The recording system

 

preamp amp

Currently the recording system of cetaceans sounds is a manual system, which is activated ad libitum during navigation when there are sightings of Odontocetes.

The existing system is as follows:

• sensors piezoelectric ceramic-drawn (50 ohm impedance, frequency response 3 Hz, 32 kHz);

• amp;

• laptop;

• digital recorder Sony TDC-D100 DAT;

• audio device Yamaha USB500;

• software provided by IFAW (International Fund for Animal Welfare);

• Software SIA SmaartLive 5;

• Software varied.

The sounds picked up by the hydrophones are amplified by the amplifier (the signal would otherwise be too weak to be heard). Through the Yamaha audio device the sound is sampled at 44100 Hz with 16 bits per sample, and the files are saved on the hard disk so sistemaregistered the notebook.

When the capacity of the hard disk is reached, the recorded sounds are transferred to tapes through the DAT recorder, so that they are available when needed.

 

Functional architecture of the current recording system

All instruments are powered through the energy delivered on board

 

sistema funarch

 

 

 

The logical architecture of this system is divided into the following functional areas:

1. Sound acquisition. The sound functionality acquisition can transform the sound of the marine environment in a series of bits which can then be recorded on a digital medium or analyzed.

2. Recording. Recording is the feature that allows you to store the sounds captured and make it available for future use.

3. Analysis of the data collected. The analysis of the data collected is the feature that analyzes various aspects of the recorded sound and can be made directly during the capture of the sounds or made available at a later time using the data recorded on digital media.

 

 

 

Physical architecture of the current recording system

The mapping between logical and physical architecture can easily derive from the structure of the system.

Looking more in detail:

1. Acquisition of sound. The acquisition of the sound is made through hydrophones connected to the amplifier and the audio device Yamaha USB500, which convert sound into digital samples suitable for recording and analysis.

sistema fisarch

 

2. Recording. Recording is made through a laptop, or, better, through the hard disk of it and the digital recorder Sony TDC-D100 DAT and obviously the tape support attached to it (DAT tape, Digital Audio Tape).

3. Analysis of the collected data. The analysis of the collected data is made of two different moments: when the sound are captured and later with the recorded sounds. Of course the real-time analysis and off-line analysis require different tools. The analysis is carried out online by software tools provided by IFAW and the software of the SIA SmaartLive 5. Obviously, these programs are resident on the notebook. For the analysis made  with the recorded data we’re using the various software listed above (SpectraLab, Cool Edit and MatLab), which may be resident on the laptop or on another computer located elsewhere.