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3)Pin Function
Audio deemphasis
iF-demodulator tuned circuit
IF-demodulator tuned circuit
Video indentification output
Sound IF in plus volume control
External audio input
IF video output
Decoupling digital supply
Ground
Positive supply (8 V)
Ground
Decoupling filter tuning
Internal CVBS input
Peaking control input
External CVBS input
Chroma + A/V switch input
Brightness control input
B-output
G-output
R-output
RGB-insertion and blanking input
R-input for insertion
G-input for insertion
B-input for insertion
Contrast control input
Saturation contro! input
OONOAO
AWD
2.CHROMA VIDEO SECTION
1)Block-Diagram
4.43MHz
&
ni
TDA8&362
27
SHRY) 3148-Y)
BEY)
BRY)
Reference
chroma
L: PAL
'H:SECAM
1
16
g
SECAM
Oecorder
ToAss95
—-10
2)Actuating Description
- Colour Decoder
The
colour decoder contains an alignment-free X-tal
oscillator, a dual killer circuit and the colour difference
signals demodulators. The decoder adapts automatically
for PAL and NTSC signals. Two X-tal pins are present so
no external switching is required. With the SECAM add-
on decoder TDA8395 an alignment free multi-standard
26
[ee [Fanon
Decoupling bandgap supply
Decoupling sound demodulator
Audio output
Tuner take-over adjustment
AGC decoupling capacitor
Tuner AGC output
IF-input
IF-AFC output
AFC output
Vertical output
Vertical ramp generator
Vertical feedback input
@ -1 loop filter
@ 1- loop filter
Flyback input / sandcastle output
Horizontal output
Start horizontal oscillator
4.43MHz X-tal connection
3.58MHz X-tal connection
Loop filter burst phase detector
4.43MHz output for TDA 8395
B-Y output signal
R-Y output signal
R-Y input signal
B-Y input signal
Hue control input (or chroma out)
decoder can be built with an automatic selection. This
makes the application of the TDA8362 very flexible. The
following applications are possible:
~ PALISECAM:
In this application pin 27 is not used for Hue-control but
for the chroma signal for the SECAM
add-on circuit. Pin
27 has to be connected to the supply line 8V via a series
resistor of 10k2. Together with the alignment-free SECAM
add-on
circuit TDA8395
a PAL/SECAM
decoder is
realized.
The burst phase detector locks the X-tal oscillator with the
burst signal. Two gain modes
provide an increased
catching range when the PLL is unlocked and a low ripple
voltage and a good noise immunity when the PLL is
locked.
The burst phase detector operates. during the burst key
period only, to prevent the PLL from being disturbed by
the chroma signal.
The
killer circuit switches
off the R-Y
and
B-Y
demodulators
at too low input signal condition (burst
amplitude). Proper hysteresis prevent the constant on/off
switching at a certain input level.
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