Acquiring Waveforms
3-22 CSA8000B & TDS8000B User Manual
Envelope acquisition mode can not be used with FrameScan acquisitions; you
must use Sample or Average modes.
The key points that follow describe operating considerations for setting up the
acquisition system so the waveforms acquired best fit your requirements.
Acquisition Modes. Consider the mode you want to use to acquire data:
HSample - the instrument does no post-processing of acquired samples.
HAverage - the instrument processes the number of waveforms you specify
into the acquired waveform, creating a running exponential average of the
input signal.
HEnvelope - the instrument retains the running minimum (Min) and maximum
(Max) values in adjacent sample intervals continuously, as subsequent
waveforms are acquired, creating an envelope of all waveforms acquired for
that channel.
Acquiring and displaying a noisy square wave signal illustrates the difference
between the three modes. Note how Average reduces the noise while Envelope
captures its extremes:
Sample Envelope
Average
Acquisition Control. Also, consider how you want to control acquisition; you
have two main options, either settable from the Acquisition Setup dialog box
(push Acquisition MENU to display):
HRun/Stop Button Only - sets the instrument to start and stop the acquisition
only when you use the Run/Stop button, which is available on the front
panel, on the application toolbar, and in the Acquisition Setup dialog box. If
toggled to Run, acquisition will start if a valid trigger occurs. If toggled to
Stop, acquisition stops immediately.
HCondition - in addition to Run/Stop Button, which can always stop
acquisition, the stop-after control provides additional conditions you can
select from to stop an acquisition. See step 4, Set the Stop Mode and Action,
on page 3--25, or access the online help in the Acquisition Setup dialog box
for more information.
What’s Excluded?
Keys to Using