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MOVING AVERAGE FILTER
Moderators: Ajay Bhargav, Arun Kumar V, pdi33, Shailesh NAYAK, ۞ TPS ۞, shyam, sashijoseph, ExperimenterUK, DavesGarage
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indigo_rei
Fri May 29 2009, 08:42AM
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Hi guys, I really need a reference from book or web to coding Moving Average Filter in 89s51 . I tried to find many other places. Please send me the file or the download link. thank you very much.

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DavesGarage
Fri May 29 2009, 01:50PM

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In situations like this, Google can be your friend.

If you type "moving average filter" into Google, you will find many references to this technique.

Here are a couple for you to investigate and read:

http://en.wikipedia.org/wiki/Finite_impulse_response
http://en.wikipedia.org/wiki/Filter_(signal_processing)
http://en.wikipedia.org/wiki/Signal_processing

I hope this helps you,

-Dave
"Basic research is what I am doing when I don't know what I am doing"
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indigo_rei
Sat May 30 2009, 07:14PM
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thanks for your help dave, but wikipedia just a theory. I need a real implementation on 89S51. Could someone help me ?
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Ajay Bhargav
Tue Jun 02 2009, 07:47AM
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I believe 8051 is small for complex calculations, its better to go for faster MCUs or a DSP.
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DavesGarage
Tue Jun 02 2009, 12:53PM

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There are many different "types" of filters you can write, and the boxcar (or moving average, as you called it) or rectangular filter is only just one of 'em.

Here is a comparison of a variety of filters, and the kind of effect they can have on your data, as a function of frequency...




to make a simple "moving average" filter, you merely need to add up the data, then divide by the number of data elements.

If you add all the elements every time you calculate the average, it will cost you n additions plus one division.

On the other hand, if you keep track of where the oldest data is located, then as the data progresses, you merely add the new data, subtract the oldest data, and do the division again...

This method only costs you a single addition, a single subtraction, and a division. Much faster...

I won't write the code for you. I hope this helps, though...

-Dave
"Basic research is what I am doing when I don't know what I am doing"
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