HP 54520 Series Service Manual page 56

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Chapter 3: Testing Performance
To test time measurement accuracy
Press Autoscale_, then set the following parameters. :
Menu (hardkey) Function/Parameter Setting
Vertical (sensitivity) 100 mV/div
(channel key}
Horizontal {time/div) 50 ns/div
(Setup) (mode) repetitive
Display (mode) avg
# of avg 8
Press Define meas_, then with the softkeys set statistics to on.
With the soft keys select define, user defined, and measurements.
SS a EOE ——— aE TT
For valid statistical data
In repetitive mode, measurement specifications are valid with eight or more acquisitions
averaged. Statistics accumulated before the required number of averaged acquisitions may show
the instrument to fail the specification. This is particularly true for minimum and maximum in this
case since they are set by measurements taken with the fewest averages.
Ifthe procedure above is followed exactly, the required number of acquisitions are averaged
before statistics are turned on. If however, Clear display is pressed after statistics are turned on,
averaging and statistics are restarted simultaneously and the result is erroneous data collected
from the early averages.
Ifin doubt about the statistical data, after #Avg is complete press Define meas, select meas, )
and turn statistics off then on. This restarts the statistics without restarting averaging and the
resultis valid data.
Initiate a delay measurement.
Press (blue) Aime 1 1
The A Time readings should be 25 ns +601.3 ps; minimum 24.399 ns and maximum
25.601 ns. Record the minimum and maximum readings in the Performance Test
Record.
Change the signal generator frequency to 100 MHz (10 ns period).
Set the time/div to 20 ns/div.
Clear the statistics.
e Press Define meas _, select measure, and turn statistics of f then on.
or
e Press (blue) Clr meas ,thenpress (blue) A 'Time 1 1
The A Time delay readings should be 10 ns +301 ps: minimum 9.699 ns and
maximum 10.301 ns. Record the minimum and maximum readings in the
Performance Test Record.