Keysight E3631A, Service Manual

Page: 63 / 131

Calibration Procedures 3
Keysight E3631A Service Guide 61
7 Repeat steps (1) through (6) for the remaining outputs.
Normal mode voltage noise (CV ripple and noise)
The normal mode voltage noise is in the form of ripple related to the line
frequency plus some random noise. The normal mode voltage noise is specified as
the RMS or peak-to-peak output voltage in a frequency range from 20 Hz to 20
MHz.
1 Turn off the power supply and connect the output to be tested as shown in
Figure 3-3 to an oscilloscope (ac coupled) between (+) and (-) terminals.
2 Turn on the oscilloscope. Configure the oscilloscope as shown below:
– Set the oscilloscope to AC mode and bandwidth limit to 20 MHz.
– Set the vertical sensitivity to 3 mV/div.
– Set the horizontal sweep speed to 10 ms/div.
– Enable auto/continuous triggering.
– Enable Vpp measurement function.
3 Connect a resistive load (1.2 ? for +6 V supply and 25 ? for ±25 V supplies) as
shown in Figure 3-3 (see Table 3-2 ).
4 Turn on the power supply and select the output to be tested using the meter
and adjust selection key on the front panel. Enable the outputs and set the
display to the limit mode. When the display is in the limit mode, program the
current of the selected output to the maximum programmable value and the
voltage to the full-scale value (see Table 3-2 ).
5 Check that the front panel CV annunciator remains lit. If not lit, adjust the load
down slightly.
6 Note that the waveform on the oscilloscope does not exceed the peak-to-peak
limit of 2 mV for each of the three outputs.
Output Difference
+6V Output 2.6 mV
+25V Output 4.5 mV
-25V Output 4.5 mV