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 LO-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
PinSymbolFunction
1, 2Vi, SIF1SIF1 input (symmetrical)
3VSWInput selector switch
4, 9, 16GNDGround
5VAGCSIF - AGC (time constant)
6, 7Vi, VIFVIF input (symmetrical)
8CAGCVIF - AGC (time constant)
10RTOPTake Over Point, tuner AGC
11ItunTuner AGC output current
12VO, VIDVideo output
13VSWStandard switch
14VSWL O switch
15CblBlack level capacitor
17CrefInternal reference voltage
18LFLoop Filter
19VSWAFC switch
20, 21VVCOVCO circuit
22VAFCAFC output
23VSSupply voltage
24VO, FMIntercarrier output
25VO, AMAF output - AM sound
26RcompOffset compensation
27, 28Vi, SIF2SIF2 input (symmetrical)
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ACEC
DAEWOO
