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Frequency Measurement


#1

What would you folks recommend as a reliable and simple frequency measurement circuit that could interface easily with the EMX/USBizi?

I want to measure the frequency of a 3 phase alternator and translate that to RPM’s. I thought I would use the pulse counter ability decribed in:

http://www.microframeworkprojects.com/index.php?title=Managed_Drivers.

I need to find a good method to deliver the pulses from the 3 phase output of the altenrator. The alternator operates in the 10-15k rpm range so a pretty high freqency.

Thanks -AP


#2

A $0.20 PIC10 maybe? or you are asking software?


#3

Hardware. I should probably take apart a DMM and see what it uses to measure frequency. I simply want to count the peaks of the AC sinusoidal wave.


#4

I found this…

http://www.national.com/ds/LM/LM2907.pdf.

-AP


#5

The easiest way to measure frequency is a frequency -> voltage convertor
http://www.analog.com/en/analog-to-digital-converters/voltage-to-frequency-converters/products/index.html?gclid=COGFtIXwp6YCFcse4QodcAebYg

You can do it with a low pass filter but its a bit crass ( rough )

Cheers Ian