Making Automatic Measurements From The Front Panel - HP 54710A User's Reference Manual

Measurements

Making Automatic Measurements from the Front Panel

Making Automatic Measurements from the Front
Panel
The oscilloscope makes its measurements using the data showing on the
display. It is therefore important that you correctly window the display to get
accurate measurements. Windowing allows you to pick one pulse out of a
series of pulses to make measurements on.
If more than one waveform, edge, or pulse is displayed, automatic
measurements are made on the first (leftmost) portion of the displayed
waveform that can be used.
When making measurements on non symmetrical waveforms, expand the
signal as necessary and move the baseline out of the window. This will avoid
having the baseline selected as the top of the signal.
If the signal is clipped, the oscilloscope cannot make some automatic
measurements. You will get a warning or error message if this occurs.
Period and Frequency Measurements
At least one full cycle of the waveform, with at least two like edges, must be
displayed for period and frequency measurements.
Additionally, you can increase the accuracy of frequency measurements by
windowing on multiple pulses. Automatic waveform measurements use a
single pulse and may have significant errors introduced by interpolation and
trigger inaccuracies. By placing marker 1 on edge 1 and marker 2 on edge
20, for example, you can get an average that negates errors that may be
introduced in automatic measurements. This becomes even more important
when using the deep memory feature of the oscilloscope.
Set the markers to accomplish average frequency measurements from the
front panel by using the ∆t measurement in the define measure menu.
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