High-Speed High-Frequency Acoustic Modem for Image Transmission in Very Shallow Waters

A one-way, high-speed, high-frequency acoustic modem (HS-HFAM) operating between 260 kHz and 380 kHz has been developed to transmit compressed underwater images and status information in real-time. High data rates are made possible using a high-resolution decision feedback equalizer with parallel algorithm for tracking and compensating large Doppler. Experimental results show that this modem achieves 13298.2 information bits per Joule at 87768 information bits per second and at a range of 88 m in ports and shallow waters.