I have a question regarding white noise generated by an arbitrary waveform generator (AWG). I'm working with one (AWG5014C) that has a sampling rate of 1.2 GSamples, with which I want to produce white noise that is relatively flat over some range, for example up to 300 MHz.
Here I show the PSD as measured with a spectrum analyzer; a clear dropoff is visible starting at relatively low frequencies compared to the sampling rate (or maybe not?) and I am wondering what the cause of this is.
I should note that I am not so much looking for a 'fix' for this; I assume that this is just a consequence of how the machine operates. My question is of what it is a consequence, so that I can understand it better. One clue that I have is that I can for example use the spectrum analyzer to extract a filter that will offset the dropoff; treating the AWG as some sort of black box that applies a filter |H(omega)| to my time series, applying |H(omega)| gives me a flat spectrum.
As a short aside, you can ignore the first points that are way off. Although I don't understand where they come from (another question?), they seem to be artifacts of the spectrum analyzer.