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Locating an aircraft signal pinger in ocean water can be a daunting task. The ocean has many sounds over a broad spectrum making for a difficult environment to be searching in. The motion and flow of the water adds "noise", or ambient sounds to that emitted by the motions of the sea creatures, as well as those sounds that are used for communication within each species.

To demonstrate techniques that can be used to identify the faint sounds of the pinger in this very noisy environment I have prepared a simulation of a received signal, of a pinger sound (in this case I used 1,000Hz) in random noise.

The original simulated pinger sound is a clean 1 kHz (1,000 cycles per second) sound.


Plot 1 shows a received signal in the presence of noise. It is essentially buried in the ocean sounds.

PLOT 1 - Simulated Pinger Sound Imbedded in Ocean Noise


After some enhancement with a judicious choice of forensic enhancement tools, we have:

PLOT 2 - Simulated Pinger Sound in Ocean Noise After Initial Filtering


Note the discrete one- second repetition rate that is recognized as a possible pinger signal


After additional enhancement we have:

PLOT 3 - Simulated Pinger Sound in Ocean Noise After Additional Filtering


We now have a recognizable waveform that can be evaluated in detail.

Various techniques can be utilized to take advantage of the known characteristics of the pinger output, as compared with the relatively random ocean ambient noise.

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I can be reached at (201) 664-8333 or by email at and on Twitter @ProAudioLabs

Paul Ginsberg, President

Professional Audio Laboratories, Inc.

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