Yes I agree that there are points in the plot where dv/dt = 0. This is not what is wanted or intented - but then I think the reason for that are as follows :

1. Use of an 8 bit DAC to generate the Sine plot. I am currently generating 180 points for 0-180 degrees. Thus the resolution is not big. ( I think I should generate the 0-90 plot using all 256 bits to further smoothen out and then manipulate this same data for the next three quadrants )

2. No low pass filtering either in software or hardware used.

What you see is the raw plot on first run, just to make sure the algrothims and hardware.

And my final target is a plot of Feedback Vs Command. That is now under generation and it is as smooth as a tennis court, even with no filtering. Will post it today.

Thanks.

Raghu