sda Scl Tms Adr/tdi Reset Clkout Vdd33c Vss33c Vddac1 Vssac1 Vddac2 Vssac2 Vdd33rgb I/O I I I I I I I O O O I O O O I I I I I I I I I I I I I I I I I I I/O I I I I O S S S S S S S Description CVBS input CVBS input CVBS input CVBS input or Y1 CVBS input or C1 CVBS input or Y2 CVBS input or C2 CVBS output 1 CVBS output 2 CVBS output 3 Crystal connection 1 Crystal connection 2 Vertical output Horizontal output 656 input (MSB) 656 input 656 input 656 input 656 input 656 input 656 input 656 input (LSB) 656 input clock R in 1 G in 1 B in 1 Fast Blank input 1 R in 2 G in 2 B in 2 Fast Blank input 2 Vertical pulse for RGB input I2C ?Bus data I2C ?Bus clock Test mode select I2C Address / test data in Reset input Output clock Supply voltage CVBS Supply voltage CVBS Supply voltage CVBS1 Supply voltage CVBS1 Supply voltage CVBS2 Supply voltage CVBS2 Supply voltage RGB
-22-
Remarks
Reset when low 27MHz 3.3V 0V 1.8V 0V 1.8V 0V 3.3V
CP830F Service Manual
Pin 45 42 43 35 36 68 66 67 5 4 28 29 34 33 72 73 12 11 25 26 71 18 20 32 31 30 22 21 16 15 10 9 74 8 49
Name Vss33rgb Vddargb Vssargb Vddafbl Vssafbl Vddapll Vddd1 Vssdl Vddd2 Vssd2 Vddd3 Vssd3 Vddd4 Vssd4 Vddp1 Vssp1 Vddp2 Vssp2 Vddp3 Vssp3 Tclk H50 V50 656io0 656io1 656io2 656io3 656io4 656io5 656io6 656io7 656clk 656hin/clkf20 656vin/blank Vssd5
I/O S S S S S S S S S S S S S S S S S S S S I O O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O I/O S
Description Supply voltage RGB Supply voltage for RGB Supply voltage for RGB Supply voltage for FBL Supply voltage for FBL Supply voltage for PLL Supply voltage for digital Supply voltage for digital Supply voltage for digital Supply voltage for digital Supply voltage for DRAM Supply voltage for digital Supply voltage for digital Supply voltage for digital Supply voltage for digital Supply voltage for digital Supply voltage for digital Supply voltage for digital Supply voltage for digital Supply voltage for digital Testclock Hout 50 Hz Vout 50 Hz Digital input / output Digital input / output Digital input / output Digital input / output Digital input / output Digital input / output Digital input / output Digital input / output Digital input / output clock Separate H input for 20.25 clock output Separate V input for 656 / BLANK output Supply voltage for digital
Remarks 0V 1.8V 0V 1.8V 0V 1.8V 1.8V digital 0V digital 1.8V digital 0V digital 1.8V digital 0V digital 1.8V digital 0V digital 3.3V pad 0V digital 3.3V pad 0V pad 3.3V pad 0V pad Connect to vss
LSB
0V
4.3 DDP 3315C - DISPLAY AND DEFLECTION PROCESSOR The DDP 3315C is a mixed-signal single-chip digital display and deflection processor, designed for high-quality backend applications in double scan and HDTV TV sets with 4:3 or 16:9 picture tubes. The interfaces qualify the IC to be combined with state of the art digital scan rate converters, as well as analog HDTV sources. The DDP 3315C contains the entire digital video component, deflection processing, and all analog interfaces to display the picture on a CRT.
