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Page 16.03
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
(5) A8VR501 adjusts the blanking level, and A8VR502 adjusts the total
amplitude of the composite video signal as shown in Figure 8.
A8VR501 ADJUSTS
THIS LEVEL.
A8VR502 ADJUSTS
THIS AMPLITUDE.
WHITE RASTER OUTPUT OF A8 CARD
Figure 8
(6) A8Q502 and A8Q503 operate as an amplifier with a low output
impedance.
(7) A8IC504 (voltage regulator) gives regulated DC power of +5 V to the
circuits on the A8 card. The TG CONT signal from the A1 card on-off
controls A8IC504. Thus, the A8 card circuits operate only when the
TG CONT signal is low.
(8) A8RL501 (electromagnetic relay) is energized when the A8 card DC
power becomes on, and selects the white raster output from A8Q503
for modulator channel 2. When A8RL501 is de-energized with the TG
CONT signal high, it selects the video channel 2 input for modulator
channel 2.
(9) No connection is usually made to the A8CN503 connector. The factory
uses this connector for adjustment of A8VR501 and A8VR502.
Page 16.04
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
K. Video Signal Generator Card Assembly (A8), Second Type
(1) A8X501 Crystal Oscillator
A8X501 gives a 14.318-MHz clock from its pin 3 with its pin 1 (OE or
output enable) pulled up to +5 V.
(2) A8IC501 Video Signal Generator
A8IC501 is a programmable logic device that is programmed as a video
signal generator.
A8IC501 receives 14.318-MHz clock (four times the NTSC color
subcarrier frequency) from A8X501 and gives:
· NTSC composite sync output from its pin 29
· NTSC luminance output (white raster) from its pin 39.
The amplitude of these outputs is approximately 4 Vp-p. Refer to
Figure 9 for their waveforms.
(3) Test Video Signal
A8IC502 contains two operational amplifiers, A8IC502A and A8IC502B.
These amplifiers put A8IC501 pin 29 and 39 outputs together to make
the test video signal. Refer to Figure 9 for the block diagram of
the circuit.
A8IC502A receives A8IC501's pin 39 output and gives an inverted
output.
A8IC502B receives A8IC501's pin 29 output and A8IC502A output, which
are put together at A8IC502B input. A8IC502B also makes inversion
of the signal.
A8IC502B output is as shown in Figure 9. The amplitude "B"
(composite sync) is approximately 0.6 Vp-p. There is no adjustment
for this amplitude.
The amplitude "A" (video, luminance only) is approximately 1.0 Vp-p
for the 72% white raster. This is given as:
0.7 (100% white) x 0.72 x 2 = 1.0
A8VR501 adjusts the amplitude "A".
A8R502 (51-W resistor) is connected in series with A8IC502B output
as the output impedance.
Page 16.05
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
A (VIDEO)
B (SYNC)
REF
REF
A8IC501
PIN 39
OUTPUT
(WHITE 72%)
PIN 29
OUTPUT
(COMPOSITE
SYNC)
A8IC502A
A8IC502B
A8VR501
A8R502
51 W
A8IC501
PIN 39
OUTPUT
A8IC501
PIN 29
OUTPUT TO A8RL501
A4IC303B
OUTPUT
A4VR301 ADJUSTS AMPLITUDE "A".
APPROX.
4 V
APPROX.
4 V
(TEST VIDEO)
A8IC501 OUTPUTS AND TEST VIDEO SIGNAL
Figure 9
Page 16.06
Feb 20/2002
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
(4) A8IC504 (voltage regulator) gives regulated DC power of +5 V to the
circuits on the A8 card. The TG CONT signal from the A1 card on-off
controls A8IC504. Thus, the A8 card circuits operate only when the
TG CONT signal is low.
(5) A8RL501 (electromagnetic relay) is energized when the A8 card DC
power becomes on, and selects the white raster output from A8IC502B
for modulator channel 2. When A8RL501 is de-energized with the TG
CONT signal high, it selects the video channel 2 input for modulator
channel 2.
(6) No connection is usually made to the A8CN503 connector. The factory
uses this connector for adjustment of A8VR501.
Page 17
Dec 20/2000
Matsushita Avionics Systems Corporation
COMPONENT MAINTENANCE MANUAL
PART NUMBER RD-AA5002 SERIES
23-32-47
5. VMU-VSCU Communications
NOTE: The term "VSCU" includes both the VSCU used in System 2000 design and
the EVSCU used in System 2000E design.
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COMPONENT MAINTENANCE MANUAL Video Modulator Unit (VMU)(23)
