Tektronix CSA7404B User Manual page 216

Measuring Waveforms
Overview To take automatic measurements (Cont.)
Set 18. To select how the instrument determines the base and
top of the waveform, touch Min-Max, Histogram, or
measurement
Histogram mean.
reference
levels (Cont.)
H
H
H
19. To select the reference level units, touch Units Absolute
or Percentage.
H
H
20. To set the reference levels, touch HighRef, Mid Ref, Low
Ref, or Mid2 Ref, and use the multipurpose knobs or
keypad to set the levels.
3- 148
Min-max. Uses the highest and lowest values of the
waveform record. This setting is best for examining
waveforms that have no large, flat portions at a
common value, such as sine waves and triangle
waves — almost any waveform except for pulses.
See Figure 3- - 36 on page 3- - 143.
Histogram. Selects the most common values above
or below the midpoint. Since this approach ignores
short term aberrations (overshoot, ringing, and so
on), Histogram is the best setting for examining
pulses. See Figure 3- - 36 on page 3- - 143.
Histogram mean. Calculates the mean value using
all values either above or below the midpoint
(depending on whether it is defining the high or low
reference level). Histogram mean is best for
examining eye patterns and optical signals.
Absolute. Sets the units to absolute values in user
units.
Percentage. Sets the units as a percentage of the
High/Low range.
CSA7000B Series & TDS7000B Series Instruments User Manual
Related control elements and resources