Re: Precision Phase angle measurement


"psdayama" <psdayama@xxxxxxxxx> wrote in message
news:1164731111.822736.279550@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Thanks for message. I am measuring our power frequency that is 50Hz
+/- 2.5Hz.
It may be that I will need to measure at 60Hz.

50Hz is 20mS
If one cycle is 360 degrees = 20mS then 5 mins is around 4.6uS
5uS is around 10 ticks of a 2MHz clock so that should be ok.

So the problem is probably with the zero crossing detector.
See the post by DaveM and use a faster comparator.

If you still have a problem check that any voltage hysterisis in the
comparator isn't giving an error. This size of this error would depend on
the source voltage, noise and the comparator thresholds.




.

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