sayaf,
Thanks for including the image -- it's a big help. Now I'm not the greatest expert at filtering, but to my eye you're getting a pretty reasonable approximation. I don't know how much better you can get when you only have about 8 PWM cycles for defining a half-cycle of the sine wave you want to see. At least, it looks pretty good if you have to handle a very general case of modulation.
Can the modulation always be considered a pure sine wave with a constant frequency throughout your sampling time? If so, then you can use that knowledge to your advantage -- for example, pass a few cycles of your filtered signal into one of the tone-extraction vi's that ship with LabVIEW. I'm sure there are other good (probably better) methods as well.
-Kevin P.
ALERT! LabVIEW's subscription-only policy came to an end (finally!). Unfortunately, pricing favors the captured and committed over new adopters -- so tread carefully.
