--
enough that the acquisition can manually
be
stopped when events
of
interest
are
observed.
P-P AUTO
is
selected. P-P AUTO provides a
baseline
in
the absence
of
triggers from the
input signal. The circuit considers the absence
of
triggers to
be
about half
of
a second without
a trigger. Below
50
ms per division, the
triggers are prevented for longer than that
by
the sweep time itself, therefore triggers are
ignored.
TRIGGERED mode performs triggered
acqu1s1-
tions
in
STORE mode at SEC/DIV settings of 5 s
per division to
0.1
s per division when triggers
can
be
meaningful. Triggers
are
meaningful
in
SCAN mode if the A TRIGGER mode
is
NORM or
SGL SWP. Triggers are not meaningful
in
ROLL
mode or
in
the A TRIGGER Mode of
P-P
AUTO.
REPETITIVE Store mode
(2
µs/div to
0.05
µs/div)
requires a repetitive trigger signal. Sampling
occurs at the maximum A/D conversion rate. If a
control affecting
an
acquisition parameter or func-
tion is changed, the acquisition is reset,
and
the
waveform being acquired is cleared
on
the next
sample acquired.
On
each valid trigger, 10 or
more equally spaced samples
are
acquired
and
displayed
on
the waveform record, depending
on
the SEC/DIV setting
(see
Table
3-3).
The random
time delay from the trigger to the following sam-
ple clock transition
is
measured
by
the Clock
Delay Timer circuit
and
used to place the acquired
waveform samples
in
the correct display memory
location. Any display location
is
equally likely to
be filled. Table
3-3
gives the statistically expected
number of trigger events required to completely
fill the display, assuming a uniform distribution of
trigger events relative to the sample interval.
FAST RECORD Storage mode
(5
µs/div to
10 µs/div) updates a full record of the acquired
waveform.
SLOW RECORD Storage mode
(20
µs/div to
50
ms/div) updates a full record of the acquired
waveform.
SCAN Storage mode (for NORM TRIGGER mode
and
0.1
s/div to 5 s/div or EXT CLOCK) updates
pretrigger data when a trigger
is
received. The
waveform display then scans to the right from the
trigger point to finish the post-trigger acquisition
and then freezes.
Controls, Connectors, and
lndicators-2230
Operators
SCAN Storage mode (for
P-P
AUTO TRIGGER
mode with auto triggers disabled
and
0.1
s/div to
5 s/div or EXT CLOCK) continuously updates the
display serially
as
each data point
is
acquired. It
writes over previous data from left to right.
ROLL Storage mode (P-P AUTO TRIGGER mode
and
0.1
s/div to 5 s/div or EXT CLOCK) continu-
ously acquires and displays signals. Triggers
are
disabled. The waveform display scrolls from right
to left across the crt with the latest samples
appearing at the right edge of the crt.
SCAN-ROLL-SCAN Storage mode (SGL SWP
TRIGGER mode
and
0.1
s/div to 5 s/div or EXT
CLOCK) serially updates the display. The
waveform display SCANS left to right until the
pretrigger record
is
filled, and
then_
ROLLS right
to left until a trigger is received. It then SCANS
left to right again to fill the post-trigger acquisition
record
and
then freezes
(see
SGL SWP descrip-
tion for further details).
PEAKDET Acquisition mode digitizes
and
stores,
in
acquisition memory
as
a data pair, the
minimum and maximum levels
of
the input signal
within the time represented
by
1/50
of a division
UN-MAG
(1/25
division
in
CHOP or ALT).
SAMPLE samples the signal at a rate that pro-
duces
100
samples per graticule division.
In
the
RECORD Sampling modes, the displayed sample
points are displayed
by
vectors or dots. For
REPETITIVE Store mode, the sample points are
displayed
as
dots.
Table 3-3
Repetitive Store Sampling Data Acquisition
SEC/DIV Samples Per
Expected
Switch
Acquisition Acquisitions
Setting
Per Waveform
8
1K
4K
1 2
Mode
Mode
Channel Channels
0.05
µS
10
40
519
450
0.1
µS
20
80
225
191
0.2
µS
40
160
96
83
0.5
µS
100
400
30
23
1
µS
200
800
12
11
2
µS
200
800
12
11
8
Expected acquisitions per waveform for a 50% probability
of
fill.
3-7
To Next Page
Loading...
Need help?
General
