SANYO CEP2558T-00 CHASSIS E3 UNITS VIEW.

- Power supply + Audio Ampl Board : EB2888A

- Teletext Unit : EB2621AXA

- S-TERM UNIT : EB2923A

- VIDEO CHROMA UNIT : EB2923B

- STEREO UNIT : EB2922A


CIRCUITS DESCRIPTION:

TDA4555 Multistandard decoder.


GENERAL DESCRIPTION
The TDA4555 and TDA4556 are monolithic integrated
multistandard colour decoders for the PAL, SECAM,
NTSC 3,58 MHz and NTSC 4,43 MHz standards. The
difference between the TDA4555 and TDA4556 is the
polarity of the colour difference output signals (B-Y)
and (R-Y).
Features
Chrominance part
· Gain controlled chrominance amplifier for PAL, SECAM
and NTSC
· ACC rectifier circuits (PAL/NTSC, SECAM)
· Burst blanking (PAL) in front of 64 ms glass delay line
· Chrominance output stage for driving the 64 ms glass
delay line (PAL, SECAM)
· Limiter stages for direct and delayed SECAM signal
· SECAM permutator
Demodulator part
· Flyback blanking incorporated in the two synchronous
demodulators (PAL, NTSC)
· PAL switch
· Internal PAL matrix
· Two quadrature demodulators with external reference
tuned circuits (SECAM)
· Internal filtering of residual carrier
· De-emphasis (SECAM)
· Insertion of reference voltages as achromatic value
(SECAM) in the (B-Y) and (R-Y) colour difference output
stages (blanking)
Identification part
· Automatic standard recognition by sequential inquiry
· Delay for colour-on and scanning-on
· Reliable SECAM identification by PAL priority circuit
· Forced switch-on of a standard
· Four switching voltages for chrominance filters, traps
and crystals
· Two identification circuits for PAL/SECAM (H/2) and
NTSC
· PAL/SECAM flip-flop
· SECAM identification mode switch (horizontal, vertical
or combined horizontal and vertical)
· Crystal oscillator with divider stages and PLL circuitry
(PAL, NTSC) for double colour subcarrier frequency
· HUE control (NTSC)
· Service switch.



TV Stereo Decoder with Matrix TDA 6600 2
SIEMENS
Preliminary Data Bipolar IC
The TDA 6600-2 includes an advanced decoder for the identification signals for the
multichannel TV sound systems according to the dual-carrier system as well as a matrix
switched by the decoder to provide the L-Ft-information.
Features
0 Increased switching reliability and recognition by means of two PLLs for stereo
(117 Hz) and / or dual channel (274 Hz)
0 Separate bandwidth selection for dual-tone (pins 17-18) and stereo (pins 14-15)
0 Separate setting for the PLL time constants for dual-tone (pin 10) and stereo (pin 11)
0 Adjustable cut level for dual-tone (pin 8) and stereo (pin 9)
0 Cross-talk rejection independent of external component accuracy
0 Adjustment to minimal cross-talk level through external DC voltage
0 Suitable for TV sets with a 15625-Hz signal.
Type Ordering Code Package
TDA 6600-2 Q67000-A8210 P-DlP-24
Circuit Description
The circuitry has two functional sections:
Two phase locked loops for generating the required comparison frequencies (54.96
kHz and 54.8 kHz) from the line frequency. The phase detectors of the control loops
operate in a frequency range of 117 Hz and/or 274 Hz.
Four demodulators to evaluate the 54-kHz pilot signal. The capacitors at the mixer
outputs determine the bandwidth (and thus the signal-to-noise ratio) of the pilot tone
recognition.
An evaluation circuitry for decoding "stereo", "dual sound", and "mono" from the mixer
output levels. ln order to assure interference-free operation in case of high noise level
input signals, the individual signals "stereo" and "dual sound" are delayed via an
externally adjustable integrator. The subsequent digital evaluation provides the
information "mono", "dual sound", or "stereo" to the matrix and the 4 level input/output
(to drive the TDA 6200). If this four level input/output is connected to ground externally
(e.g. by the TDA 6200), the decoder will recognize this signal as "forced mono".
A stereo matrix with deemphasis and SCART output switched by the pilot frequency
decoder. The SCART output can be disabled by a MUTE signal (coincidence).




TDA4565

Colour transient improvement
circuit

GENERAL DESCRIPTION
The TDA4565 is a monolithic integrated circuit for colour transient improvement (CTI) and luminance delay line in gyrator
technique in colour television receivers.
Features
· Colour transient improvement for colour difference signals (R-Y) and (B-Y) with transient detecting-, storage- and
switching stages resulting in high transients of colour difference output signals
· A luminance signal path (Y) which substitutes the conventional Y-delay coil with an integrated Y-delay line
· Switchable delay time from 730 ns to 1000 ns in steps of 90 ns and additional fine adjustment of 50 ns
· Two Y output signals; one of 180 ns less delay.



