Some good books on underwater sound are those by Robert J. Urick.

Sound propogates great in water and wavelenghts can be on the order of a
centimeter so machining tollerances are in the amateur range.  Underwater
transducers can be expensive or require odd materials, but you can do a lot
with fish-finder transducers.

As for phased arrays... Waves is Waves!  I read microwave and optical
journals, and I do some optical work as well as my usual sonar work.

Also look at the field of Non Destructive Testing (NDT) and Ultrasonic
Testing (UT) as they send sound waves through steel with great precision,
looking for cracks, bad welds, etc.

Doug Butler
Senior Engineer
Sherpa Engineering


> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Peter Meleschko
> Sent: Monday, June 03, 2002 4:00 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [EE]: Phased arrays, ultrasound etc.
>
>
> Hi,
>
> I don't know if I can be of any help but I'm working on a side scan
> sonar (250KHz) myself. I guess that's in the same direction as you?
>
> Peter
>
> man, 2002-06-03 kl. 21:38 skrev Goring, Steve:
> > You could help me out Brandon ...
> >
> > I am developing a small ROV and the next bit involves some
> > underwater sonar ( freq range 40 - 500 khz ).
> >
> > Higher the freq, more direction less range.
> >
> > Does that sound like something that would interest ??
> >
> >
> > Steve
> >
> >
> >
> > -----Original Message-----
> > From: Brandon Fosdick [mailto:bfoz@TERRANDEV.COM]
> > Sent: Monday, June 03, 2002 8:18 PM
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: [EE]: Phased arrays, ultrasound etc.
> >
> >
> > I'm looking for a new project and phased array antennas have always
> > intriqued
> > me. RF is a bit of a black art for me so I'm thinking about playing with
> > sound
> > instead. I have no idea what I'm going to make, this is still in the
> > thinking
> > stage. Maybe a locater beacon/tracker for model rockets.
> >
> > I understand the basics of phased arrays, but I'm not too clear on the
> > details.
> > Both google and amazon have lots of info on RF arrays, how much
> of that is
> > applicable for sound? Since both sound and EM radiation are
> waves I would
> > expect
> > to find a lot of similarities. Some of the RF books on amazon are a bit
> > expensive, and I'd hate to spend a lot of money on a book shelf
> ornament.
> > Any
> > recommendations?
> >
> > I did a quick Digikey search for microphones and everything
> that came up was
> > limited to audible frequencies (<20kHz). Where do I find a good
> source of
> > high
> > frequency microphones/speakers?
> >
> > What frequency range should I be looking at? I have pets so I'd
> like to go
> > high
> > enough to avoid annoying them if possible. Any idea what range medical
> > ultrasound devices use?
> >
> > I imagine I'm going to need some high speed ADC's. I've looked over the
> > corresponding parts from TI and Maxim (any other manufacturers
> I should look
> > at?) and there's a wide variety to choose from. What are ECL interface
> > levels?
> > I've never designed a digital circuit over 20MHz, any gotchas
> that I need to
> > know about?
> >
> > --
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