I was expecting a nice smooth curve, and this is what I got. Bigger...

I filtered the results and grabbed just the data from the A channel. Things still weren't looking that good. Bigger...

So I filtered the results and grabbed just the data from the B channel. This looks much better. It appears that the A channel isn't quite 90 degrees out of phase and that the high and low portion of the pulse aren't quite equal width. Bigger...