-23-
CP830F Service Manual
4.3.1 BLOCK DIAGRAM OF THE DDP 3315C
SVM
R G B FBL
LLC 27/32/ 54 MHz
Clock Generator
SVM
analog RGBMatrix R G B
Pr Y Input Pb FBL
Y/ 656 YCrCb CrCb 4:2:2 / 4:1:1
Input Interface
Y Cb Cr
UpconVersion/ Scaling
Y Cb Cr
Y Picture Cb ImproveCr ment
R G B R G B
Matrix / PFG / NCE
Video DAC
R G B
Analog RGB Switch
R G B
Tube Control
R G B
Output Sense Input
SDA SCL
I2C Interface
EHT
V
Sawtooth / Parabola Generation
V EW H/V dynamic focus
V H&V EW
VERT+ VERT E/W
General purpose PWM
Sync Processing
V H
DisplayFreq. Doubling
H
H-Drive Generation
H
H
Security Unit HOUT
PWM 1/2
2H / 2V (1H / 1V)
FIFO Controlling
HFLB
DFVBL PWMV
VPROT HSAFETY
4.3.2 DESCRIPTION Video Processing - linear horizontal scaling (0.25 ... 4), as well as nonlinear horizontal scaling panorama vision - dynamic black level expander - luma sharpness enhancement by dynamic peaking and luma transient improvement (LTI) - color transient improvement (CTI) - programmable RGB matrix - black stretch, blue stretch, gamma correction via programmable Non-linear Colorspace Enhancer (NCE) on RGB - two analog double scan inputs with fast blank (one RGB and one RGB/YC r C b /YP r P b selectable) - average and peak beam current limiter - automatic picture tube adjustment (cutoff, drive) - histogram calculation Deflection Processing - scan velocity modulation output - digital EHT compensation for vertical / east-west - soft start/stop of horizontal-drive - vertical angle and bow correction - differential vertical outputs - vertical zoom via deflection adjustment - horizontal and vertical protection circuit
-24-
CP830F Service Manual
- horizontal frequency for VGA/SVGA/1080I - black switch off procedure - supports horizontal and vertical dynamic focus Miscellaneous - selectable ITU-R 601 4:1:1 / 4:2:2 YC r C b input at 27/32 MHz or double scan ITU-R 656 input at 54 MHz line-locked clock - crystal oscillator for horizontal safety - picture frame generator - hardware for simple 50/60 Hz to 100/120 Hz conversion (display frequency doubling) - PQFP80 package, 5 V analog and 3.3 V digital supply
IC architecture A clock generator converts different external line locked clock rates to a common internal sample rate of ~40 MHz, in order to provide a higher horizontal resolution. The input interface accepts ITU-R 601 at 27 or 32 MHz and ITU-R 656 with encoded or external sync at 54 MHz. The horizontal scaler is used for the scan rate conversion and for the nonlinear aspect ratio conversion as well. For the picture improvement, luma and chroma are processed separately. The luminance contrast ratio can be extended with a dynamic black level expander. In addition the frequency characteristic is improved by a transient improvement (LTI) and an adaptive dynamic peaking circuit. The peaking adapts to small AC amplitudes of high frequency parts, while large AC amplitudes are processed by the LTI. The chroma signal is enhanced with a transient improvement (CTI) with proper limitation to avoid wrong colours. The full programmable RGB matrix covers control of colour saturation and temperature. A digital white drive control is used to adjust the white balance and for the beam current limitation to prevent the CRT from over-load. A non-linear colorspace enhancer (NCE) for RGB gives full flexibility for any amplitude characteristic. High speed10-bit D/A converters are used to convert digital RGB to analog signals. Separate 9-bit D/A converters control brightness and cutoff. For picture tubes equipped with an appropriate yoke a scan velocity modulation (SVM) signal is calculated using a differentiated luminance signal.Two analog sources can be inserted in the main RGB, controlled by separate fastblank (FBL) signals. Contrast and brightness are adjusted separately from main RGB. One input is dedicated to RGB for on screen display (OSD). The second input is processed with an analog RGB matrix to insert YCbCr/YpbPr or RGB with control of colour saturation and programmable half contrast. The bandwidth of ~30MHz guarantees pixel based graphics to be displayed with full accuracy. All previously mentioned features are implemented in dedicated hardware. An integrated processor controls the horizontal and vertical deflection, tube measurement loops and beam current limitation. It is also used to calculate an amplitude histogram of the displayed image. The horizontal deflection is synchronized with two numeric phase-locked loops (PLL) to the incoming sync. One PLL generates the horizontal timing signals, e.g. blanking and key-clamping. The second PLL adjusts the phase of the horizontal drive pulse with a subpixel accuracy less than 1 ns. Vertical deflection and east/west correction waveforms are calculated as 6th order polynomials. This allows adjustment of an east/west parabola with trapezoidal, pincushion and an upper/lower corner correction (even for real flat CRT s), as well as a vertical sawtooth with linearity and S-correction. Scaling both waveforms, and limiting to fix amplitudes, performs a vertical zoom or compression of the displayed image. A field and line frequent control loop compensates picture content depending EHT distortions.
