​DOSI Lab Notebook

Problems with Oscillations

28 May 2015: While bringing dDOS fully online in spring 2015, Tim Weber often noticed oscillatory behavior at higher modulation frequencies. Usually this behavior is not hugely deleterious because it is strongest at the highest modulation frequencies, and at those frequencies the signal amplitude (relative to a reference) is strongly attenuated. The effect of which is that those oscillations simply look like noise. However, occasionally we would see spectra like the following:

When we looked at the amplitudes of each channel, we saw that the reference channel (chA) was behaving erratically, and was probably responsible for the spiking in the amplitude modulation plot shown before.