
7. 3 MHz Bandwidth Filter Adjustments
Filter
Peak
Adjust
Note
The adjustment ranges of
A4A7C13
PK,
A4A7C22
PK,
A4A7C31
PK, and
A4A7C40
PK are all indirectly affected by factory-select
components
A4A7C93
and
A4A7C5.
A4A7C93
and
A4A7C5
set the
peak frequency for the first 3 MHz filter pole, setting the reference for
peaking the amplitudes of the remaining 4 poles. In the following
steps, decrease or increase the value of
A4A7C93
and
A4A7C5
as
necessary only if adjustments
A4A7C13
PK,
A4A7C22
PK,
A4A7C31
PK, and
A4A7C40
PK are all near the same end of their adjustment
range (fully meshed, maximum capacitance, or unmeshed, minimum
capacitance). If the adjustable capacitors are fully meshed, decrease
the value of
A4A7C93.
18.
Press @?ZZiQ
19. Key in [SWEEP TIME] 20 ms, [FREQUENCY SPAN) 0 Hz,
@iZZZ@
10 Hz,
(REFERENCE LEVEL] -20
dBm.
20. Set the frequency synthesizer for 21.400 MHz at an amplitude
level of -25.0
dBm.
21. Disconnect cable 97 (white/violet) from A4A8Jl and connect
22
Set the oscilloscope following Settings:
output of the frequency synthesizer to
A4A8Jl
using BNC to SMB
snap-on cable.
Press
ICHANl
Channel 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .on
probe
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1O:l
amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 mV/div
coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
..ac
Channel 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . on
probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1O:l
amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 mV/div
coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
..ac
Press
m
EDGE TRIGGER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . auto, edge
source
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
..Channell
Press (TIME)
time scale
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
200 ns/div
Press (DISPLAY)
connect dots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
..on
Press
(SHOWI)
23. Connect the oscilloscope channel 1 probe to
A4A7TP7
(left side of
Cl4 SYM) and the channel 4 probe to
A4A7TP5
(left side of C23
SYM).
24. Adjust the frequency synthesizer output frequency for maximum
peak-to-peak signal on the oscilloscope channel 1 display.
25. Adjust
A4A7C13
PK for maximum peak-to-peak signal on channel
4 display. See Figure 3-39 for location of adjustment. If unable to
achieve 1 “peak” in signal amplitude, increase or decrease value
of
A4A7C12.
Refer to
‘Ihble
3-3 for range of values.
Adjustments 3-79
Kommentare zu diesen Handbüchern