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FYI...Digital signal Processing in sonars.

Old 10-08-2014, 10:04 PM
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Default FYI...Digital signal Processing in sonars.

Here is an article than some may find interesting.
.......................

Digital Signal Processing (DSP)



DSP can greatly simplify the operation of equipment by reducing, or even eliminating, the need for manual adjustment of controls by automatically providing optimum results. You can see the benefit of DSP most clearly in devices that produce an image.

DSP-equipped fishfinders, for example, can deliver exceptionally clear images of all that lies below the boat, differentiating between fish targets, fish and sea surface turbulence, and fish and the bottom.

In a conventional fishfinder design, the performance of the sonar transmitter and the receiver is determined by the unchanging electrical characteristics of the various resistors, capacitors, inductors and transistors used in the circuit.

DSP works by substituting a software controlled, special-purpose microprocessor, the DSP chip, for a collection of conventional electronic components in signal processing circuits. The processing of data is determined by software, not hardware. A multitude of operating choices are available and can be changed instantaneously to optimize the final result.

Specific attributes of DSP technology can be clearly seen in the Furuno DFF1 black-box fishfinder. In a conventional unit, the rate at which successive pulses of sonar energy (pings) are transmitted, the length of each pulse and the power used is adjusted by front panel controls. In the DFF1, all of these variables are controlled by the unit’s software, managed by the DSP chip. The system evaluates the result of the chosen settings and automatically makes changes to improve the outcome — clear visibility of fish with minimum interference from both surface and bottom reflections.

In the DFF1, an echo received by the sonar transducer is converted into a series of 36-bit digital words and processed at rates as high as 56 Mhz. Operation at these speeds allows the system to optimize each one of the transmitted pulses of sonar energy and to make thousands of adjustments to the receiving circuit as each successive sonar reflection reaches the transducer. Depending on the system, more than 200 separate adjustments may occur in a fraction of a second.

While a conventional fishfinder in the hands of a skilled operator can perform as well, the average user will find that the automation provided by DSP produces Superior results.


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Last edited by semperfifishing; 10-17-2018 at 12:12 PM.
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Old 11-20-2014, 12:22 PM
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So what fish finders currently incorporate dsp and which are still analog?
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Old 11-20-2014, 05:36 PM
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Originally Posted by Hossharris View Post
So what fish finders currently incorporate dsp and which are still analog?
DSP really got underway about 7 to 8 years ago with units like the Furuno FCV 585 ,FCV 620..Lowrance HDS1, Simrad NSS and NSO series.

Furuno units like the FCV600L were of the analog design.

DSP design was widely first used in cell phones...they used analog and DSP technology hand in hand.
And then to personal audio etc.
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Old 10-17-2018, 11:39 AM
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