Microcontroller And Small Signal Processor Data; Service Data; Technical Data Of Key Ics - Changhong Electric 21NF55 Service Manual

SERVICE DATA

1. KEY ICS TECHNICAL DATA
1.1 Microcontroller and small signal processor TDA935X/6X/8X
The super chips TDA935X/6X/8X are good in pins compatibility. Differences among them are shown
as follows.
TDA9351（48K）
TDA9350（48K）
TDA9361（64K）
TDA9360（64K）
TDA9380（32K）
TDA9387（32K）
TDA935X/6X/8X PS/N2 series TV signal processor-Teletext decoder with embedded
？ -Controller
1) General Description
The various versions of theTDA935X/6X/8X PS/N2 series combine the functions of a TV signal
processor together with a ？ -Controller and US Closed Caption decoder. Most versions have a
Teletext decoder on board. The Teletext decoder has an internal RAM memory for 1or 10 page text.
The ICs are intended to be used in economy television receivers with 90 ? a nd 110
The ICs have supply voltages of 8 V and 3.3 V and they are mounted in S-DIP envelope with 64
pins.
The features are given in the following feature list. The differences between the various ICs are
given in the table on page 4.
2) Features
TV-signal processor
● Multi-standard vision IF circuit with alignment-free PLL demodulator
● Internal (switchable) time-constant for the IF-AGC circuit
● A choice can be made between versions with mono intercarrier sound FM demodulator and
versions with QSS IF amplifier.
● The mono intercarrier sound versions have a selective FM-PLL demodulator which can be switched
to the different FM sound frequencies (4.5/5.5/6.0/6 .5 MHz).
The quality of this system is such that the external band -pass filters can be omitted.
● Source selection between ' internal' CVBS and external CVBS or Y/C signals
● Integrated chrominance trap circuit
● Integrated luminance delay line with adjustable delay time
● Picture improvement features with peaking (with variable centre frequency and positive/negative
overshoot ratio) and black stretching
● Integrated chroma band-pass filter with switchable centre frequency
● Only one reference (12 MHz) crystal required for the
● -Controller, Teletext- and the colour decoder
● PAL/NTSC or multi -standard colour decoder with automatic search system
SERVICE MANUAL
PAL/NTSC/SECAM+1 PAGE TELETEST
PAL/NTSC+1 PAGE TELETEST
PAL/NTSC/SECAM+10 PAGE TELETEST
PAL/NTSC+10 PAGE TELETEST
PAL/NTSC
NTSC
17
？ ？
? p icture tubes.