Table of Contents
Advertisement
Trigger
MODE (29)
- Selects
the
mode of
trigger
operation
as follows:
SINGLE (HOLD) - Selected
using
the
lower
button
(29).
In
this
mode
the
9400A
digitizes
until
a valid
trigger
is
received.
After
the
waveform
has
been
acquired
and
displayed,
no
further
signals
can
be acquired
until
the
SINGLE (HOLD) button
has
been
pressed
again
to
re-arm
the
trigger
circuit
in
preparation
for
the
next
trigger
signal.
This
type
of
acquisition
provides
a
simple
means of recording
a wide
variety
of transient
events.
When the 9400A is in the Random Interleaved Sampling (RIS) mode,
sufficient
number
of triggers
must be obtained
to complete
waveform
reconstruction,
after
which
the waveform
will
be
displayed.
No further signals can be acquired until the SINGLE
(HOLD) button has been pressed again.
When the 9400A is in the Roll mode (~ 500 msec/div), pressing the
SINGLE (HOLD) button causes data acquisition to immediately halt
and the display to freeze.
NORM - Selected
using
button
(29).
When in
the
normal
(NORM) trigger
mode,
the
9400A
continuously
digitizes
the
input
signal.
Whenever
a valid
trigger
is
received,
the
acquired
waveform
is
displayed
on the
CRT, digitization
starts
again
and
the
trigger
circuit
is
re-armed.
If
no subsequent
trigger
is
received
within
2 seconds,
previously
acquired
waveforms
are
erased
from
the
screen.
The absence
of
a valid
trigger
will
thus
result
in a blank
screen.
To retain the last acquired
waveform
indefinitely
in the NORM
mode, the 9400A's Auto-store feature is used. Auto-store can be
called via the Special Modes menu described in Section 5.2.5.
When the 9400A is in the RIS mode, a sufficient number (typically
200) of valid triggers is required for each display of a complete
waveform.
In the Roll mode (~ 500 msec/div), the 9400A samples the input
signals continuously.
Each point is immediately
updated on the
display. This results in a trace which moves from right to left
across the CRT. In the NORM mode, triggers are ignored. The only
way to halt data acquisition is to select the SINGLE (HOLD) mode
or switch the 9400A into AUTO mode and provide a trigger.
5-9
Manual Operation
Advertisement
Table of Contents
