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Unable to get Zero Phase shift after filtering PWM

Hi,
After filtering the PWM signal i'm not getting the exact shape of Sine wave, i'm using the Zerophaseshiftfilter.vi in the blockdiagram.I've also attached the resulting waveforms that i'm getting. Anybody help me out.
Thanks
sayaf
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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.
CAUTION! New LabVIEW adopters -- it's too late for me, but you *can* save yourself. The new subscription policy for LabVIEW puts NI's hand in your wallet for the rest of your working life. Are you sure you're *that* dedicated to LabVIEW? (Summary of my reasons in this post, part of a voluminous thread of mostly complaints starting here).
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