A hardware system for the field test unit was designed and implemented using off-the-shelf components for digital electronics and for all of the amplifiers and transducers. The software package developed allows easy access to all functions supported by the hardware in a flexible and extendable, multilayered menu-driven package. A radix four Fast Fourier Transform algorithm was chosen and implemented in software to transform the time domain data into the frequency domain. Development of a Time Delay Spectrometry system was begun to eliminate the need for a long wait after the transmission of sound before receiving. Investigations into pattern-recognition techniques involving imprecise forms of data and data partitioning have begun, as has research into phased array polaroid transducers. Materials testing was begun to investigate various types of material as to the ability of these materials to stop sound from penetrating and thus hampering the detection of concealed handguns. The study recommends that the Phase III effort be continued to completion of a useful field test unit, and suggestions are offered for achieving this. 12-item bibliography and appended data.