Chapter 2 191
Front-Panel Key Reference
Sweep
Sweep
Single Cont
Switches the analyzer between the continuous-sweep mode and the
single-sweep mode. Pressing
Sweep (Single) puts the analyzer in
single-sweep mode. Press
Single on the front panel, to enable a sweep
when in single-sweep mode. When
Sweep (Cont) is selected, one sweep
follows another as soon as it is triggered. Pressing
Preset (When Preset
Type
is set to Factory) or turning the power on, sets the sweep mode to
continuous sweep.
Key Access:
Sweep
Auto Swp
Coupling
SR SA
Selects stimulus-response (SR) or spectrum-analyzer (SA) (default)
auto-coupled sweep times. In stimulus-response mode, auto-coupled
sweep times are usually much faster for swept-response measurements.
Stimulus-response auto-coupled sweep times are typically valid in
stimulus-response measurements when the system’s frequency span is
less than 20 times the bandwidth of the device under test.
Key Access:
Sweep
Gate
Requires Option 1D6 (Time Gate). Accesses the following menu keys
that allow you to setup various gate parameters:
Key Access:
Sweep
Gate On Off
Requires Option 1D6 (Time Gate). Turns the gate
function on and off. When set to
Gate (On), the video
signal that is digitized is controlled by the gate
circuitry. The gate circuitry switches between two
states. When the gate is “open”, the normal video signal
of the analyzer is passed through the video filters to the
peak detectors and digitizer of the analyzer. When the
gate is “closed”, the video filters, peak detectors, and
digitizer are given a signal at the bottom of the display.
The gate function requires that a gate trigger signal be
connected to the
GATE TRIG/EXT TRIG IN (TTL) input on
the rear panel. When the gate function is on, the state
of the gate appears at the GATE/HI SWP OUT (TTL) rear
panel connector. A TTL high output indicates that the
gate is open. The gate out signal is only valid while the
analyzer is sweeping. Between sweeps, the gate out
signal is invalid. You can adjust the gate delay and gate
length using an oscilloscope to view the gate out signal.
The analyzer sweep time should be set to a large value
(50 sec) during the adjustment so that the gate signal is
valid most of the time. When the adjustment is done
you can set the analyzer back to the desired sweep
time, or set it back to
Auto Couple.
Key Access:
Sweep, Gate