Example 10: Creating A Histogram Display - Tektronix 11801C User Manual

Example 10: Creating a Histrogram Display
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In Example 4, you used color grading to view the relative density of trace
points in a display of this signal. A histogram will provide additional statisti
cal information about the distribution of points in the trace.
Step 9: Press the DISPLAY MODES button and select Persist/Histo
grams in the major menu area.
Step 10: Select Vertical Histogram in the pop up menu, and then
select Exit.
When you selected Vertical Histogram, the display persistence automatical
ly changed from Normal to Infinite. Histograms can be displayed on traces
in the infinite persistence and color grading display modes, but not in nor
mal or variable persistence modes.
The histogram display appears in red along the right side of the graticule. A
red box on the graticule outlines the limits of the histogram data; trace data
that fall outside these limits are ignored.
The amount of noise you see in the displayed signal will depend on the
sampling head you have installed. The illustration in Figure 2 52 shows the
calibrator signal as acquired using an SD 24 sampling head. If you are using
a lower noise sampling head, such as the SD 22, you will see less noise on
the display.
The major menu area shows readouts for the histogram parameters and
results:
H Top, Btm, Lft, and Rgt are the limits of the histogram data (displayed as
a red box).
H Mean is the mean vertical value of the trace data within the histogram
limits.
H RMSD is the root mean square deviation, or standard deviation, of trace
data points from the Mean value.
H PkPk is the peak to peak measurement of the trace within the histogram
limits.
H Hits is the number of trace data points that fall within the histogram
limits.
H Wfms is the number of traces (waveforms) acquired for the histogram.
H 1 is the percentage of points that are within one standard deviation
(s) of the mean (m).
fall within two standard deviations and three standard deviations, re
spectively, of the mean.
2 and 3 are the percentages of points that
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