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The tuner A.G.C. (pin 47) is an open collector output
stage with an output swing of 2mA min. The voltage
swing,required by the tuner, can be obtained with an
external resistor network, connected at pin 47. Pin 47 may
rise 2V above the actual supply voltage, without damaging
the IC.
This feature simplifies the application, because most
3)IC Block-Diagram (TDA8362)
Ref-circuit
if amplifier
OverLoad
AGCkey
4.SOUND SECTION
1)Block-Diagram
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Z101
SAW FILTER
2201,2202,
2203
SOUND TRAP
Se
Video Identificalion
tuners require a 9V A.G.C. voltage level for min. gain.
The A.F.C. circuit is driven by the same reference signal
as the video demodulator.A sample and hold circuit
avoids video break-through from the video demodulator to
the A.F.C. voltage. The A.F.C. output voltage range is
from 0 to Vcc, the stepness of the A.F.C. slope can be
influenced by resistors R114 and R115.
Video buffer
S&H gate
AFC
output
ident
Colour info
coincidence
VIDEX
2)Actuating Description
The sound bandpass and trap filters have to connected
externally. For automatic system converting,the filtered
inter carrier signal is fed to TA8710S (sound converter IC).
The inputed sound signal is converted to 6.0MHz singnal.
The converted sound signal is fed to alimilter circuit and is
demodulated by means of a PLL demodulator. This PLL
circuit itself tunes
automatically to the incoming signal so
that no adjustment is required, In case of NTSC, Sound
signal is filtered to 4.5MHz BPF. The filtered intercarrier
_signal is fed to pin 5 of TDA8362.
The volume is the DC-controlled. The composite audio
output
signal has the amplitude of 700mV RMS
at
maximum
volume
control setting. The deemphasis
capacitor has to be connected
externally. The non-
controlled audio signal can be obtained from this pin (via a
buffer stage). The amplitude of this signal is 350mV RMS.
The external audio input signai must have an amplitude of
350MV RMS. The audio/video switch is contolled via the
chroma input pin(pin16).
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