Agilent Technologies E3634A, E3633A manual CV PARD Ripple and Noise

Chapter 3 Calibration Procedures

Constant Voltage (CV) Verifications

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 (B) in Figure 3-2. Use the coaxial cable and BNC female to banana plug adapter to connect the monitor device to the power supply. To reduce the measurement error caused by common mode noise, it is recommended that you use a common mode choke between the cable and the BNC adapter. The common mode choke is constructed by inserting coaxial cable into Ferrite Toroidal core. The load resistor should be connected to the terminal at (A) in Figure 3-2. Twisted leads between the load resistor and the power supply helps reduce noise pickup for these measurements.

1Turn off the power supply and connect the output to be tested as shown in Figure 3-1 to an oscilloscope (ac coupled) between (+) and (-) terminals. Set the oscilloscope to AC mode and bandwidth limit to 20 MHz. Connect a resistive load (2.0 W)* or (12.5 W)** to the terminal at (A) in Figure 3-2.

2Turn on the power supply. Select the 20V/10A* or 50V/4A** range, enable the output, and set the display to the limit mode. When the display is in the limit mode, program the current to the full rated value (10.0 A)* or (4.0 A)** and the voltage to the full rated value (20.0 V)* or (50.0 V)**.

3Check that the front panel CV annunciator remains lit. If not lit, adjust the load down slightly.

4Note that the waveform on the oscilloscope does not exceed the peak-to-peak limit of 3 mV.

5Disconnect the oscilloscope and connect the ac rms voltmeter in its place according to the VRMS measurement techniques above. The rms voltage reading does not exceed the rms limit of 0.35 mV* or 0.5 mV**.

*For Agilent E3633A Model **For Agilent E3634A Model

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