B&K Precision 2552-2559 - Manual - Manual (Page 73)

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• “RUN/STOP” Button: Press the RUN/STOP button when you
want the oscilloscope to acquire waveforms continuously. Press
the button again to stop the acquisition.
• “SINGLE” Button: Press the SINGLE button to acquire a single
waveform. Each time you push the SINGLE button, the
oscilloscope begins to acquire another waveform. After the
oscilloscope detects a trigger it completes the acquisition and
stops.
When you push the RUN/STOP or SINGLE buttons to start an
acquisition, the oscilloscope goes through the following steps:
1. Acquire enough data to fill the portion of the waveform
record to the left of the trigger point. This is also called the
pre-trigger.
2. Continue to acquire data while waiting for the trigger
condition to occur.
3. Detect the trigger condition.
4. Continue to acquire data until the waveform record is full.
5. Display the newly acquired waveform.
• Time Base: The oscilloscope digitizes waveforms by acquiring
the value of an input signal at discrete points. The time base
allows you to control how often the values are digitized. To adjust
the time base to a horizontal scale that suits your purpose, use the
Time/div knob.
• Time Domain Aliasing: Aliasing occurs when the oscilloscope
does not sample the signal fast enough to construct an accurate
waveform record. When this happens, the oscilloscope displays a
waveform with a frequency lower than the actual input waveform,
or triggers and displays an unstable waveform.
Sampled points
Apparent low-frequency
waveform due to aliasing
Actual high-frequency waveform
Figure 42 - Time Domain Aliasing