Spent the morning trying to shape a PSD so that we could use it to get calculate the rejection ratio of the inertial referencing systemfor the GVT SBIR over the entire band of 1-100Hz. The set up consists of gluing the test accel onto the shaker, and mounting the Keyence laser sensor so that it points at the accel. That way you are measuring the EXACT SAME motion with both sensors. The signals are then differenced in order to calculate the rejection ratio.
Tried using the hydraulic shaker at first, however this shaker causes too much vibration to be reacted back into the work plate, which would cause the laser to shake. This being the case, I switched to an electrodynamics shaker. This proved more suitable and easier to work with.
I tested several different source voltages and bandwidths. As it turned out, I needed to source a relatively high voltage from the VXI source card in order to get enough energy in at low frequencies, but then had to use a lowpass filter to filter out the higher frequencies that were also inevitably high in energy due to the high source voltage.
After this I ordered some LN for Bryce, and talked with Scott P. about synchronizing the last Kaman probe box that was used for World View. He said he would discuss it tomorrow.
Brad talked to me more about the rejection ratio test. The noise floors I had been using as a basis for my previous PSD shapes were not the right ones. You need to use the noise floor of the signals AFTER they have gone through the circuit. He outlined a new approach going forward in an email.
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