User`s guide

Measurements and Math Functions 6
InfiniiVision Oscilloscopes User’s Guide 207
Maximum
Maximum is the highest value in the waveform display. The Y cursor shows the value
being measured.
Minimum
Minimum is the lowest value in the waveform display. The Y cursor shows the value being
measured.
Peak-Peak
The peak-to-peak value is the difference between Maximum and Minimum values. The Y
cursors show the values being measured.
Ratio
The Ratio measurement displays the ratio of the AC RMS voltages of two sources,
expressed in dB. Press the Settings softkey to select the source channels for the
measurement.
RMS
RMS (DC) is the root-mean-square value of the waveform over one or more full periods. If
less than one period is displayed, RMS (DC) average is calculated on the full width of the
display. The X cursors show what interval of the waveform is being measured.
Std Deviation
The Std Deviation measurement shows the standard deviation of the displayed voltage
values. It is an RMS measurement across the full screen with the DC component
removed. It is useful, for example, for measuring power supply noise.
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) =
x
i
2
i 1=
n

n
----------------
where x
i
= value at ith point being measured
n = number of points in measurement interval