-25-
CP830F Service Manual
4.3.3 PINNING Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Pin Name Y6 Y7 656EN LLC2 HS VS FREQSEL CM1 CM0 VS2 XTAL2 XTAL1 NC GNDP VSUPP FIFORRD FIFORD FIFOWR FIFORWR PWM1 PWM2 PWMV HOUT VSTBY DFVBL HSYNC VSYNC NC ASG1 HFBL SAFETY VPROT RSW2 RSW1 SENSE GNDM VERT+ VERTEW I/O I I I I I I I I I I O I S S O O O O O O O O S O O O S I I I O I/O I S O O O Description Picture bus Luma Picture bus Luma (MSB) Enable 656 input mode System clock input Horizontal Sync Input Vertical Sync Input Selection of H-Drive Frequency Range Clock select 1 Clock select 0 Additionnal VSYNC input Analog Crystal Output Analog Crystal Input Ground, Output Pin Driver Supply voltage, Output Pin Driver FIFO Read Counter Reset FIFO Read Enable FIFO Write Enable FIFO Write Counter Reset I2C controlled DAC I2C controlled DAC / Tilt output I2C controlled DAC Horizontal drive output Standby supply voltage, Hout generation Dynamic focus blanking / horizontal DAF pulse Horizontal sync output Vertical sync output Analog Shield Ground Horizontal flyback input Safety input Vertical protection input Range Switch2, measurement ADC Range Switch1, measurement ADC Sense ADC input Ground, MADC input Differential Vertical Sawtooth Output Differential Vertical Sawtooth Output East / West Correction Output
-26-
Remarks
CP830F Service Manual
Pin No. 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80
Pin Name NC SVM ROUT GOUT BUT GNDO XREF VSUPO VRD/BCS AGND FBLIN1 RIN1 GIN1 BIN1 FBLIN2 RIN2 / PR GIN2 / Y BIN2/ PB ASG2 HCS NC TEST RESQ SCL SDA C0 C1 C2 C3 C4 C5 C6 C7 VSUPD GNDD Y0 Y1 Y2 Y3 Y4 Y5
I/O O O O O S I S I S I I I I I I I I S I I I I/O I/O I I I I I I I I S S I I I I I I
Description Scan Velocity Modulator Analog Output Red Analog Output Green Analog Output Blue Ground, analog Back End Reference Input for RGB DAC s Supply voltage, Analog Back End DAC Reference, Beam current safety Analog Ground for Analog Matrix Fast Blank1input Analog Red1input Analog Green1 input Analog Blue1input Fast Blank2 input Analog Red2 input / PR Input Analog Green2 input / Y Input Analog Blue2 input / PB Input Analog Shield Ground Half Contrast
Remarks
Reset Input, active low I2C Bus clock I2C Bus data Picture Bus Chroma (LSB) Picture Bus Chroma Picture Bus Chroma Picture Bus Chroma Picture Bus Chroma Picture Bus Chroma Picture Bus Chroma Picture Bus Chroma (MSB) Supply voltage, Digital Circuitry Ground, Digital Circuitry Picture Bus Luma (LSB) Picture Bus Luma Picture Bus Luma Picture Bus Luma Picture Bus Luma Picture Bus Luma
-27-
CP830F Service Manual
4.4 MSP341X MULTISTANDARD SOUND PROCESSOR The MSP 341x is designed as a single-chip Multistandard Sound Processor for applications in analogue and digital TV sets, video recorders, and PC cards. The MSP3411 has all functions of MSP3410 with the addition of a virtual surround sound features. Surround sound can be reproduced to a certain extent with two loudspeakers. The MSP3411 includes virtualizer algorithm 3D Panorama which has been approved by the Dolby laboratories for compliance with the Virtual Dolby Surround technology. In addition, the MSP3411 includes Micronas Panorama algorithm. MSP 341x features: sound IF input No external filters required Stereo baseband input via integrated AD converters Two pairs of DA converters Two carrier FM or NICAM processing AVC : Automatic Volume Correction Bass, treble, volume processing Full SCART in/out matrix without restrictions Improved FM-identification Demodulator short programming Auto-detection for terrestrial TV - sound standards Precise bit-error rate indication Automatic switching from NICAM to FM/AM or vice versa Improved NICAM synchronisation algorithm Improved carrier mute algorithm Improved AM-demodulation Reduction of necessary controlling Less external components 4.4.1 BASIC FEATURES OF THE MSP 341X 4.4.1.1 Demodulator & NICAM Decoder Section The MSP 341x is designed to simultaneously perform digital demodulation and decoding of NICAM-coded TV stereo sound, as well as demodulation of FM or AM mono TV sound. Alternatively, two carrier FM systems according to the German terrestrial specs can be processed with the MSP 341x. The MSP 341x facilitates profitable multistandard capability, offering the following advantages: Automatic Gain Control (AGC) for analogue input: input range: 0.10 - 3 Vpp integrated A/D converter for sound-IF input all demodulation and filtering is performed on chip and is individually programmable easy realisation of all digital NICAM standards (B/G, I, L and D/K) FM-demodulation of all terrestrial standards (include identification decoding) no external filter hardware is required only one crystal clock (18.432 MHz) is necessary high deviation FM-mono mode (max. deviation: approx. 360 kHz)
-28-
CP830F Service Manual
