Agilent Technologies E3646A, User Manual, Page: 186 / 211

Appendix Service Information
Constant Voltage (CV) Verifications
186
CV PARD (Ripple and Noise)
Periodic and random deviations (PARD) in the output (ripple and noise) combine to
produce a residual ac voltage superimposed on the dc output voltage. CV PARD is
specified as the rms or peak-to-peak output voltage in the frequency range from 20
Hz to 20 MHz.
• VRMS measurement techniques:
When measuring Vrms ripple and noise, the monitoring device should be plugged into
the front of the terminals at (A) in Figure A-2. Use the BNC (Female) receptacle and
the cable (BNC to BNC) to connect the monitor device to the power supply. To reduce
the measurement error caused by common mode noise, it is recommended to twist
the connection wire between the BNC receptacle and the output terminals. The load
resistor is connected to the terminal at (B) in Figure A-2. Twisted leads between the
load resistor and the power supply helps reduce noise pickup for these measurements.
N o t e : For better measurement result, it is recommended to make the connection between
the BNC receptacle and the output terminals shorter as much as possible, and to use
the recommended split ferrites with the cable (BNC to BNC) as shown above.
BNC Cable
Load Resistor
Input
RMS voltmeter
RMS voltmeter
(Front Panel Connections)
(Rear Panel Connections)
BNC
Receptacle
Split Ferrites*
Input
Load Resistor