Hi Imre, Harold,

This methode is much easy with analogic op amp.
Log - sum or diference (with integration) - antilog
There are expensive specialised IC which are doing this.
Of course, can be done with cheap op amp and a termostabilised transistors
array. Depends how large is the bandwith.
But definitely in a large memory PIC may fit the whole thing.

top 10 wishes,
Vasile
http://surducan.netfirms.com


On Tue, 16 Sep 2003, dr. Imre Bartfai wrote:

> Hi,
>
> it is actually the so called "geometric average", which is a product of
> all members, then its n-th root, where n is the number of members. It is
> an interessant question, whether logarithming consumes more time for PIC
> or multiplying (in both case floating-point arithmetic assumed).
>
> Regards,
> Imre
>
> On Thu, 11 Sep 2003, Harold Hallikainen wrote:
>
> > There are ways of decreasing the effect of widely variable data, but you then don't have the mean. I'm trying to remember the method we used in AM broadcast field strength readings to smooth the readings. OK, I just found it. It's the logarithmic average: "The logarithmic average
> > for each radial is the antilogarithm of the mean of the logarithms of
> > the ratios of field strength (new to old) for each measurement location
> > along a given radial." So, to get the log average, you take the log of each reading, average them, then take the antilog.  This is from http://kauko.hallikainen.org/FCC/FccRules/2002/73/154/
> >
> > Harold
> >
> >
> > FCC Rules Online at http://www.hallikainen.com
> >
> >
> >
> > -- John Pearson <xero@CMC.NET> wrote:
> >
> >
> > Is there a simple routine for finding a mean average?
> >
> > I am currently getting just an average by simply adding numbers to one variable, and then dividing it by the number of numbers added to the variable.
> >
> > But is there a simple way to eliminate the numbers that are not as common as the majority.
> >
> > Thanks
> >
> > John
> >
> > --
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> >
> > ________________________________________________________________
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> >
>
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>

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