Technical data

8510C Service Quick Reference Guide 3-7
8510C Adjustments
Procedure 5. Trim Sweep
Procedure 5. Trim Sweep
Trim Sweep performs a different function for 8340/41 and 8350 sources. For 8340 sources
set for ramp sweep mode, it is used to adjust the band-switch points to minimize the
frequency difference between the end frequency of one band and the start frequency of the
next higher band. Trim Sweep is not used in the step-sweep mode.
For 8350 sources, trim sweep is adjusted to provide the best frequency accuracy. The trim
sweep setting is saved as part of the instrument state when you press
SAVE,
[INSTRUMENT STATE n]
, and as part of the limited instrument state saved when you save a
calibration set. Trim sweep is set to zero by
[FACTORY PRESET].
NOTE In an extreme case you may need to use the 85102 test set adjustment
software to adjust A20, the 85102 Sweep Board (part number 08510-10024,
Rev A.01.10).
Adjusting the 8340/41 Trim Sweep
If you select ramp sweep mode using an 8340/41 source, set TRIM SWEEP to provide the
minimum frequency difference between the band switch points in ramp mode as follows:
1. Press
RECALL, [MORE], [FACTORY PRESET]. Set S21 for display.
2. Connect measurement PORT 1 to measure PORT 2 (through connection). Press
PHASE.
3. Set the
START, STOP, CENTER, SPAN controls to sweep the frequency range of interest.
4. Press
STIMULUS MENU, [STEP]. When the sweep is complete, press DISPLAY.
5. Press [DATA→MEMORY 1], [MATH (/)]. When the next sweep is complete, the trace should
be a flat line at 0
°.
6. Press
STIMULUS MENU, [RAMP]. The displayed trace may exhibit a sharp phase
transition at the band switch points. Sharp transition indicate the need to adjust trim
sweep.
7. Press
CAL, [MORE], [TRIM SWEEP]. Then use the knob to adjust the phase trace for
minimum phase change at the band switch points. When the best (flattest) phase trace
is achieved, press
SAVE, [INSTRUMENT n] to save this setting. Now proceed with the
appropriate measurement calibration.
Adjusting the 8350 Trim Sweep
Set TRIM SWEEP to provide the best frequency accuracy as follows:
1. Press
RECALL, [MORE], [FACTORY PRESET]. Set S21 for display.
2. Connect measurement PORT 1 to measure PORT 2 (through connection). Press
PHASE.
3. Set the
START, STOP, CENTER, SPAN controls to sweep the frequency range of interest.
4. Press [
DATA→MEMORY 1], [MATH (/)]. When the next sweep is complete, the trace should