Agilent Technologies N6751A User Manual page 134

Appendix B Verification and Calibration
134
3
Set the differential amplifier to multiply by ten, divide by one,
and 1 Megohm input resistance. The positive and negative inputs
of the differential amplifier should be set to AC coupling. Set the
oscilloscope's time base to 5 ms/div, and the vertical scale to 10
mV/div. Turn the bandwidth limit on (usually 20 or 30 MHz), and
set the sampling mode to peak detect.
4
Program the power supply to the settings indicated in the in the
test record form for the appropriate model under "CV Ripple and
Noise" and enable the output. Let the oscilloscope run for a few
seconds to generate enough measurement points. On the Agilent
Infiniium scope, the maximum peak-to-peak voltage
measurement is indicated at the bottom of the screen on the right
side. Divide this value by 10 to get the CV peak-to-peak noise
measurement. The result should not exceed the peak-to-peak
limits in the test record form for the appropriate model under
"CV Ripple and Noise, peak-to-peak".
(If the measurement contains any question marks, clear the
measurement and try again. This means that some of the data
received by the scope was questionable.)
5
Disconnect the oscilloscope and connect an rms voltmeter in its
place. Do not disconnect the 50 ohm termination. Divide the
reading of the rms voltmeter by 10. The result should not exceed
the rms limits in the test record form for the appropriate model
under "CV Ripple and Noise, rms".
Transient Recovery Time
Test category = performance
This test measures the time for the output voltage to recover to
within the specified value following a 50% change in the load current.
1
Turn off the power system and connect the output as in Test
Setup figure (A) with the oscilloscope across the sense terminals.
2
Turn on the power system and program the program the
instrument settings as described in the test record form under
"Transient Response".
3
Set the electronic load to operate in constant current mode.
Program its load current to the lower current value indicated in
the test record form under "Transient Response".
4
Set the electronic load's transient generator frequency to 100 Hz
and its duty cycle to 50%.
5
Program the load's transient current level to the higher current
value indicated in the test record form under "Transient
Response", and turn the transient generator on.
6
Adjust the oscilloscope for a waveform similar to that shown in
the following figure.
7
The output voltage should return to within the specified voltage
at the specified time following the 50% load change. Check both
loading and unloading transients by triggering on the positive
and negative slope. Record the voltage at time "t" in the
performance test record form under "Transient Response".
Series N6700 User's Guide