EN 649.L01.1E ABCircuit Description
9. Circuit Description
Index of this chapter:
1. IntroductionThe L01 is divided into 2 basic systems, i.e. mono and stereo
2. Audio Signal Processingsound. While the audio processing for the mono sound is done
3. Video Signal Processingin the audio block of the UOC, an external audio processing IC
4. Synchronisationis used for stereo sets.
5. Deflection
6. Power SupplyThe tuning system features 100 video channels with on-screen
7. Controldisplay. The main tuning system uses a tuner, a
8. Abbreviationsmicrocomputer, and a memory IC mounted on the main panel.
Also, in some type numbers, an FM radio is implemented with
Notes: 40 pre-set channels.
Figures can deviate slightly from the actual situation, due The microcomputer communicates with the memory IC, the
to different set executions.customer keyboard, remote receiver, tuner, signal processor IC
2
For a good understanding of the following circuit and the audio output IC via the IC bus. The memory IC retains
descriptions, please use the block diagram in chapter 6, or the settings for favourite stations, customer-preferred settings,
the electrical diagrams in chapter 7. Where necessary, you and service/factory data.
will find a separate drawing for clarification.The on-screen graphics and closed caption decoding are done
within the microprocessor, and then sent to the signal
processor IC to be added to the main signal.
9.1Introduction
The chassis uses a Switching Mode Power Supply (SMPS) for
The L01 chassis is a global TV chassis for the model year 2001 the main voltage source. The chassis has a ?hot? ground
and is used for TV sets with screen sizes from 14? - 21? (small reference on the primary side and a cold ground reference on
screen) to 21? - 32? (large screen). the secondary side of the power supply and the rest of the
The standard architecture consists of a Main panel, a Picture chassis.
Tube panel, a Side I/O panel (not al executions) and a Top
Control panel.
9.2Audio Signal Processing
The Main panel consists primarily of conventional components
with hardly any surface mounted devices.
9.2.1 Stereo
In stereo sets, the signal goes via the SAW filter (position 1004
in case of QSS demodulation and 1003 in case of Intercarrier
demodulation), to the audio demodulator part of the UOC
IC7200. The stereo audio output on pin 33 goes, via TS7206,
to the stereo decoder 7831.
2
The switch inside the stereo decoder 7831 selects (via IC)
either the internal decoder or an external source.
The NICAM + 2CS AM/FM stereo decoder is an ITT MSP34X5.
The output is fed to the to the audio amplifier (AN7522 at
position 7901). The volume level is controlled at this IC (pin 9)
by a control line (VolumeMute) from the microprocessor. The
audio signal from 7901 is then sent to the speaker/headphone
output panel.
Figure 9-1 AUDIO SOURCE SELECTION
EXT. AUDIO78017861
INPUT7831
EXT. AUDIO OUT
CONTROL
The functions for video processing, microprocessor (?P) and 7209ANDAUDIO DECODING
7210PROCESSING7901
SELECTIONMATR. SWITCH
teletext (TXT) decoder are combined in one IC (TDA958xH), FM BFM IFUFFERFMR472425AUAMPL.DIO
the so-called Ultimate One Chip (UOC). This chip is (surface) 78347200337835
mounted on the copper side of the main panel.RF ANT.23SIFSOUND
FM ANT.SAWFILTER24
DEMODIF .
1000
0265107602
11TUNER11SAW18VIFVISIONIF?P68NVM
1FILTER19DEMOD.
AGC22 I2C
1200 : 120250:53EXT RGB/YUV INPUT
SOUND38TRAP
7330
INT_CVBS40VIDEORGB/YUV56:58VIDEO
PROCESSINGPROCESSING
EXT. VIDEOEXT_CVBS42AMPL.INPUT7802
VIDEOPROCESSINGEHTSYNC
SWITCH
VIDEO SOURCE16 17 15 307460
SELECTIONH
HOR.
DEFL.
VBATEW+EW
AUDIO
POWERSUPPLY12VV+7471
3.9V
3.3VV-VERDEFL.T.
CL 16532008_039.eps
220501
Figure 9-3
Figure 9-2 |
ACEC
