A computerized automatic measuring system for calibration of underwater sound transducers

This project was conceived to develop the hardware phase of a computerized electronic system that would provide computer-controlled measurements of underwater device parameters in the Anechoic Tank Facility (ATF) of the Naval Research Laboratory's Underwater Sound Reference Division (USRD). This electronic system operates in conjunction with USRD's new PDP-11/45 computer, remotely located in a Computer Center, to control the ATF system by software programming. This system enables an operator to communicate control parameters to the computer in simple English-language statements and to monitor and control the received signal gating during the measurement process. The major advantages realized with use of this computerized electronic system include, real-time analyses of the test transducer to resolve problem areas while the transducer is suspended in the tank under the imposed environmental conditions, recorded accurate and repeatable setup and control conditions for the measurements. Computerized data reduction that provides uniform report formats, and accurate measurements, previously unattainable, of load impedance wherein the voltage or current waveforms powering the test transducer are distorted. This system also has a completely manual mode or, via an integral acoustic coupler, which may communicate over a commercial telephone line with any remote computer. This hardware phase has been implemented in the ATF, and its effectiveness will continue to be analyzed relative to possible use in the other USRD measurement facilities.