Tektronix CSA7154, Руководство пользователя

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Acquiring Waveforms
CSA7000 Series, TDS7000 Series, & TDS6000 Series Instruments User Manual
3- 23
H
Applying a negative offset moves the vertical range down relative to the DC
level of the input signal. Likewise, applying a positive offset moves the
vertical range up. See Figure 3--3.
Offset 0.0 V
(At waveform ground reference)
300 mV
(Near waveform top level)
Vertical Window = 100 mV (8 divs X 10 mV /div + (+/- 1 divs of position))
Acquisition window shifts
positive to capture overshoot
Acquisition window shifts
negative to capture preshoot
Offset --300 mV
(Waveform bottom level)
Figure 3- 3: Varying offset moves the vertical acquisition window on the waveform
Horizontal Acquisition Window Considerations.
The instrument lets you define the
horizontal acquisition window, that is, set several parameters that determine the
segment of an incoming signal that becomes the waveform record when
acquired. (For background, read
Waveform Record on page 3--41.) These
common parameters specify a horizontal acquisition window that is applied to all
channels in parallel. (See
Independent vs. Shared Window on page 3--26.) These
parameters are:
H
The trigger condition that you set up determines the point on the waveform
that triggers the instrument.
H
Horizontal position also determines the number of pretrigger and posttrigger
samples; samples before the reference point are pretrigger samples and those
after the reference are posttrigger samples.