Controls, Connectors, and
lndicators-2230
Operators
3-10
NORM-Permits triggering at
all
sweep rates
(an
autotrigger
is
not generated
in
the absence of
an
adequate trigger signal). NORM Trigger mode
is
especially useful for low-frequency
and
low-
repetition-rate signals.
In
STORE mode, the last acquired waveform
is
held on display between triggering events. The
pretrigger portion of the acquisition memory
is
continually acquiring new pretrigger data until a
trigger event occurs. How the waveform display
is
updated after the trigger occurs, depends
on
the
SEC/DIV setting. From 5 s per division to
0.1
s
per division, the pretrigger portion of the
displayed waveform
is
updated
by
the pretrigger
data
in
the acquisition memory, then the post-
trigger data points
are
placed
in
the display
as
they are acquired. For faster sweep speeds, the
post-trigger data points are acquired
in
the
acquisition memory prior to completely updating
the waveform display, using the newly acquired
data.
P-P
AUTO-TV
LINE-In
NON
STORE mode,
triggering occurs
on
trigger signals having ade-
quate amplitude
and
a repetition rate of about
20
Hz
or faster.
In
the absence of a proper trigger
signal,
an
autotrigger
is
generated,
and
the sweep
free runs.
In
STORE mode, for SEC/DIV settings of 5 s per
division to
0.1
s per division, the
P-P
AUTO
trigger mode
is
disabled,
and
the acquisition free-
runs. At faster SEC/DIV settings, triggered
acquisitions occur under the same conditions
as
NON
STORE mode
P-P
AUTO triggering,
and
the
acquisition free-runs if proper triggering conditions
are not met. The manner
in
which the display
is
filled
and
updated
is
the same
as
for NORM
triggering.
For either
NON
STORE or STORE mode, the
range of the A TRIGGER LEVEL control
is
automatically restricted to the peak-to-peak limits
of the trigger signal for ease
in
obtaining trig-
gered displays
and
acquisitions.
P-P
AUTO
is
the
usual Trigger mode selection to obtain stable
displays of TV
Line
information.
TV
FIELD-Permits
stable triggering
on
a televi-
sion field (vertical sync) signal when the
P-P
AUTO
and
the NORM Trigger buttons are
pressed
in
together.
In
the absence of
an
ade-
quate trigger signal, the sweep (or acquisition)
free-runs. The instrument otherwise behaves
as
in
P-P AUTO.
@
SGL
SWP-Arms
the A Trigger circuit for a single
sweep
in
NON
STORE or a single acquisition
in
STORE. Triggering requirements are the same as
in
NORM Trigger mode. After the completion of a
triggered
NON
STORE sweep or a STORE SGL
SWP acquisition, pressing
in
the SGL SWP but-
ton rearms the trigger circuitry to accept the next
triggering event or start the next storage acquisi-
tion.
In
STORE mode, when the SGL SWP
is
armed,
the acquisition cycle begins, but the READY
LED
does not come
on
until the pretrigger portion
of
the acquisition memory
is
filled. At the time the
READY
LED
comes on, the acquisition system is
ready to accept a trigger. When a trigger event
occurs, the post-trigger waveform data
is
stored
to complete the single-sweep acquisition. After
the acquisition
is
completed, the READY LED
goes out,
and
the single sweep
can
be
rearmed.
The SEC/DIV switch setting
and
the STORE
mode determine how the display
is
updated. For
settings of 5 s per division to
0.1
s per division, a
storage process known
as
SCAN-ROLL-SCAN is
used. The last acquired waveform
is
erased when
SGL SWP
is
armed, then the pretrigger acquisi-
tion scans from the left edge to the trigger posi-
tion. At that point, the pretrigger portion of the
display
is
rolled left from the trigger position until
a triggering event occurs. Upon receiving
an
ade-
quate trigger, the post-trigger portion of the
display scans from the trigger point to the right
until the remaining data points are filled,
and
then
the display freezes.
For SEC/DIV settings of 50
ms
to 5
µS
(RECORD
store mode}, the display
is
updated
as
a full
record. The previously displayed waveform
remains
on
the crt until the post-trigger portion of
the acquisition memory
is
filled. The waveform
display
is
then updated with the newly acquired
data
in
its entirety. For SEC/DIV settings of 2
µs
to 0.05
µs
(REPETITIVE store mode), a partial
record
is
acquired
each
time the SGL SWP
button
is
RESET, overlaying the samples
accumulated from past acquisitions.
READY-TRIG'D
Indicator-A
dual-function
LED
indicator.
In
P-P
AUTO
and
NORM Trigger modes,
the
LED
is
turned
on
when triggering occurs.
In
SGL
SWP Trigger mode, the
LED
turns
on
when the A
Trigger circuit
is
armed, awaiting a triggering event,
and
turns off again after the single sweep (or
acquisition) completes.
In
STORE mode, pressing the SGL SWP button to
arm
the trigger circuitry does not immediately turn
on
the READY
LED.
The pretrigger portion of the
acquisition memory starts filling after the SGL SWP
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