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6 Advanced Source and Measurement Functions
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OFFSET = -524,287
TIME
NOTE
164
Capture Pre-trigger Data
The measurement system lets you capture data before, after, or at the
trigger signal. As shown in the following figure, you can move the
block of data being read into the acquisition buffer with reference to
the trigger. This allows pre- or post-trigger data sampling.
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OFFSET = -262,144
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OFFSET = 0
OFFSET = 0 to 2E9
TRIGGER
The following command offsets the beginning of the acquisition
buffer relative to the trigger by 100 points on channel 1:
SENS:SWE:OFFS:POIN 100,(@1)
When the value is 0, all values are taken after the trigger. Values
greater than 0 can be used to program a delay time from the receipt
of the trigger until the values entered into the buffer are valid. (Delay
time = offset x sample period). Negative values let you acquire
samples prior to the trigger.
If, during a pre-trigger data acquisition, a trigger occurs before the pre-trigger
data count is completed, the measurement system ignores this trigger. This will
prevent the completion of the measurement if another trigger is not generated.
Specify a Window Function
Windowing is a signal conditioning process that reduces the error in
average measurements made in the presence of periodic signals and
noise. Two window functions are available: Rectangular and
Hanning. At power-on, the measurement window is RECTangular.
The Rectangular window calculates average measurements without
any signal conditioning. However, in the presence of periodic signals
such AC line ripple, a Rectangular window can introduce errors
when calculating average measurements. This can occur when a non-
integral number of cycles of data has been acquired due to the last
partial cycle of acquired data.
524,288 DATA POINTS
Model N6705 User's Guide
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