4.4.1.2 DSP-Section (Audio Baseband Processing) flexible selection of audio sources to be processed performance of terrestrial de-emphasise systems (FM, NICAM) digitally performed FM-identification decoding and de-matrixing digital baseband processing: volume, bass, treble simple controlling of volume, bass, treble 4.4.1.3 Analogue Section two selectable analogue pairs of audio baseband input (= two SCART inputs) input level: <2 V RMS, input impedance: >25 one selectable analogue mono input (i.e. AM sound): Not used in this chassis two high-quality A/D converters, S/N-Ratio: >85 dB 20 Hz to 20 kHz bandwidth for SCART-to-SCART copy facilities loudspeaker: one pair of four-fold oversampled D/A converters. Output level per channel: max. 1.4 VRMS output resistance: max. 5 k . S/N-ratio: >85 dB at maximum volume max. noise voltage in mute mode: < 10 (BW: 20 Hz... 16 kHz) one pair of four-fold oversampled D/A converters supplying a pair of SCART-outputs. Output level per channel: max. 2 V RMS, output resistance: max. 0.5 k , S/N-Ratio: >85 dB (20 Hz... 16 kHz) 4.4.1.4 NICAM & FM/AM-Mono According to the British, Scandinavian, Spanish, and French TV-standards, high-quality stereo sound is transmitted digitally. The systems allow two high-quality digital sound channels to be added to the already existing FM/AM-channel. The sound coding follows the format of the socalled Near Instantaneous Companding System (NICAM 728). Transmission is performed using Differential Quadrature Phase Shift Keying (DQPSK. Table below offers an overview of the modulation parameters. In the case of NICAM/FM (AM) mode, there are three different audio channels available: NICAM A, NICAM B, and FM/AM-mono. NICAM A and B may belong either to a stereo or to a dual language transmission. Information about operation mode and about the quality of the NICAM signal can be read by the controlling software via the control bus. In the case of low quality (high bit error rate), the controlling software may decide to switch to the analogue FM/AM-mono sound. Alternatively, an automatic NICAM-FM/AM switching may be applied. 4.4.1.5 German 2-Carrier System (DUAL FM System) Since September 1981, stereo and dual sound programs have been transmitted in Germany using the 2-carrier system. Sound transmission consists of the already existing first sound carrier and a second sound carrier additionally containing an identification signal. More details of this standard are given in Tables below. For D/K very similar system is used. TV standards TV system B/G B/G L I D/K Position of sound carrier (MHz) 5.5 / 5.7421875 5.5 / 5.85 6.5 / 5.85 6.0 / 6.552 6.5 / 6.2578125 D/K1 6.5 / 6.7421875 D/K2 6.5 / 5.85 D/K-NICAM Sound modulation FM Stereo FM-Mono / NICAM AM - Mono / NICAM FM-Mono / NICAM FM Stereo FM-Mono / NICAM
-29-
Colour system PAL PAL SECAM-L PAL SECAMEast
Country GERMANY Scandinavia, Spain France UK USSR Hungary
CP830F Service Manual
Sound IF 1 ADC Sound IF 2
Demodulator
Preprocessing
Loudspeaker Sound Processing
Loudspeaker DAC Subwoofer
Source Select
I2S1 I2S2 SCART 1 SCART 2 SCART 3 SCART 4 MONO
Prescale
Headphone Sound Processing
DAC
Headphone I2S
DAC DSP SCART Input Select SCART1 ADC Prescale DAC SCART Output Select SCART2
Architecture of MSP341x
Pin connections and short description Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Pin Name NC NC NC INT MUTE ADR_SEL STANDBYQ NC I2C_CL I2C_DA NC NC NC NC NC NC NC DVSUP DVSS NC NC Type Short description Not Connected Not Connected Not Connected Interrupt out Mute out I2C bus Address select Standby ( Low-active) Not Connected I2C Clock I2C data Not Connected Not Connected Not Connected Not Connected Not Connected Not Connected Not Connected Digital power supply +5V Digital Ground Not Connected Not Connected
-30-
Out Out In In In / Out In / Out
CP830F Service Manual
Pin No. 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64
Pin Name NC NC RESETQ DACA_R DACA_L VREF2 DACM_R DACM_L NC NC NC SC2_OUT_R SC2_OUT_L VREF1 SC1_OUT_R SC1_OUT_L CAPL_A AHVSUP CAPL_M AHVSS AGNDC NC NC NC SC3_IN_L SC3_IN_R ASG2 SC2_IN_L SC2_IN_R ASG1 SC1_IN_L SC1_IN_R VREFTOP MONO_IN AVSS AVSUP ANA_IN1+ ANA_IN1NC TESTEN XTAL_IN XTAL_OUT NC
Type
In Out Out Out Out
Out Out Out Out
In In In In In In In
In In In In Out
Short description Not Connected Not Connected Power-On-reset Headphone out right Headphone out left Reference ground 2 high voltage part Loudspeaker out Right Loudspeaker out Left Not Connected Not Connected Not Connected Scart output 2 right Scart output 2 left Reference ground 1 high voltage part Scart output 1, right Scart output 1, left Volume capacitor AUX Analog power supply 8.0V Volume capacitor MAIN Analog ground Analog reference voltage high voltage part Not Connected Not Connected Not Connected Scart input 3 in, left Scart input 3 in, right Analog Shield Ground 2 Scart input 2 in, left Scart input 2 in, right Analog Shield Ground 1 Scart input 1 in, left Scart input 1 in, right Reference voltage IF A/D converter Mono input Analog ground Analog power supply IF input 1 IF common Not Connected Test pin Crystal oscillator Crystal oscillator Test pin