TDA2556 QUASI-SPLIT-SOUND CIRCUIT WITH DUAL SOUND DEMODULATORS

GENERAL DESCRIPTION
The TDA2556 is a monolithic integrated circuit for quasi-split-sound processing, including two FM
demodulators, for two carrier stereo TV receivers and VTR.
Features
First IF (vision carrier plus sound carrier).
0 3 stage gain controlled IF amplifier
0 AGC circuit
0 Reference amplifier and limiter amplifier for vision carrier (V.C.) processing
0 Linear multiplier for quadrature demodulation
Second IF (two separate channels for both FM sound signals).
0 4-stage-limiting amplifier
0 Ouadrature demodulator
0 AF amplifier with de-emphasis
O Output buffer
0 Muting for one or both AF outputs


SIEMENS TDA 6200TV Stereo Tone Control IC with Quasi-Stereo Section,
Channel 1/2 Switch, SCART Input, and I2C Bus Control

Features
0 Treble, bass, balance, and volume control by means of an integrated digital-to-analog
converter
I Quasi~stereo circuit during mono operation
0 Stereo basewidth expansion during stereo operation
O Physiological volume control
I Channel 1/2 switch-over during dual audio transmission
0 SCART connection
0 Control of all functions via the IZC bus and the bidirectional 4 level line of the
TDA 6600-2 (stereo demodulator IC)
O LED driver
0 Volume control range 80 dB
0 Treble, bass control 1 ‘I2 dB
O Channel separation min. 60 dB, cross-talk rejection min. 60 dB
O Parasitic voltage spacing up to 78 dB
Type W W Ordering Code Package
TDA 6200 Q67000-A2461 P-DIP-28
The TDA 6200 is comprised of a SCART switch-over, channel 1/2 switch-over, quasi-
stereo circuit, stereo basewidth expansion, physiological volume control, a treble, bass,
and volume control of the injected AF signals as well as an LED driver. The IC is
controlled by means of an FC bus serial interface as well as by the bidirectional 4 level
line from the TDA 6600-2. The component is used for AF sound signal processing in
stereo TV sets.



TDA3505 Video control combination circuit with automatic cut-off control.

GENERAL DESCRIPTION
The TDA3505 and TDA3506 are monolithic integrated circuits which perform video control functions in a PAL/SECAM
decoder. The TDA3505 is for negative colour difference signals -(R-Y), -(B-Y) and the TDA3506 is for positive colour
difference signals +(R-Y), +(B-Y).
The required input signals are: luminance and colour difference (negative or positive) and a 3-level sandcastle pulse for
control purposes. Linear RGB signals can be inserted from an external source. RGB output signals are available for
driving the video output stages. The circuits provide automatic cut-off control of the picture tube.
Features
· Capacitive coupling of the colour difference and
luminance input signals with black level clamping in the
input stages
· Linear saturation control acting on the colour difference
signals
· (G-Y) and RGB matrix
· Linear transmission of inserted signals
· Equal black levels for inserted and matrixed signals
· 3 identical channels for the RGB signals
· Linear contrast and brightness controls, operating on
both the inserted and matrixed RGB signals
· Peak beam current limiting input
· Clamping, horizontal and vertical blanking of the three
input signals controlled by a 3-level sandcastle pulse
· 3 DC gain controls for the RGB output signals (white
point adjustment)
· Emitter-follower outputs for driving the RGB output
stages
· Input for automatic cut-off control with compensation for
leakage current of the picture tube.
Notes
1. < 110 mA after warm-up.
2. Values are proportional to the supply voltage.
3. When V11-24 < 0,4 V during clamping time - the black levels of the inserted RGB signals are clamped on the black
levels of the internal RGB signals.
When V11-24 > 0,9 V during clamping time - the black levels of the inserted RGB signals are clamped on an internal
DC voltage (correct clamping of the external RGB signals is possible only when they are synchronous with the
sandcastle pulse).
4. When pins 21, 22 and 23 are not connected, an internal bias voltage of 5,5 V is supplied.
5. Automatic cut-off control measurement occurs in the following lines after start of the vertical blanking pulse:
line 20: measurement of leakage current (R + G + B)
line 21: measurement of red cut-off current
line 22: measurement of green cut-off current
line 23: measurement of blue cut-off current
6. Black level of the measured channel is nominal; the other two channels are blanked to ultra-black.
7. All three channels blanked to ultra-black.
The cut-off control cycle occurs when the vertical blanking part of the sandcastle pulse contains more than 3 line
pulses.
The internal blanking continues until the end of the last measured line.
The vertical blanking pulse is not allowed to contain more than 34 line pulses, otherwise another control cycle begins.
8. The sandcastle pulse is compared with three internal thresholds (proportional to VP) and the given levels separate
the various pulses.
9. Blanked to ultra-black (-25%).
10. Pulse duration ³ 3,5 ms.