The following report presents a study of body-area, free-space ultrasonic communication system. Two analog communication systems are investigated. The initial communications system setup relies upon the amplitude modulation (AM) techniques to transmit the signal. Such a system is prone to noise since the amplitude of the signal is directly affected by distance and the signal strength will deteriorate. The secondary communication system involves utilizing frequency modulation (FM). This method avoids the issue of losing information due to amplitude deterioration, but encounters delay issues. The main hardware components used in the approach outlined include ultrasonic transducers (UTs) used for both transmitting (Tx) and receiving (Rx), modulation and demodulation stages, several filters, an audio microphone and amplifier, and a speaker. The range of interest is 1-2 meters compared to radio frequency (RF) communication ranges of kilometers. For medical use, this range need not exceed a human’s body length
