Ac Rms - Agilent Technologies InfiniiVision 4000 X-Series User Manual

14
Measurements
The N Cycles measurement interval variation measures the value on an
integral number of periods of the displayed signal. If less than three edges
are present, the measurement shows "No edges".
The X cursors show the interval of the waveform being measured.

AC RMS

AC RMS is the root- mean- square value of the waveform, with the DC
component removed. It is useful, for example, for measuring power supply
noise.
The N Cycles measurement interval measures the value on an integral
number of periods of the displayed signal. If less than three edges are
present, the measurement shows "No edges".
The X cursors show the interval of the waveform being measured.
The Full Screen (Std Deviation) measurement interval variation is an RMS
measurement across the full screen with the DC component removed. It
shows the standard deviation of the displayed voltage values.
The standard deviation of a measurement is the amount that a
measurement varies from the mean value. The Mean value of a
measurement is the statistical average of the measurement.
The following figure graphically shows the mean and standard deviation.
Standard deviation is represented by the Greek letter sigma:
Gaussian distribution, two sigma (± 1 ) from the mean, is where 68.3
percent of the measurement results reside. Six sigma (± 3 ) from is where
99.7 percent of the measurement results reside.
252 Agilent InfiniiVision 4000 X-Series Oscilloscopes User's Guide
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