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17. Disconnect the cables connected to IFa in and IFa out of the unit.
18. Adjust the spectrum analyzer so that the compression modulation
peak level can be seen clearly on the spectrum analyzer screen.
(Use this item as the reference level.)
19. Set the variable resistance attenuator to 0 dB.
20. Adjust control VR1 (RV1) of the RF ASSY so that the bottom
level in the compression modulation of the signal comes to the
position set in step 7.
[Adjustment waveform diagram 1] : [Example of Key Modulation Rate (5.5 dB)]
*2 The above shows one example of the adjustment waveform. Be
sure to adjust using the attenuator substitution method. Do not
perform adjustment on the screen.
4.9 Setting the Switches of the
LOGIC Assy
Set switches as shown above.
REF 100.9 dBµV
ATT 10 dB
1dB/
VERTICAL
1dB/
RBW
1 MHz
VBW
1 MHz
SWP
200 ms
CENTER 41.250 MHz
Fig. 4-11 Adjustment Waveform Diagram 1
Switch No.
S1
S2
S3
S4
S5
Jumper No.
P1
P3
21. Repeat the adjustments in section 4.6 and the adjustments in steps
1 to 20 in section 4.8 three times to raise the accuracy.
*1 Observe the following values when adjusting the modulation
distortion and compression distortion to facilitate the adjustments.
• Clear mode: Meter reading
• 6/10 dB mode: Noise waveform on oscilloscope
A_write B_blank
1dB/div
VBW:1MHz
RBW:1MHz
SPAN:1MHz
ST:200ms
SPAN 1.000 MHz
ALL OFF
ALL OFF
0
NA
D
DE side
Not TEST side
BE-3110
27
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