Agilent Technologies N6700 Series User Manual page 54

Programming High-Speed Test Extensions
The Digitizer Function
Programming the Digitizer
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The digitizer function lets you access the enhanced voltage and
current measurement capabilities of the power system. These
include:
Adjusting the measurement sample rate - to a maximum of
50 kHz.
Adjusting measurement triggers to capture pre-trigger transients.
Selecting a measurement window that can attenuate ac noise.
Retrieving arrays that contain the digitized output current or
output voltage.
Synchronizing measurements with either a Bus, Transient, or
external trigger.
Adjust the Measurement Sample Rate
The following figure illustrates the relationship between
measurement samples (or points), and the time interval between
samples in a typical measurement.
TRIGGER
OCCURS
TIME INTERVAL BETWEEN SAMPLES
ACQUISITION TIME
(TIME INTERVAL X #SAMPLES)
Ripple rejection is a function of the number of cycles of the ripple
frequency contained in the acquisition window. More cycles in the
acquisition window results in better ripple rejection. You can vary
the measurement data sampling rate using the following commands:
Front Panel:
Select Measure\Sweep\Points.
Enter a value and press Select.
Then scroll to Time Interval, enter a
value and press Select again.
*The time interval is rounded to the nearest 20.48µs interval, which is 61.44µs.
Acquire 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.
MEASUREMENT
SAMPLE
SCPI Command:
For example, to set the time interval
to 60µs* with 4096 samples, use:
SENS:SWE:TINT 60E-6, (@1)
SENS:SWE:POIN 4096, (@1)
Series N6700 User's Guide