Tektronix CSA7154, Руководство пользователя

Страница: 119 / 480

Acquiring Waveforms
CSA7000 Series, TDS7000 Series, & TDS6000 Series Instruments User Manual
3- 41
The instrument acquisition system can process the data as it is acquired,
averaging or enveloping the waveform data to produce enhanced waveform
records. Once the waveform record exists (enhanced or not), you can use the
postprocessing capabilities of the instrument to further process that record:
perform measurements, waveform math, and so on. Refer to
Using the Acquisi-
tion Controls on page 3--28 for a description of the acquisition modes.
While sampling on the input signal provides the data that makes up the
waveform record for any given channel, the instrument builds the waveform
record through use of some common parameters (“common” means that they
affect the waveforms in all channels).
Figure 3--10 shows how these common parameters define the waveform record;
as shown in the figure, they define where in the data stream and how much data
is taken. Locate the following parameters in the figure:
H
Sample Interval. The time between sample points taken during acquisition.
H
Record Length. The number of samples required to fill a waveform record.
H
Trigger Point. The trigger point marks the time zero in a waveform record.
All waveform samples are located in time with respect to the trigger point.
H
Horizontal Position. If horizontal delay is off, the time lapse from the first
sample taken (first point in the waveform record) to the trigger point (in
percent of samples before the trigger). When horizontal delay is off, the
trigger point and the horizontal reference are at the same point in the
waveform record.
Acquisition Modes
Waveform Record