-31-
CP830F Service Manual
4.5 TDA4470 - MULTISTANDARD VIDEO-IF AND QUASI PARALLEL SOUND PROCESSOR 4.5.1 DESCRIPTION The TDA4470 is an integrated bipolar circuit for multi-standard video/sound IF (VIF/SIF) signal processing in TV/VCR and multimedia applications. The circuit processes all TV video IF signals with negative modulation (e.g., B/G standard), positive modulation (e.g., L standard) and the AM, FM/NICAM sound IF signals. 4.5.2 FEATURES - 5 V supply voltage; low power consumption. - Active carrier generation by FPLL principle (frequency-phase-locked-loop) for true synchronous demodulation. - Very linear video demodulation, good pulse response and excellent intermodulation figures. - VCO circuit operates at picture carrier frequency, the VCO frequency is switchable for L -mode - Alignment-free AFC without external reference circuit, polarity of the AFC curve is switchable. - VIF-AGC for negative modulated signals (peak sync. detection) and for positive modulation (peak white/black level detector). - Tuner AGC with adjustable take over point. - Alignment-free quasi parallel sound (QPS) mixer for FM/NICAM sound IF signals. - Intercarrier output signal is gain controlled (necessary for digital sound processing). - Complete alignment-free AM demodulator with gain controlled AF output. - Separate SIF-AGC with average detection - Two independent SIF inputs - Parallel operation of the AM demodulator and QPS mixer (for NICAM-L stereo sound). 4.5.3 PINNING Pin 1, 2 3 4, 9, 16 5 6, 7 8 10 11 12 13 14 15 17 18 19 20, 21 22 23 24 25 26 27, 28 Symbol Vi, SIF1 VSW GND VAGC Vi, VIF CAGC RTOP Itun VO, VID VSW VSW Cbl Cref LF VSW VVCO VAFC VS VO, FM VO, AM Rcomp Vi, SIF2 Function SIF1 input (symmetrical) Input selector switch Ground SIF - AGC (time constant) VIF input (symmetrical) VIF - AGC (time constant) Take Over Point, tuner AGC Tuner AGC output current Video output Standard switch L switch Black level capacitor Internal reference voltage Loop Filter AFC switch VCO circuit AFC output Supply voltage Intercarrier output AF output - AM sound Offset compensation SIF2 input (symmetrical)
-32-
CP830F Service Manual
4.5.4 BLOCK DIAGRAM
Offset comp. (optional) Loop filter l' switch VCO
26
18
20
21
14
FPLL
VCO + phase shift
Control 19 AFC 22
AFC switch AFC
6 VIF CAGC 7
VIF amp Video Video det.
8 AGC (VIF) 13 Standard
15 CBL Tuner 11 10 Take over point SIF 2 SIF input switch
Standard switch
23 Tuner AGC FM det. Supply 17 Cref 24
V
27 28 SIF amp 3
Intercarrier (FM/NICAM)
1 SIF 1 2 AGC (SIF) AM det. 25 AF (AM)
5 CAGC
4,9,16
-33-
CP830F Service Manual
4.6 TDA894XJ STEREO AUDIO AMPLIFIER The TDA 8944J ( TDA 8946J ) is a dual-channel audio power amplifier with an output power of 2 x 7 W ( 2 x 15 W ) at an 8 ? load and a 12 V supply. The circuit contains two Bridges Tied Load (BTL) amplifiers with an all-NPN output stage and standby/mute logic. The TDA8944J comes in a 17-pin DIL power package. 4.6.1 FEATURES Few external components Fixed gain Standby and mute mode No on/off switching plops low standby current High supply voltage ripple rejection Outputs short-circuit protected to ground, supply and across the load Thermally protected Pin description Pin 1 2 3 4 5 6 7 8 9 10 11 12 Symbol OUT1GND1 Vcc1 OUT1+ n.c. IN1+ n.c. IN1IN2MODE SVR IN2+ Description negative loudspeaker terminal 1 ground channel 1 supply voltage channel 1 positive loudspeaker terminal 1 not connected positive input1 not connected negative input1 negative input2 mode selection input half supply voltage decoupling (ripple rejection) positive input2
OUT1GND1 Vcc1 OUT1+ n.c. IN1+ n.c. IN1IN2MODE SVR IN2+ n.c OUT2+ GND2 Vcc2 OUT21 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
TDA8944J
-34-
CP830F Service Manual
VCC1 3
VCC2 16 1
OUT1-
IN1IN1+
8 6 4 OUT1+
TDA8944J
17 IN2IN2+ 9 12 14 VCC MODE SVR 10 11 STANDBY/ MUTE LOGIC SHORT CIRCUIT AND TEMPERATURE PROTECTION 2 GND1 15 MBK933 GND2 OUT2+ OUT2-
Block Diagram TDA8944J
4.7 TDA835XJ VERTICAL AMPLIFIER The TDA835xJ are power circuit for use in 90 and 110 colour deflection systems for field frequencies of 25 to 200Hz and 16/9 picture tubes. The circuit provides a DC driven vertical deflection output circuit, operating as a highly efficient class G system. Due to the full bridge output circuit the deflection coils can be DC coupled. The IC is constructed in a Low Voltage DMOS process that combines Bipolar, CMOS and DMOS devices. MOS transistors are used in the output stage because of the absence of second breakdown.
