This blog post is a continuation of the project I worked on for my Analog Discovery 2 RoadTest Review. Check back soon for updates!
UPDATE 1 (7/16/19)
I've managed to get the analyzer partially functioning. I'm getting reasonable magnitude response estimates now, but the phase coming out of the FFT VIs is all zeros. That's wrong (the phase of the FFT of a first-order Butterworth filter should have a -90° shift starting from zero centered about the -3dB corner frequency of the filter on a log plot), and it's messing up my phase estimates (obviously), and also the SNR estimate. I'm not completely happy with the magnitude estimates either; the smoothing filter eliminates some of the noise issue, but because it is linear and the display is logarithmic, it does too much at low frequencies and not enough at high frequencies.
At this point, it seems like the obvious next step is to figure out why the imaginary part of the FFT is missing. I'd also like to figure out a better, less noisy way to display the magnitude estimates.