SeaModem
Low Cost Under Water Acoustics Modem for Shallow Water Communications
SeaModem was designed to offer a suitable open hardware/software platform for developing underwater cost-effective control, communication and localization applications, especially in their first concepts validation phases. In order to expand as much as possible its flexibility, Seamodem consists of two main boards in its basic configuration the Power board and the DSP board.
The Power board is outfitted with a single channel power amplifier that drive the ceramic transducer and with a single receiver channel that includes a low-noise preamplifier, a band pass filter and an automatic gain control (AGC) circuit. This board can be easily reconfigured to operate in different frequency ranges by simply substituting few components and the ceramic transducer.
The DSP board is equipped by an ultra low-power fixed-point digital signal processor and with a two-channel audio codec that can sample the signals up to 192 KHz. All parameters are fully reconfigurable and can be adapted to any need with easiness, also remotely.
| Frequency band | 25-35 KHz |
| Selectable FSK modulation tones | 2 - 4 - 8 tones ( 750 - 1500 - 2250 bits/sec ) |
| Error detection and correction | 16 bits CRC and Viterbi algorithm implementation |
| Transmission power | up to 40 W |
| Host interface | UART |
| Range capabilities | distance calculation between two modems via one-way or two-way protocols up to 400 m in shallow water environment |
| Network capabilities |
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| Expansion header | BeagleBone/BeagleBoneBlack compatible |
| JANUS enabled | JANUS signaling method runnable on SeaModem & BeagleBone configuration |
| Power supply | 12VDC or 24 VDC (with external DC/DC Adapter) |
| Weight | Board 150 g, Transducer 380 g |
| Dimensions (LxWxH) | 130x60x25 mm |