3-56 Chapter 3
Adjustments and Correction Constants
Sequences for Mechanical Adjustments
How to Set Up the High/Low Band Transition Adjustments
1. Press (where X is the sequence number).
2. Observe the VCO tuning trace:
• If the left half of trace = 0 ± 1000 mV and right half of trace = 100 to 200 mV higher
(one to two divisions): no adjustment is necessary.
• If the adjustment is necessary, follow these steps:
a. Remove the upper-rear bumpers and top cover, using a TORX screwdriver.
b. Adjust the VCO tune (A12 C85) to position the left half of the trace to 0 ± 125 mV.
This is a very sensitive adjustment where the trace could easily go off of the
screen.
c. Adjust the HBLB (A12 R68) to position the right half of the trace 125 to 175 mV
(about 1 to 1.5 divisions) higher than the left half.
• Refer to Chapter 7 , “Source Troubleshooting,” if you cannot perform the adjustment.
How to Set Up the Fractional-N Spur Avoidance and FM Sideband
Adjustment
1. Press (where X is the sequence number).
2. Remove the upper-rear corner bumpers and the top cover, using a TORX screwdriver.
3. Follow the directions on the analyzer display and make all of the API adjustments.
Sequence Contents
Sequence for the High/Low Band Transition Adjustment
— Sequence HBLBADJ sets the hi-band to low-band switch point. —
PRESET
SYSTEM
SERVICE MENU
ANALOG BUS ON
START 11 M/u
STOP 21 M/u
MEAS
ANALOG IN 22 x1 (A12 GND)
DISPLAY
DATA > MEM
DATA − MEM
MEAS
ANALOG IN 23 x1 (VCO TUNE)
MKR 11 M/u
SCALE/REF .1 x1
Preset
Preset
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