Agilent Technologies Infinium DCA 86100A, Service Manual, Page: 43 / 268

3-3
Adjustments
Timebase Adjustment
Timebase Adjustment
The frequency of the 250 MHz oscillator is adjusted with a variable capacitor located on the A13
Acquisition Assembly. The adjustment capacitor can be accessed from a hole in the bottom of
the instrument cover. The adjustment is made so that one cycle of the 250 MHz oscillator
matches the time of the 4 ns ramp.
Software routines built into the DCA firmware make the final adjustments so that the timebase is
accurate across the full range of instrument settings.
N O T E This adjustment should be performed yearly or after every 2,000 hours of operation.
Manual Testing
Table 3-1. Equipment Required for Manual Timebase Adjustment
Equipment
Critical Specifications Recommended Model/Part
Plug-in Module 54750A, 83480A, or
86100A/B Series plug-in
with electrical input Agilent 54751A, 83483A, 86112A
Synthesized CW Generator No substitution Agilent 83712B
Required Options:
1E5 — High Stability Timebase
Recommended Options:
1E1— Output Step Attenuator
1E8 — 1 Hz Frequency Res.
1E9 — 3.5 mm RF Out Connector
Attenuator a
a. not required if 83712B option 1E1 installed
10 or 20 dB;
Frequency range of
dc to 18 GHz
Agilent 33340C
Timing Generator No substitution Agilent 8133A Standard or Option 002
Transition Time Converter 2000 ps Agilent 15438A
Cable, BNC
50
Ω
, 122 cm (48.in)
Agilent 10503A
Adapter, BNC (m) to SMA
(m)
50
Ω
Agilent E9633A BNC (m) to SMA
(m), 50 W
Cable Assembly, 3.5 mm (m)
to 3.5 mm (m) (2 each) 61 cm (24 in); Frequency
range of dc to 26.5 GHz Agilent 11500E