Panasonic EURO 4 Chassis Technical Manual page 161

3DQDVRQLF
Chapter 4
9.3. Video Signal Source
9.3.1. Video Switching Inputs
Signals input to the video switching IC IC 3401, are
applied from a number of sources. These are shown
below:
:
Pin 1 - Mon Vin
The input at pin 1 is the monitor input, when this input
is selected what is being viewed on screen is output
via AV2.
:
Pin 3 - DVB Vin
Pin 3 allows the input of a video signal fed from the
DVB decoder located on the V-Board
:
Pin 5 - DVB Yin
The luminance component of a S-VHS signal fed from
the DVB decoder is input via pin 5.
:
Pin 6 DVB Cin
This input allows the chrominance component of an
S-VHS signal to be input fed from the DVB decoder.
:
Pin 10 - AV3 Cin
Pin 10 is fed the chrominance component of an
S-VHS signal source input via the 4 pin S-VHS AV3
terminal, located on the M-Board.
:
Pin 11 - TV In
The video information fed from the tuner located on
the E-Board is input via pin 11, from here the video
signal is fed to the VDP IC601 for further processing
as well as being fed to either AV1 or AV2 terminals.
:
Pin 20 - AV2 Cin
The AV2 terminal allows the input of a chrominance
signal via pin 15, fed from an S-VHS source which is
input via pin 20 of IC3401.
9.3.2. Video Switching Outputs
:
Pin 13 - Main Cout
The output via pin 13 is the chrominance signal fed
from any of the chrominance inputs mentioned above.
The chrominance signal output from pin 13 of IC3401
is fed to the base of buffer transistor Q3441, which is
also used to detect the chrominance signal being
output from pin 13. This detection being used to
ensure that no interference occurs in any of the
subsequent processing paths.
To detect a chrominance signal output via pin 15 a d.c.
bias level is applied to the chrominance signals input
to the switching IC IC3401, this is achieved via 100K
resistors located at the inputs.
This d.c. bias is then used to switch transistor Q3441
ON allowing the chrominance signal to be buffered
and output via Q3441 where the signal is split into two
paths.
The first path feeds the chrominance signal via
transistor Q3442 where the signal is fed to pin 60 of
the VDP IC601 located on the E-Board for further
processing.
The second path that the chrominance signal follows
from the output of transistor Q3441 is to transistor
Q3443. Here the chrominance signal is mixed with the
luminance signal fed from pin 59 of the VDP IC601.
This mixed chrominance and luminance video signal
is once again buffered by transistor Q3444 before
being fed to back to the switching IC IC3401 and the
monitor input pin 1 mentioned in the previous section..
Where there is no chrominance signal output from pin
13 of the switching IC IC3401 then the buffered
transistor Q3441 is switched OFF. However a video
signal output from the pin 59 is then fed to via
transistors Q3443, Q3444 and again fed to the
monitor input pin 1 of IC3401.
:
Pin 14 - Main Y / V out
Pin 14 of the switching IC IC3401 outputs either the
luminance component of an S-VHS source or a
composite video signal which is then fed to the VDP
pin 61 for further processing and viewing on screen.
:
Pin 15 - AV1 Vout
Pin 15 allows the output of a video signal which is then
fed to pin 19 of the AV1 21 pin scart terminal.
:
Pin 16 - AV2 Vout
Output from pin 16 of the switching IC IC3401 is a
video signal which is fed to the AV2 21 pin scart
terminal.
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EURO 4D Supplement
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