3-8
SWEEP FREQUENCY
OPERATION
The sweep generator can generate broad (full range) and narrow band
sweeps across the frequency range of the instrument. The 681XXA has
three sweep frequency modes—analog sweep, step sweep, and manual
sweep. The following paragraphs describe how to select each sweep fre-
quency mode, a sweep range, an output power level, a sweep trigger,
and frequency markers. Use the Analog Sweep, Step Sweep, and Man-
ual Sweep Frequency Mode menu maps (Chapter 4, Figures 4-3, 4-4,
and 4-5) to follow the menu sequences.
Selecting
Analog
Sweep Mode
In analog sweep frequency mode, the sweep gener-
ator’s output frequency is swept between selected
start and stop frequencies. When the sweep width is
>50 MHz, the sweep is phase-lock corrected at both
the start and stop frequencies and at each band-
switch point. When the sweep width is
≤
50 MHz,
only the center frequency of the sweep is phase-lock
corrected.
To place the 681XXA in analog sweep frequency
mode, press the main menu key
CW/SWEEP
SELECT
At the resulting menu display, press
Analog
. The
Analog Sweep Menu (shown below) is then dis-
played.
This menu lets you perform the following:
Select a sweep range (edit the sweep start and
stop frequency parameters).
Go to the sweep ramp menu (set the sweep
time and select a sweep trigger).
Select a marker mode.
Go to the alternate sweep menu.
LOCAL (FRONT
SWEEP FREQUENCY
PANEL) OPERATION
OPERATION
3-22
681XXA OM