4.7.1 TDA8357J Features : Few external components Highly efficient fully DC-coupled vertical output bridge circuit Short rise and fall time of the vertical flyback switch Guard circuit Temperature (thermal) protection High EMC because of common mode inputs
-35-
CP830F Service Manual
Vi(pos) Vi(neg) Vp VcB GND Vflb VcA Vo(guard) VM
1 2 3 4 5 6 7 8 9
TDA8357J
Pinning Pin 1 2 3 4 5 6 7 8 9 Symbol Vi(pos) Vi(neg) Vp VOB GND Vflb VOA VO(guard) VM Description input voltage (positive) input voltage (negative) supply voltage output voltage B ground flyback supply voltage output voltage A guard output voltage input measuring resistor
-36-
CP830F Service Manual
V0(guard) 8 guard
Vp 3
Vflb 6
7 +Vi(diff) Vi(sb) -Vi(diff) Vi(neg) Vi(neg) +Vi(diff) Vi(sb) -Vi(diff) 2 Vi(pos) 1
VoA
input/ feedback
9
VM
4 VoB
5 GND GNDEW
4.7.2 TDA8358J An East-West output stage is provided that is able to sink current from the diode modulator circuit. Features : Few external components Highly efficient fully DC-coupled vertical output bridge circuit Short rise and fall time of the vertical flyback switch Guard circuit Temperature (thermal) protection High EMC because of common mode inputs East-West output stage
-37-
CP830F Service Manual
Vi(pos) Vi(neg) Vp VcB VEw GNDv GNDEw VoEw Vflb VoA
1 2 3 4 5 6 7 8 9 10
TDA8357J
Vo(guard) 11 VM 12
lcomp
13
Icomp 13 comp
V0(guard) 11 guard
Vp 3
Vflb 9
M5 D2 M2 D1 10 VoA +Vi(diff) Vi(sb) -Vi(diff) Vi(neg) Vi(neg) +Vi(diff) Vi(sb) -Vi(diff) 2 M1 4 VoB M3 8 VoEW Vi(pos) 1 input/ feedback M4 12 VM D3
IiEW(top) IiEW(bot)
5 6 GNDV
M6 7
GNDEW
-38-
CP830F Service Manual
4.8 TDA6107Q The TDA6107Q includes three video output amplifiers in one plastic DIL-Bent-SIL 9-pin medium power package, using high voltage DMOS technology, and is intended to drive the three cathodes of a colour CRT directly. To obtain maximum performance, the amplifier should be used with black-current control. Features Typical bandwidth of 5.5 MHz for an output signal of 60 Vpp High slew rate of 900V/ No external components required Very simple application Single supply voltage of 200V Internal reference voltage of 2.5 V Fixed gain of 50. Black-current stabilisation (BCS) circuit Thermal protection Pin description Pin 1 2 3 4 5 6 7 8 9 Symbol Vi(1) Vi(2) Vi(3) GND Iom VDD VOC(3) VOC(2) VOC(1) Description inverting input 1 inverting input 2 inverting input 3 ground (fin) black current measurement output supply voltage cathode output 3 cathode output 2 cathode output 1
Vi(1) Vi(2) Vi(3) GND Iom VDD Voc(3) Voc(2) Voc(1) 1 2 3 4 5 6 7 8 9
TDA6107Q
-39-
CP830F Service Manual
Block diagram TDA6107Q 4.9 24C16 - 16 KB EEPROM Features : 16 Kbit serial I2C bus EEPROM Single supply voltage : 4.5 V to 5.5 V 1 Million Erase/Write cycles (minimum) 40 year data retention (minimum) Pin description Pin No. Name Description 1, 2, 3 E0, E1, E2 Device address ? not used 5 SDA Serial Data/Address Input/Output 6 SCL Serial clock 7 WC Write control 8 Vcc Supply voltage 4 Vss Ground The memory device is compatible with the I2C memory standard. This is a two wire serial interface that uses a bidirectional data bus and serial clock. The memory carries a built-in 4-bit unique device type identifier code (1010) in accordance with the I2C bus definition. Serial Clock (SCL) The SCL input is used to strobe all data in and out of the memory. Serial Data (SDA) The SDA pin is bi-directional, and is used to transfer data in or out of the memory
-40-
CP830F Service Manual
4.10 STR - F6654 4.10.1 GENERAL DESCRIPTION The STR-F6654 is an hybrid IC with a build-in MOSFET and control IC, designed for flyback converter type switch mode power supply applications. 4.10.2 FEATURES Small SIP fully isolated moulded 5 pins package Many protection functions : Pulse-by-pulse overcurrent protection (OCP) Overvoltage protection with latch mode (OVP) Thermal protection with latch mode (TSD) 4.10.3 BLOCK DIAGRAM
-41-
CP830F Service Manual
