Well, I believe it does match the performance for this particular application. Let me explain why I think so and perhaps the experts will correct me if I'm wrong;I'll nitpick that one because it doesn't "match the performance" it matches the freq but has 20% less vertical resolution. In signal generation that can be significant although I agree it's less ciritcal in this case and for a budget sine signal generator app you came close to matching the performance.
Here's a plot (below) of duty cycle to output voltage for a pair of 256 element sine arrays, one with 80 duty cycle steps and the other with 100 duty cycle steps. It's an overlay plot and if you look very closely you can just see some blue spots from the 80 level plot peeking through from underneath the red 100 level plot. I did not make any attempt to fine tune either array or account for rounding errors. Even so, the plots are nearly identical.
I believe that 64 duty cycle levels would produce a very nice wave form in this particular application and that using 80 levels is overkill. If 80 duty cycle levels is overkill, 100 levels is merely more overkill and will not contribute to performance in a significant way. In this case you could claim that 80 levels is less overkill compared to 100 levels, but I don't think you can claim that 100 levels will have significantly better performance.
I'd love to hear what the experts think and if they would characterize the 80 level wave form pictured below to be deficient in any way.
Kind regards, Mike
10.8 KB Views: 50