3-36
CCU-700A
CCU-700AP
3.
Change the output signal of the video signal generator
to 10 STEP signal.
4.
Re-adjust
1
LV3 (PROMPT TUNE)/DM-94 board so
that the “A” portion at video waveform is flat.
(
Note
:If not met, Re-perform “3-7-3. RX PROMPT
VIDEO Demod. Adjustment” after performing “3-7-4.
RX PROMPT VIDEO RF AGC Adjustment”.)
Note
: After the adjustment, set the switches as follows.
• S4 (CCU
→
CAM/CAM
→
CCU) switch/
MD-83 board (BVP side)
→
“CCU
→
CAM”
• Return the green harness of MPX filter to CN35
(PROMPT) connector on DM-97 board (BVP side).
• S5 (TX
←
→
RX) switch/DM-94 board
→
“TX”
• S6 (TX
←
→
RX) switch/DM-94 board
→
“TX”
• Remove the BNC cable from the PROMPTER
connector/CCU rear panel.
A
Flat
6MHz
3-7-3.
RX PROMPT VIDEO Demod. Adjustment
Rank
:
C
Note
:
Perform the adjustment only when
replacing
1
LV2 (PROMPT RX
FREQ) or
1
LV3 (PROMPT RX
TUNE)/DM-94 board.
When adjusting this step, the length
of triaxial cable is required less than
500 m.
Adjustment of BVP-700/700P must
be completed.
Equipment
:
Oscilloscope, Video signal generator
(SWEEP, 10 STEP signal)
To be extended
:
DM-94 board
Preparation
• S4 (CCU
→
CAM/CAM
→
CCU)/
MD-83 board (BVP side)
→
“CAM
→
CCU”
• Remove the green harness of MPX filter from CN35
(PROMPT) connector on DM-97 board (BVP side).
And connect its harness to CN27 (PROMPT
REVERSE)/MB-430 board (BVP side).
• S5 (TX
←
→
RX)/
DM-94 board (CCU-700A/700AP)
→
“RX”
• S6 (TX
←
→
RX)/
DM-94 board (CCU-700A/700AP)
→
“RX”
• S1 (MODE AUTO/MAN)/
DM-94 board (CCU-700A/700AP)
→
“AUTO”
• Feed the SWEEP signal from the video signal generator
to PROMPTER connector (CCU rear panel).
Test point
:
pin D34 (GND: pin C34)/
extension board
Adjusting point
:
1
LV2 (PROMPT FREQ)/
DM-94 board
1
LV3 (PROMPT RX TUNE)/
DM-94 board
Adjustment Procedure
1.
Observe the waveform monitor screen and adjust
1
LV3 (PROMPT RX TUNE)/DM-94 board so that
the video waveform is appeared.
2.
Adjust
1
LV2 (PROMPT FREQ)/DM-94 board so that
the frequency response at 6 MHz portion is minimum.
3-7. PROMPT VIDEO Cable Compensation System Adjustment