USA As Represented by Secretary of the Navy

Thomas E Stixrud

Barbara J Sotirin

Donald Murdock

An uncomplicated and reliable temperature sensor has a pair thermistors coupled in parallel with a current source that is connected in series with a load resistor. Temperature variations cause a robust current output change that generates a corresponding robust output voltage determined by a proper selection of the load resistor. Increased sensitivity is provided by the robust current to avoid many of the problems otherwise associated with D.C. amplifiers (e.g., drift).

Thermistor controlled current source versatile temperature sensor

This invention is an apparatus and method created around a specialized micomputer attachable to and addressable to each thermister in an array of thermisters used to measure temperature in the sea. The invention provides a number of options so that the same model of microcomputer can be adapted to several different modes of operation and used to monitor a variety of other sensors that have electrical resistance, voltage or current as outputs. Alternate modes of operation for resistive sensors are presented where a number that fixes the measurement as a fraction of the dynamic range of the variable being measured is determined. The system includes the circuits and memory needed to adapt it to any of a variety of sensors measuring physical quantities. The microcomputer contains a counter that can be incremented at several rates, a voltage comparator which can be used to interrupt the counter at a number that represents the measurement, input/output buffers for connections with a remote master control unit whereby command instructions and data can be relayed to and from the microcomputer, and a voltage reference source.

Universal microcomputer for individual sensors

An apparatus hydromechanically decouples a hydrophone arrangement disposed n a water medium from the effects of current, wind and surface wave action. A first float carrying a transmitter-antenna assembly extends through the water-air interface and is tethered to an auxiliary float which buoyantly supports the hydrophone arrangement. A line, hundreds or thousands of feet long, is suspended by the auxiliary float and terminates in a sonobuoy tube at a predetermined depth. From the tube the hydrophone arrangement and a high pressure float are pulled out by a weighted nose portion. After the hydrophone arrangement, high pressure float and a length of line are pulled from the tube, a weak link between the hydrophone arrangement and nose portion snaps allowing the weighted nose to sink. The high pressure float has sufficient buoyancy to support the hydrophone arrangement and a portion of the length of line causing it to assume a cantenary configuration. The combination of the tether, the entrained mass of the tube and the cantenary hydromechanically decouples the hydrophone arrangement from the effects of current, wind, and surface wave action acting on the other components of the sonobuoy.

Very low frequency sonobuoy (VLF sonobuoy)

Calibration of expendable sonobuoys can be made in-situ to assure the transmission of representative data. A pair of integrated circuit timers are coupled together to provide on-off duty cycles during which a spectral distribution of calibration signals is fed to the sonobuoy. Since the spectral distribution and amplitude of the calibration signals are known, a remote monitoring station is continuously apprised of the sonobuoy's calibration.

Growing community of inventors

San Diego, CA, United States of America

Thomas E Stixrud