Tektronix 2230 Service Manual

Operating Information—2230 Service
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 0.05 s per division and
faster, 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 after a triggering event. Then the
waveform display is updated with the newly
acquired data in its entirety.
0 ) 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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Tektronix 2230 Specifications

General

Brand	Tektronix
Model	2230
Category	Test Equipment
Language	English