4.10.4 PIN DESCRIPTION PIN NAME 1 Overcurrent feedback 2 3 4 5 Source Drain Supply Ground SYMBOL O.C. P/E.B. S D VIN GND DESCRIPTION Input of over current detection signal and feedback signal Mosfet source Mosfet drain Input of power supply for control circuit Ground
4.10.5 CONTROL PART - ELECTRICAL CHARACTERISTICS DESCRIPTION Operation start voltage Operation stop voltage Circuit current in operation Circ. current in non-operation Maximum off time Minimum time for input of quaxi resonant signals Minimum off time O.C.P./F.B. terminal threshold voltage 1 O.C.P./F.B. terminal threshold voltage 2 O.C.P./F.B. terminal extraction current OVP operation voltage Latch circuit sustaining voltage Latch circuit release voltage Thermal shutdown operating temperature IC PIN NUMBER 4-5 4-5 4-5 4-5 1-5 1-5 1-5 1-2 4-5 4-5 4-5 SYMBOL VIN (on) VIN (off) IIN (on) IIN (off) TOFF (max) TTH (2) TOFF (min) VTH (1) VTH (2) IOCP/FB VIN (OVP) IIN (H) VIN (Loff) TJ (TSD) RATING TYPE 16 10 0.73 1.45 1.35 22.5 UNIT V V mA SEC SEC SEC V V mA V
MIN. 14.4 9 45 0.68 1.3 1.2 20.5 6.6 140
MAX 17.6 111 30 100 55 1.0 1.5 0.78 1.6 1.5 24.5 400 8.4 -
V 0C
-42-
CP830F Service Manual
4.10.6 MOSFET ELECTRICAL CHARACTERISTICS IC PIN NUMBER Drain-to-source break down voltage 3-2 Drain leakage current 3-2 On-resistance 3-2 Switching time 3-2 Thermal resistance RATING TYPE -
DESCRIPTION
SYMBOL VDSS IDSS RDS (on) tf OCH - F
MIN. 650 -
MAX 300 1.95 250 0.95
UNIT V
noec 0C/W
-43-
CP830F Service Manual
5 CP830 CHASSIS DESCRIPTION 5.1 BLOCK DIAGRAM
-44-
CP830F Service Manual
5.2 IF SECTION 5.2.1 BLOCK DIAGRAM
-45-
CP830F Service Manual
5.2.2 VISION IF AMPLIFIER The video IF signal (VIF) is fed through a SAW filter to the differential input (Pin 6-7) of the VIF amplifier. This amplifier consists of three AC-coupled amplifier stages. Each differential amplifier is gain controlled by the automatic gain control (VIF-AGC). The output signal of the VIF amplifier is applied to the FPLL carrier generation and the video demodulator. SAW filters Ref. K3953M Standard B/G - D/K - I - L/L Features IF filter for video application TV IF filter with Nyquist slopes at 33.9 MHz and 38.9 MHz Constant group delay IF filter for audio application TV IF audio filter with two channels Channel 1 (L ) with one pass band for sound carrier at 40.40 MHz Channel 2 ( L, D/K, I, B/G) with one pass band for sound carriers between 32.40 MHz and 33.40 MHz
K9650M
B/G - D/K - I - L/L
5.2.3 TUNER-AND VIF-AGC At Pin 8, the VIF-AGC charges/discharges the AGC capacitor to generate a control voltage for setting the gain of the VIF amplifier and tuner in order to keep the video output signal at a constant level. Therefore, in the case of all negative modulated signals (e.g., B/G standard) the sync. level of the demodulated video signal is the criterion for a fast charge/discharge of the AGC capacitor. For positive modulation (e.g., L standard) the peak white level of video signal controls the charge current. In order to reduce reaction time for positive modulation, where a large time constant is needed, an additional black level detector controls the discharge current in the event of decreasing VIF input signal. The control voltage (AGC voltage at Pin 8) is transferred to an internal control signal, and is fed to the tuner AGC to generate the tuner AGC current at Pin 11 (open collector output). The take over point of the tuner AGC is adjusted at Pin 10 by an external dc voltage from microprocessor. A PWM output from microcontroller is low pass filtered for this AGC control. See also AGC adjustment for details on how to align TOP in SERVICE mode. 5.2.4 FPLL, VCO AND AFC The FPLL circuit (frequency phase locked loop) consists of a frequency and phase detector to generate the control voltage for the VCO tuning. In the locked mode, the VCO is controlled by the phase detector and in unlocked mode, the frequency detector is superimposed. The VCO operates with an external resonance circuit (L and C parallel) and is controlled by internal varicaps. The VCO control voltage is also converted to a