Tektronix DSA8300, Programmer'S Manual

Page: 268 / 455

Commands Listed in Alphabetical Order
NOTE.
The SOURCE<x> argument speci fi es the source, which can be source 1
or source 2. To set the actual waveform (channel, reference, or math) that is
assigned to source, you must use the MEASUrement:MEAS<x>:SOURCE<x>
WFM command. Two sources are provided because some measurements (gain,
phase) require two sources.
Group
Measurement
Syntax
MEASUrement:MEAS<x>:SOUrce<x>:HILow:METHod {AUTO | MODE |
MINMax | MEAN}
MEASUrement:MEAS<x>:SOUrce<x>:HILow:METHod?
Arguments
AUTO
attempts to use the most appropriate method of calculating the high
and low values for the speci fi ed signal type. If the signal type is set to Eye,
the instrument defaults to the Mean method of calculating the high and low
values. If the signal type is set to Pulse, the instrument defaults to the Mode
method of calculating the high and low values. However, the instrument will
automatically switch to the Min/Max method if the histogram used to track
the high and low values does not show an obvious consistent high level or to
the Mean method if the histogram shows at least two different concentrations
of peak values. For example, the Mode histogram operating on a triangle
wave would not
fi nd signi fi cant high and low levels, and the instrument would
switch to the Min/Max mode. On a square wave, the Auto mode would use
the Mode method to calculate the high and low values.
MODE
attempts to fi nd, using a histogram, the highest density of points above
and below the waveform midpoint. see fi gure below. It attempts to ignore
ringing and spikes when determining the 0% and 100% levels. This method
works well when measuring square waves and pulse waveforms.
MINMax
de fi nes the 0% and 100% waveform levels as the lowest amplitude
(most negative) and the highest amplitude (most positive) samples. See
the
fi gure below. This method is useful for measuring frequency, width,
and period for many types of signals. However, this method is sensitive to
waveform ringing and spikes and does not always accurately measure rise
time, fall time, overshoot, and undershoot.
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