Agilent Technologies InfiniiVision 3000 - DC Rms; Ac Rms

Measurements 14
Agilent InfiniiVision 3000 X-Series Oscilloscopes User's Guide 223
DC RMS
DC RMS is the root- mean- square value of the waveform over one or more
full periods.
Where x
i
= value at ith point being measured, n = number of points in
measurement interval.
The Full Screen measurement interval variation measures the value on all
displayed data points.
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.
RMS (dc) =
∑
i=1
n
x
i
2
n