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O
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M
PERATOR
S
ANUAL
Selecting a Sampling Mode
1. In the menu bar, touch Timebase, then Horizontal Setup... in the drop-down menu.
2. In the Horizontal dialog, touch a Sample Mode button.
3. If you chose Sequence Mode, touch the Smart Memory tab, then touch inside the Num Segments field
and enter a value using the pop-up numeric keypad.
4. If you want to use a timeout condition for Sequence mode, touch the Enable Timeout checkbox; then touch
inside the Timeout field
and enter a value using the pop-up numeric keypad.
Single-shot Sampling Mode
Basic Capture Technique
A single-shot acquisition is a series of digitized voltage values sampled on the input signal at a uniform rate. It is
also a series of measured data values associated with a single trigger event. The acquisition is typically stopped a
defined number of samples after this event occurs: a number determined by the selected trigger delay and
measured by the timebase. The waveform's horizontal position (and waveform display in general) is determined
using the trigger event as the definition of time zero.
You can choose either a pre- or post-trigger delay. Pre-trigger delay is the time from the left-hand edge of the
display grid forward to the trigger event, while post-trigger delay is the time back to the event. You can sample the
waveform in a range starting well before the trigger event up to the moment the event occurs. This is 100% pre-
trigger, and it allows you to see the waveform leading up to the point at which the trigger condition was met and
the trigger occurred. (The instrument offers up to the maximum record length of points of pre-trigger information.)
Post-trigger delay, on the other hand, allows you to sample the waveform starting at the equivalent of 10,000
divisions after the event occurred.
Because each instrument input channel has a dedicated ADC (Analog-to-Digital Converter), the voltage on each
is sampled and measured at the same instant. This allows very reliable time measurements between the
channels.
On fast timebase settings, the maximum single-shot sampling rate is used. But for slower timebases, the
sampling rate is decreased and the number of data samples maintained.
The relationship between sample rate, memory, and time can be simply defined as:
and
Sequence Sampling Mode - Working with Segments
In sequence mode, the complete waveform consists of a number of fixed-size segments acquired in single-shot
mode (see the instrument specifications for the limits). Select the number of segments to be captured, then select
each segment individually and use it for processing with math and measure tools.
Sequence mode offers a number of unique capabilities. With it, you can limit dead time between trigger events for
consecutive segments. The instrument can capture in fine detail complicated sequences of events over large time
intervals, while ignoring the uninteresting periods between the events. You can also make time measurements
between events on selected segments using the full precision of the acquisition timebase.
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