BIAS Buoy Program are described. Diagrams of the complete measurement systems are 

 shown in DTNSRDC Drawings C-398 and CA32. 



BUOY EVALUATION MEASUREMENT SYSTEM 



The measurement system used for BIAS buoy evaluation is divided into four sections 

 to simpUfy discussion. These are buoy instrumentation, towcable, shipboard sensors, and 

 data center instrumentation. 



Buoy Instrumentation 



The buoy instrumentation consists of three units located within the buoy housing. One 

 unit is an instrumentation package consisting of the buoy pitch and deep-depth sensors, the 

 remotely-controlled calibration networks, a four-channel FM telemetry transmitter, a d-c 

 voltage regulator, and two leak detector networks. This package is placed in a space in the 

 stern of the buoy normally used to hold the buoy depth instrument housing. The second 

 unit, the stabilizer-angle sensor, is located in the center vertical fin of the buoy and, finally, 

 the shallow-depth gage with associated blanking valve is located in the buoy near the tow- 

 point. The buoy evaluation instrument housing with interconnecting cables to the shallow 

 depth sensor with blanking valve and to the stabilizer servo-motor assembly is shown in 

 Figure 7. 



The calibration network consists of a printed circuit board including a relaxation 

 oscillator, sillicone-controlled rectifier, and a 500-micro-farad condenser, and a rotary- 

 solenoid Ledex switch Model S-1009-041, Size 2E. A circuit diagram of the calibration net- 

 work is included in DTNSRDC Drawing C432-2. 



The four -channel FM telemetry subsystem is made up of four voltage-controlled 

 oscillators (VCO's) and a mixer-amplifier output unit. The VCO's are lED, Division of 

 Conic Corporation, Model CSO-235A, and the mixer-amplifier is lED Model CMA-435A. 



The d-c voltage-shunt regulator (Super-reg Model 75T27) supplies 28 volts d-c to all the 

 electronic circuitry in the buoy. Input power to the regulator is supplied via the towcable 

 from a regulated current supply of 135 milliamps located in the data center. 



The leak detector consists of a strip of brass positioned near the inside bottom of the 

 instrument housing and is electrically insulated from the housing which is at ground potential. 

 A drop of water in the housing will partially short the strip to ground, which will cause a 

 relaxation oscillator to emit a sawtooth oscillation. Oscillation-signal peaks are detected in 

 the recorded pitch readout and serves as a leak warning signal. 



A second leak detector is located in the servo motor cavity of the buoy center vertical 

 fin. A leak signal in this area is detected in the recorded deep-depth readout channel. 



15 



