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From: Rick Lyons on 7 May 2008 06:49
On Tue, 6 May 2008 16:00:56 -0700 (PDT), keithmarsh
<keithmarsh2(a)gmail.com> wrote:

>Hello everyone.
>
>I'm completely new to DSP, coming from a background of PIC18.
>
>I have two mics that I want to use for sound direction detection, and
>I guess using fourier transforms to get the freqs out from one
>channel then looking for a rough match in the second channel over time
>(and vice-versa) is the correct way to go.
>
>I have no experience of dsPICs and I'm looking for
>1. some pointers about learning the maths involved
>2. some pointers about using dsPICs to get the job done painlessly
>3. is there some IC commercially available that'll do this job.
>4. am a barking up the correct tree
>
>I've glanced over the comp.dsp faq list, but I think it may all be a
>bit too advanced for me. Not really up to A-level maths or above.
>I'm looking for some application examples that'll show me the ropes
>without pain.
>
>Any advice / references / links / FAQs gratefully received.

Hi Keith,
To echo what Jason (cincydsp) said, you've picked
an "awfully high signal processing mountain
to climb."

Google on "direction finding". You'll get thousands
of hits. Review some of the tutorial material
on the web and you'll start to develop a feeling
for what's involved in "direction finding".
The material on the web will mostly describe
radio frequency (RF) direction finding, but the
basic ideas, the basic principles, you encounter
on the web will also apply to audio direction finding.

I know almost nothing about direction finding, but
I do know that it's NOT a simple problem.

Good Luck,
[-Rick-]

From: Ron N. on 7 May 2008 09:32
On May 7, 3:43 am, Rune Allnor <all...(a)tele.ntnu.no> wrote:
> > 1. some pointers about learning the maths involved
>
> The maths required includes
>
> - Complex numbers
> - Fourier transforms
> - Z transforms
>
> and while not an absolute must, knowledge in linear
> algebra will significantly ease your pains with the
> engineering.

For limited purposes, it's possible to formulate the Fourier
transform without complex numbers, just a lot of trigonometry
and calculus (although complex algebra does make it possible
to simplify and generalize the results).

For a general introduction to direction finding at the
popular science level, I recommend the book:
"Blip, Ping, and Buzz: Making Sense of Radar and Sonar"
by Mark Denny
Johns Hopkins University Press 2007



IMHO. YMMV.
--
rhn A.T nicholson d.0.t C-o-M
From: Jerry Avins on 7 May 2008 13:15
kronecker(a)yahoo.co.uk wrote:

...

> You sound like an amateur. Go study Elect Engineering first and come
> back in 4 years. I often want to do brain surgery but they won't let
> me.

What a meat-handed, narrow-minded thing to say! Isaac Newton was an
amateur too.

Jerry
--
Engineering is the art of making what you want from things you can get.
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