I have a power source that is supposed to be low noise, and i want to verify that the data the company sent me is indeed accurate. In order to do this, i want to reproduce their graph showing current noise density (nA/root(Hz)) on the Y axis, and Hz on the X axis. I am an undergraduate physics student, and i am not familiar with making these types of measurements.(adsbygoogle = window.adsbygoogle || []).push({});

The method i have been using is connecting the source up to a dummy load (provided by the company for testing), to a pre-amp, to a oscilloscope. I took data off the oscilloscope but had issues in trying to understand how to get the correct values on the axis. An FFT seems needed, btu i am using igor for data processing and It only requires one set of data for an FFT and doesnt seem to require a time axis which perplexs me. It also doesnt help that i have not studied the math behind FFT's quite yet.

Does anyone have any suggestions? I have access to a Spec. Analyzer if thats useful, but it goes from 9KHz to 29.5Ghz, and the graph id like to reproduce goes from 0 to 10^5Hz.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Measuring Current Noise Density

**Physics Forums | Science Articles, Homework Help, Discussion**