Measuring Waveforms
3–88
TDS 684A, TDS 744A, & TDS 784A User Manual
Automatic measurements are taken over the entire waveform record or, if you
specify gated measurements (see page 3–91), over the region specified by the
vertical cursors. Automated measurements are not taken just on the displayed
portions of waveforms.
The oscilloscope can also display almost all of the measurements at once — see
Take a Snapshot of Measurements on page 3–95.
The TDS Oscilloscope provides you with 25 automatic measurements in three
categories: amplitude (typically in volts; sometimes in %), time (typically in
seconds or hertz), and area (in volt-seconds). Table 3–9 lists brief definitions of
the automated measurements in the oscilloscope (for more details see Appen-
dix B: Algorithms, page B–1).
Table 3–9: Measurement Definitions
Name Definition
Amplitude Voltage measurement. The high value less the low value measured over the entire waveform or
gated region.
gated region.
Amplitude = High – Low
Area Voltage over time measurement. The area over the entire waveform or gated region in
volt-seconds. Area measured above ground is positive; area below ground is negative.
Cycle Area Voltage over time measurement. The area over the first cycle in the waveform, or the first cycle
in the gated region, in volt-seconds. Area measured above ground is positive; area below
ground is negative.
Burst Width Timing measurement. The duration of a burst. Measured over the entire waveform or gated
region.
Cycle Mean Voltage measurement. The arithmetic mean over the first cycle in the waveform or the first cycle
in the gated region.
Cycle RMS Voltage measurement. The true Root Mean Square voltage over the first cycle in the waveform
or the first cycle in the gated region.
Delay Timing measurement. The time between the MidRef crossings of two different traces or the
gated region of the traces.
Fall Time Timing measurement. Time taken for the falling edge of the first pulse in the waveform or gated
region to fall from a High Ref value (default = 90%) to a Low Ref value (default =10%) of its
final value.
Frequency Timing measurement for the first cycle in the waveform or gated region. The reciprocal of the
period. Measured in Hertz (Hz) where 1 Hz = 1 cycle per second.
High The value used as 100% whenever High Ref, Mid Ref, and Low Ref values are needed (as in fall
time and rise time measurements). Calculated using either the min/max or the histogram method.
The min/max method uses the maximum value found. The histogram method uses the most
common value found above the mid point. Measured over the entire waveform or gated region.
Measurement List
