Tektronix 071-0957-03, User Manual

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Measure
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TDS3000B Series User Manual
High-Low Setup. The oscilloscope determines the 10%, 50%, or 90%
levels of the waveform and then uses them to calculate the
measurements. You can choose the method used to determine these
levels:
H
Histogram sets the values statistically; it finds the most common
value either above or below the midpoint (depending on whether
it is defining the high or low reference level). Since this
statistical approach ignores short-term aberrations (overshoot,
ringing, noise), histogram is the best method for measuring
digital waveforms and pulses.
H
Min-max uses the highest and lowest values of the waveform
record. This method is best for measuring waveforms that have
no large, flat portions at a common value, such as sine waves and
triangle waves.
H
Auto Select chooses one of the above methods automatically
depending on the signal characteristics. Auto Select chooses the
histogram method if the histogram contains prominent peaks. If
not, Auto Select chooses the min-max method.
Measurement Gating. You can use the gating feature to limit
measurements to the portion of the waveform that is on the screen or
between the cursors.
When you turn Screen gating on, the oscilloscope only uses the
waveform points on screen in its measurements. This function is
useful at the fastest time base settings or when you want to take
measurements on a magnified waveform (when zoom
is on).
When you turn Cursor gating on, the oscilloscope displays vertical
bar cursors. Use the general purpose knob and SELECT button to
place the cursors around the area of interest.