Tektronix 2230, Service Manual

Page: 62 / 483

Operating Information— 2230 Service
STORAGE CONTROLS
See Figure 2-8 for the location of items 38 through 42.
(
3 9
) STORE/NON STORE Switch— Selects either the
' ' NON STORE or the STORE waveforms for display.
The STORE acquisition system is turned off while
NON STORE is selected, keeping the last-acquired
STORE waveform in memory. Selects NON STORE
when out and STORE when pressed in.
(
4 0
) ACQUISITION Controls— Determine the method of
acquiring and displaying the acquired STORE
waveform.
1K/4K Switch (Record Length)— Selects an
acquisition record length of either one screen (1K)
or four screens (4K). Pressing the button in
selects 1K record length, and pressing it again to
release it returns to 4K record length acquisitions.
In either case, the displayed waveform has 100
data points per horizontal graticule division (50 if
two channels are acquired).
When a waveform is acquired using the B time
base, switching between record lengths also
changes the delay time position setting by the
same factor of four. The B DELAY TIME POSI­
TION control must be repositioned to obtain the
same delay.
When the 4K record length is selected, a one-
screen (1K) window of the acquisition is
displayed, and a bar graph is used to indicate the
position of the displayed window within the
record. Turn the CURSORS Position control to
move the display window to any position within
the record.
The 4K acquisition record can be compressed to
a length of IK by rotating the Variable SEC/DIV
control out of the CAL detent position. The
SEC/DIV readout is adjusted to reflect the correct
time per division of the displayed waveform. The
acquisition record may be magnified using the
X I0 Magnifier.
PRETRIG/POST TRIG Switch— Positions the
trigger point for acquisitions either near the end
(PRETRIG) or the beginning (POST TRIG) of the
waveform. A T is displayed on the waveform to
indicate the trigger point. Pressing the button in
sets the trigger point to PRETRIG; out is the
POST TRIG position.
ROLL/SCAN Switch— Selects either ROLL or
SCAN acquisition and display mode. When
pressed in (ROLL mode), at SEC/DIV switch set­
tings from 0.1 s per division to 5 s per division the
triggers are disabled for NORM and P-P AUTO
Trigger modes, and the signals are continuously
acquired and displayed. The waveform display
scrolls from right to left across the crt -with the
latest samples appearing at the right edge of the
crt. At SEC/DIV switch settings from 0.1 s per
division to 5 s per division in SGL SWP Trigger
mode, SCAN/ROLL/SCAN storage mode is
selected.
At SEC/DIV switch settings of 0.05 s per division
and faster, the ROLL/SCAN switch is not func­
tional, and waveform samples require a triggering
event to complete the acquisition before the
display is updated.
When the ROLL/SCAN switch is in the out posi­
tion (SCAN mode), the A TRIGGER Mode con­
trols are functional. For NORM Trigger mode, the
pretrigger waveform is updated by the trigger and
the post trigger scans from the trigger position to
the right. For SGL SWP, SCAN mode is overrid­
den by SCAN/ROLL/SCAN. Triggers are disabled
in P-P AUTO and TV FIELD Trigger modes.
2-15
Figure 2-8. Storage controls.