Tektronix TDS5000B Series, Online Help Manual

Page: 166 / 420

166
Histogram Control Window
Access this control window from the Measure menu Waveform Histograms command.
Overview
Use the Histogram control window to set up a vertical or horizontal histogram. Use vertical
histograms to measure signal noise and horizontal histograms to measure signal jitter.
To Use
Use the Channel Selector tabs to select the source waveform for the histogram measurements.
Next, click the type of histogram that you want to use for your measurement, Horiz (Horizontal) or
Vert (Vertical). Once you make this selection, histograms continue to be calculated even if you set
Display to Off. You must explicitly click the Histogram Mode Off button to stop accumulating
histogram data. Or, click Reset to start a new histogram.
Click either Linear or Log to set the scaling. Adjust the size of the histogram box by clicking
Limits under Adjust Histogram Box, and use the multipurpose knobs to set the box boundaries.
Move the location of the histogram box by clicking Location under Adjust Histogram Box, and
then use the multipurpose knobs to set the X and Y Locations.
Behavior
A histogram consists of a series of narrow bins into which samples are counted. The histogram
box defines the graticule area of the histogram and the number of vertical or horizontal bins.
Horizontal histograms have a maximum of 500 bins while vertical histograms have a maximum of
200 bins.
The displayed width or height of the bin that contains the most counts is determined by the Histo
Size control. The relative sizes for all other bins are scaled proportionally to the bin that contains
the most counts.
Histogram limits use the same units as the horizontal and vertical scale controls. When you
specify the histogram box in terms of location, the Y location control adjusts the bottom edges of
the histogram while the X location control adjust the left edge of the histogram box.
Here are several tips for using histograms:
ƒ
Right-click in the Histogram box to access a shortcut menu that will allow you to quickly
make changes to the histogram.
ƒ
Use the Measure menu or shortcut menu
Reset Histogram
command to reset all bin counts
to 0.
ƒ
Click, hold, and drag across part of the graticule where you want to set up a histogram and
select Histogram from the shortcut menu.
ƒ
Use the same click, hold, and drag method to remove a histogram from the display. Select
Histogram Off from the shortcut menu.
ƒ
You can turn the histogram display off and still accumulate histogram data. This enables you
to view the waveform without having the histogram obscure the data. Turn the histogram
display on (use the Display button on the right side of the control window) at any time to view
the histogram.