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Ripple and noise characteristics

for lab devices, MME, MMS, VME and NIM

All multichannel modules are optimized for a low ripple of the output voltage. The output ripple consists of three components with different frequencies:

The fundamental oscillation of the converter, which is in the region of 40 to 120 kHz. The filters in all modules are designed to keep this component below 5 mV at full-load, in most module types even below 1-2 mV. Since this component depends on the load it decreases significantly if the load is reduced.

Noise caused by non-ideal electronic parts (finite time constants, finite amplification, ground noise) in the control circuit. The frequency of this noise component is in the range of 10 Hz up to a few kHz. Typically this component is below 10 mV, for Standard and High Precision modules with a maximum output voltage up to 4 kV it is below 3 mV. This is achieved by using a dual circuit control for the output voltage, which also guarantees a very good stability of the output voltage under all load conditions.

The frequency interval from 10 to 0.01 Hz is typically not very relevant for spectroscopic applications. In this range a ground noise of analoge parts of the reference voltage generation and control circuits, typically of the order of nanoor microvolts, can result in a noise of some 10 millivolts in the output voltage due to the large amplification factor (> 1000). In case these low frequency noise components may interfere with an application, e.g. for electron-optical implementations, low-noise high precision modules should be employed, which keep this noise component below 5 mV.

Below those frequency ranges a change of temperature can lead to a drift of the output voltage. The operation mode „DAC fineadjustment“ allows to supress this drift to a greatest possible extend.

Ripple and noise classification

LOW NOISE VP-P < 5 mV [f > 1 kHz] | VP-P typ. < 20 mV / VP-P max. 30 mV [1 kHz > f > 10 Hz]
VERY LOW NOISE VP-P < 1 mV [f > 1 kHz] | VP-P typ. < 3 mV / VP-P max. 5 mV [1 kHz > f > 10 Hz]
ULTRA LOW NOISE VP-P < 1 mV [f > 1 kHz] | VP-P typ. < 3 mV / VP-P max. 5 mV [1 kHz > f > 0.1 Hz]
10 μs / DIV
R1 EHS 8060: 6000 V/1 mA | VP-P = 1.4 mV
R2 EHS 8060: 6000 V/0.1 mA | VP-P = 0.4 mV
R3 Ground noise of the oscilloscope 0.8 mV
100 ms / DIV
EHS 8060: 6000 V/1 mA | VP-P = 11 mV
50 s / DIV
EHS 8220p | Vout = 500 V | VP-P = 4 mV