Transducer Array System Design for Underwater Communication Systems Using Audio Frequency

Indonesia, as the largest archipelagic state in the world, has wealth of land and water territory lie from Sabang to Merauke. One of the best communication systems that works in water territory is one that utilizes acoustic devices with low frequency as they have better resistance to water attenuation. This underwater communication system is designed to be utilized for the needs of Indonesian territory defense and security from intruders who try to enter their sovereign region and may be used to meet the welfare needs of people who spend activities carried out at sea. The purpose of this research is to create an underwater communication system that transmit signals that works in frequency range of 40-43 kHz using microcontroller, analyzing the transducer installation in an array on the transmitter and receiver to reduce the bit error rate (BER), as well as adding additional system channel coding as encoding technique for the information bit according to the channel characteristic to reduce errors in data transmission. In this research, a transducer array system design test has been carried out at a baud rate of 1200, 2400 and 4800 for data transmission of 7, 14, 21, 28 and 35 bits. Modem designed to support this communication system works at a frequency of 40-43kHz. It is proven that the installation of transducers in an array can improve the quality of the data received as array as it compensates each demodulator BER. Also. CRC (cyclic redundancy check) as channel coding has successfully implemented in this prototype. This paper only covers transducers array implementation.