USA as Represented by Secretary of the Navy

James D Hagerty

Anthony B Bruno

Promode R Bandyopadhyay

Rolf G Kasper

Gabriel A Rodriguez-Rivera

A phase correction apparatus includes an inductor joined to a series capacitor to produce phase-corrected output having a load voltage and a load current. A phase detector is joined to the series capacitor and has a phase angle output proportional to a phase angle between the voltage and current. Logic circuitry or a processor is joined to receive the phase angle output and provide switch control value outputs to switches connected to the logic circuitry. A bank of parallel capacitors are joined to the switches. The switch control value outputs activate joined parallel capacitors to adjust reactance provided to the phase-corrected output to produce an adjusted output. In a further embodiment parallel capacitors are iterated to produce the adjusted output.

Optimized, automatic impedance-matching system

A sample clock source includes a master oscillator providing a square wave at a predetermined frequency. A counter and at least one flip-flop are joined to receive the square wave and produce several different output square waves having reduced frequencies. A selector is provided to allow user selection of the different square waves. The selected square wave is provided to a pulse generator which produces a pulse having a known duration at the selected reduced frequency. The pulse generator output can be buffered and provided as the sample clock source. The buffer amplifier is designed to drive long cables with sufficient stability a signal fidelity.

Sample clock source for digital data systems

The invention is a method, described with the appropriate auxiliary electronic circuitry, for compensating the effect of the earth's magnetic field on Giant Magneto-Impedance magnetic sensors. The method as taught is an alternate way of cancelling out the effect of the very large residual earth's magnetic field using an impedance-tuning circuit (i.e. electrical compensation) rather than the usual magnetic type of compensation.

Impedance compensation method for giant magneto-impedance magnetic sensors to null out the terrestrial residual magnetic field

A digital counting circuit with multiple outputs is used to clock interlaced 16-bit data words into separate digital-to-analog converters in the correct sequence for each of eight hydrophone channels. The circuit utilizes a programmable memory to detect a synchronizing bit pattern.

Synchronous demultiplexer circuit and method

A data transmission system includes a serial A/D converter and a transmission processor. Transmission processor provides control signals to the A/D converter and first and second transmitters. The first transmitter is joined to the A/D converter to transmit a sync signal at a first frequency. The second transmitter is joined to transmit serial digitized data at a second frequency. First and second receivers are used to receive these frequencies. A reception processor is joined to the first receiver to activate a D/A converter on receipt of the sync signal. The D/A converter then converts digitized data received by the second receiver back to analog format. A method is also provided for transmitting and decoding the digital data.

Wireless serial data transmission method and apparatus

The present invention is an electrical circuit for a sensor designed to detect external magnetic fields. The circuit is composed of a stable voltage reference source, connected to a low frequency amplifier where the operating point of the amplifier depends on the voltage reference source that is biased for maximum allowable voltage swings of the amplifier. A GMI fiber is connected to the low frequency amplifier and to a crystal oscillator that generates a square wave excitation signal with which to excite the GMI fiber. A decoupling network connected to the amplifier allows stable excitation of the GMI fiber by separating the direct current paths of the amplifier from the excitation signal. When the GMI fiber is excited by the square wave signal the GMI fiber impedance varies with impressed magnetic fields, which in turn varies the output voltage of the amplifier.

Low-power giant magneto-impedance magnetic detector that utilizes a crystal controlled oscillator

A wireless hydrophone system includes a hydrophone joined to a preamplifier. A serial A/D converter receives the amplified hydrophone signal and provides a serial digital output representative of the signal. The A/D converter is joined to a processor which provides a start signal and a clock signal to the A/D converter. A digital transmitter is also controlled by the processor. The transmitter receives the serial digital output from the A/D converter for wireless transmission over an antenna. The system can also include logic for allowing the processor to provide an extended sync signal for transmission. The extended sync signal can alert a receiver to an initial transmission. The system can be incorporated in a hull treatment for positioning on a vessel's hull.

Wireless radio frequency hydrophone system

A wireless power transmission and communication network that provides efficient interrogation and powering of sensors for use on undersea vehicles. The present invention employs a wave-guide that allows the propagation of electromagnetic waves through a dielectric material that covers the exterior of an undersea vehicle's hull. Embedded within the dielectric material is an N dimensional array of Micro Electronic Mechanical Systems sensing devices coupled with radio frequency (RF) decoders and transceivers, and strips of conductive metal tape. Electromagnetic waves such as microwaves propagate through the dielectric material both powering the sensor network and addressing and interrogating individual sensing devices. The sensing devices take readings and then format and transmit the data results back across the wave-guide where they are received and processed by a digital processor within the hull of the undersea vehicle.

