HP 54645A User's And Service Manual page 288

Softkeys set up various options
for major functions. The softkeys
change depending on the function
you select. Some softkeys have an
immediate action, and others allow
you to scroll through a list of
choices. Some softkeys are labeled
with two choices below; the high-
lighted choice is currently active.
When several softkeys are displayed
with a labeled bar over them, they
are either related, or the choices are
mutually exclusive.
Source allows you to select a trig-
ger source.
Status indicators are at the top
line of the display and show chan-
nels turned off, the sampling
interval, glitch mode, delay, time
base setting, trigger condition, and
acquisition mode.
Stop freezes the display.
STOP indicator is displayed at
the right end of the status line when
the acquisition has been stopped.
Storage keys control start and
stop of acquisition, persistent acqui-
sition, and screen erasure.
STORE indicator is displayed at
the right end of the status line when
Autostore is selected.
Time allows access to the automat-
ic time measurement keys.
Time/Div changes the time base in
a 1-2-5 step sequence from 2 ns to
50 s (for HP 54645A) and from 5 ns
to 50 s (for HP 54645D).
Time Ref sets the time reference
to either one graticule in from the
left or right edge of the display, or to
center of the display.
Trace allows access to the trace
storage keys.
Trace Mem (trace memory) refers
to one of two pixel memory locations
used for storing traces. If you use
the Measurement/Storage module,
additional trace memories are avail-
able.
Trace memory is also called pixel
memory. Trace memories allow you
to save the visible portion of the ac-
quisition (the displayed waveform)
for later recall and comparison with
other measurements. Trace memory
is normally volatile. However, adding
an interface module makes the trace
memory non volatile. Trace memory
also saves the current configuration,
separate from the 10 setup memo-
ries.
Glossary
Glossary-9