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Technical article on sonar technology

Old 11-23-2017, 07:23 AM
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Default Technical article on sonar technology

If you are interested in the technical aspects of fish finder sonar technology, I found an article with loads of info.

sonar_explained.pdf

The article has lots of simple math, but it is well done. It has good explanations of transducer function, standard, CHIRP and side scan sonar.

There will not be a quiz later!

Last edited by m9000; 11-23-2017 at 11:34 AM. Reason: typo
Old 11-23-2017, 09:28 AM
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Default Informative and Worthwhile

Thanks, very useful.
Old 11-23-2017, 09:58 AM
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outstanding. I might argue this one, however:

"Wattage
Your depth finder puts out a constant amount of power. "


Pulse length has traditionaly been adjustable, at least on non CHIRP systems. That affects directly power to the target. And, many sounders do adjust power as a function of the depth range they are on. Again, not sure what CHIRP sounders do here.

while I'm thinking about Watts and power, and this paper.

RMS Power is not a proper mathmatical representation of power. You can do root-mean-square of Volts and Amps, but not power. If engine manufacturers played this same game with cars, they would be called out on it. A 600W depthfinder can deliver this 600Watts for a few milliseconds. If you bought a 300 HP car, and found out that the engine could only deliver that power for a fraction of a second, you would be dissapointed.

Sonar shares this power issue with radar systems. There, it is acceptable to indicate peak transmit power. So, you have a 12kW radar that can put out that amount of power for a very short amount of time. Radars don't, or shouldn't, be specing "rms power".

So, sonar guys: It's peak power with an associated pulse length. RMS power is unmeasurable and nonsensical.

Last edited by diver dave; 11-23-2017 at 12:12 PM.

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