Data communication and power transmission system for sensing devices

A system and method are provided to supply power to and to communicate with an array of remote devices. The remote devices can be acoustic sensors or types of remote devices. In a preferred embodiment, the system includes a microwave source/signal demodulator that supplies wireless power and provides data interrogation signals to the sensors. The microwave transmission line is of a stripline construction. The source/demodulator radiates power to the sensor transceivers and receives data from the sensors. The source/demodulator can transmit sequential interrogation signals to activate address-selectable sensors. The source/demodulator may also decode received signals returning from the sensors. The stripline may be attached to a vessel's hull beneath a hull treatment layer and the sensors mounted on the surface of the hull treatment.

System and method for connecting with a network of sensors

A remotely controllable signal device, such as a buoy which may be used as target for gunfire training includes platform, a radio receiver, a decoding device, and one or more visual location signaling devices. The platform is floatable in the case of a buoy. The visual location signaling devices provide a visual indication of the location of the device. The visual location signaling devices include smoke generating devices such as marine smoke canisters, and a light such as a strobe light. The light can be mounted on a short tower for higher visibility. The decoding device can be a dual-tone multiple frequency decoder, and can include a switching device which selectively activates one of a number of visual location signaling devices located on the platform. The radio receiver may be a UHF AM receiver. The platform can also include a Global Positioning System transceiver device to assist in tracking the platform in the open ocean. As another option, the platform can include a sonar pinger to allow acoustic tracking of the impacts of shells when implemented as a buoy on instrumented hydrophone tracking ranges.

Remotely controllable signal generating platform

A preamplifier and pre-emphasis network is provided having a differential plifier exhibiting common mode noise rejection. The preamplifier is particularly suited for use with a double-sided sensor element and it includes a double-sided, balanced calibration circuit. First and second variable gain buffers are joined to the differential amplifier for preventing current noise degradation at the differential amplifier inputs. A pre-emphasis network is further provided in conjunction with the variable gain buffers for providing balanced differential gain of the sensor element signal. Further elements of the invention provide for high and low pass filtering, and differential buffering of the output signal.

Differential preamplifier and pre-emphasis network

The balanced, bi-directional calibration circuit of the present invention joined to a sensor and a differential preamplifier. The sensor has two outputs which are received by the differential preamplifier such that common-mode line noise is rejected. The calibration circuit includes a broadband signal generator which provides the calibration signal. The calibration circuit also includes a switching network that allows the calibration signal to be switched to either of the two sensor outputs or isolated from the sensor and preamplifier. A dual-state switching control signal is applied via a single control wire to the switching network to select which preamplifier input receives the calibration signal. The calibration signal generator control line is electrically isolated from the preamplifier by an opto-isolator. The electrical balance of the bi-directional calibration circuit and electrical isolation of the calibration signal generator preserve the common-mode noise rejection of the differential preamplifier.

Balanced, double-sided calibration circuit for sensor element and

A remotely controlled radio telemetry buoy serves as a communication link tween an underwater acoustic interrogation/receiving transponder system and a remotely located surface platform. The buoy houses a transmission device, a transceiver device and a controller. The transmission device transmits data received from the transponder system as electromagnetic energy in a frequency range of 162-173 MHz. The transceiver device exchanges digital control signals between the surface platform and the buoy in the frequency range of 2-16 MHz. The controller transfers the control signals between the transceiver device and the transmission device and the transponder system.

Radio telemetry buoy for long-range communication

An insulated mounting support is provided for installation near a feedpoint f a ladder-line transmission line. A first plate of electrical insulator material has a face from which two bosses extend, and has opposing sides abutting the face from which first and second appendages extend. A second plate of electrical insulator material has two recesses in a face thereof for mating engagement with the two bosses. The two bosses are maintained in a spaced apart relationship in correspondence with two cutouts provided in the transmission line. When the first plate and second plate are sandwiched about the transmission line near the feedpoint, the two bosses extend through the two cutouts and engage the two recesses. In this way, tension in the transmission line is absorbed by the two bosses. In addition, the first and second appendages respectively coact with first and second conducting wires extending from the transmission line at the feedpoint. In this way, tension applied to the first and second appendages is absorbed in the first plate.

Insulated mounting support for ladder-line

A circuit for amplifying an input signal comprises an operational amplifi a dual operational amplifier, and a buffering operational amplifier all cascaded in the aforementioned order. The first operational amplifier amplifies the input signal with minimum noise degradation, is set up as a non-inverting amplifier stage, and has a local negative feedback loop comprising a resistor and capacitor in parallel. The dual operational amplifier has two amplifying devices. One device forms a second amplifying stage which increases the gain of the pre-amplified input signal and has a local negative feedback loop comprising a resistor. The other device is a third operational amplifier which combines with the buffering operational amplifier to form an amplifying and buffering stage. The third operational amplifier connects in series to the output of the second amplifying stage. The buffering operational amplifier connects in series to the output of the third operational amplifier and buffers the amplified signal at this output. The amplifying and buffering stage has a two-stage feedback loop comprising a resistor connected between the output of the buffering operational amplifier and the inverting input of the third operational amplifier. A four-stage feedback loop includes a resistor and capacitor in parallel and connects between the output of the buffering operational amplifier and the inverting input of the first operational amplifier.

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Tiverton, RI, United States of America

James D Hagerty