I'm hoping someone may have insight into a problem we're seeing. We seem to get a small, but repeating oscillation in our ToF measurements. It's not perfectly repeatable but does seem to show up a lot. Please see plot below of a sample flowrate measurement taken every second for 3 minutes. Blue is a 10 point moving average of the VFR from the MSP. Purple is the measured flowrate on a calibrated magmeter, also with a 10 point moving average.
It seems to cycle every 15-30 seconds or so.
Has anyone seen this kind of behavior before?