current and represents the AFC output signal at Pin 22. At the AFC switch (Pin 19) three operating conditions of the AFC are possible: AFC curve rising or falling and AFC off . A practicable VCO alignment of the external coil is the adjustment to zero AFC output current at Pin 22. At center frequency the AFC output current is equal to zero. Furthermore, at Pin 14, the VCO center frequency can be switched for setting to the required L value (L standard). The optional potentiometer at Pin 26 allows an offset compensation of the VCO phase for improved sound quality (fine adjustment). Without a potentiometer (open circuit at Pin 26), this offset compensation is not active. The oscillator signal passes a phase shifter and supplies the in-phase signal (? ) and the quadrature signal (9? )of the generated picture carrier.
-46-
CP830F Service Manual
5.2.5 VIDEO DEMODULATION AND AMPLIFIER The video IF signal, which is applied from the gain controlled IF amplifier, is multiplied with the inphase component of the VCO signal. The video demodulator is designed for low distortion and large bandwidth. The demodulator output signal passes an integrated low pass filter for attenuation of the residual vision carrier and is fed to the video amplifier. The video amplifier is realised by an operational amplifier with internal feedback and 8 MHz bandwidth (?3 dB). A standard dependent dc level shift in this stage delivers the same sync. level for positive and negative modulation. An additional noise clipping is provided. The video signal is fed to VIF-AGC and to the video output buffer. This amplifier with a 6 dB gain offers easy adaptation of the sound trap. For nominal video IF modulation the video output signal at Pin 12 is 2 Vpp. 5.2.6 SOUND IF AMPLIFIER AND SIF-AGC The SIF amplifier is nearly identical with the 3-stage VIF amplifier. Only the first amplifier stage exists twice and is switchable by a control voltage at Pin 3. Therefore with a minimal external expense it is possible to switch between two different SAW filters. Both SIF inputs features excellent cross-talk attenuation and an input impedance which is independent from the switching condition. The SIF-AGC is related to the average level of AM- or FM-carrier and controls the SIF amplifier to provide a constant SIF signal to the AM demodulator and QPS mixer. 5.2.7 QUASI-PARALLEL-SOUND (QPS) MIXER The QPS mixer is realised by a multiplier. The SIF signal (FM or NICAM carrier) is converted to the intercarrier frequency by the regenerated picture carrier (quadrature signal) which is provided from the VCO. The intercarrier signal is fed via an output amplifier to Pin 24. 5.2.8 STANDARD SWITCH To have equal polarity of the video output signal the polarity can be switched in the demodulation stage in accordance with the TV standard. Additional a standard dependent dc level shift in the video amplifier delivers the same sync. level. In parallel to this, the correct VIF-AGC is selected for positive or negative modulated VIF signals. In the case of negative modulation (e.g., B/G standard) the AM output signal is switched off. For positive modulation (L standard) the AM demodulator and QPS mixer is active. This condition allows a parallel operation of the AM sound signal and the NICAM-L stereo sound. 5.2.9 L SWITCH With a control voltage at Pin 14 the VCO frequency can be switched for setting to the required L value (L standard). Also a fine adjustment of the L -VCO center frequency is possible via a potentiometer. The L switch is only active for positive modulated video IF-signals (standard switch in L mode). 5.2.10 INTERNAL VOLTAGE STABILISER The internal bandgap reference ensures constant performance independent of supply voltage and temperature. 5.3 VIDEO / RGB 5.3.1 FRONT END 5.3.1.1 CVBS Front-End The CVBS front-end consists of the colour-decoding circuit itself, a sync processing circuit for generation of H/V signals out of the CVBS signal, and the luminance processing. The main task o