Other

Her Majesty the Queen in Right of Canada, As Represented by the Minister

Canadian Patents & Dev. Limited

US Government As Represented by the Secretary of the Army

Canadian Patents & Development Ltd.

Elmer H Hara

R Ian MacDonald

Edward R McRae

Takeshi Ozeki

Robert I MacDonald

Jerzy A Dobrowolski

Brian S Kawasaki

Robert H Hum

Arthur L Poirier

Robert S Hum

A leakage-sensing device for installation adjacent to a pipeline configured for conveying liquid or gaseous chemical materials. The leakage-sensing device comprises a length of cable configured to transmit and back-reflect signals. The cable is communicable with a signal-measuring device. The entire length of cable is encompassed by a torsioned and tensioned coiled biasing means. The cable and the torsioned and tensioned coiled biasing means are embedded in a chemically frangible casing material. The chemically frangible material is selected for its structural instability when contacted with the selected chemical material to be conveyed within the pipeline thereby releasing the torsioned and tensioned biasing means which subsequently imparts bending and/or twisting and/or elongating and/or contracting forces to the cable thereby causing the cable to physically interfere with and/or deform and/or break the transmission and back-reflection of signals along the cable.

Pipeline leakage-sensing device

Audio signals are presented to a user by separating the audio signals into plural discrete frequency components extending from a low frequency to a high frequency, translating each of the frequency components into control signals, and applying the control signals to an array of light emitting devices for sensing by the user.

Tactile and visual hearing aids utilizing sonogram pattern

Presenting audio signals to a user is comprised of receiving audio signals to be presented, separating the audio signals into plural discrete frequency components extending from a low frequency to a high frequency, translating each of the frequency components into control signals, and applying the control signals to an array of tactile transducers for sensing by the user.

Tactile and visual hearing aids utilizing sonogram pattern recognition

A projection TV light controller is comprised of a plurality of blocks of material which are transparent to the light of a lamp, adjacent sides of the blocks being cooperatively shaped and being disposed adjacent to each other, to form a single light controlling element. The element is shaped to surround a cylindrical region coaxial with a central axis of the element for containing the lamp. Light is conducted from the lamp in each of the three primary colours into respective ones of the blocks. Apparatus is associated with each block for creating video display light signals relating to a corresponding primary colour. The video display light signals of all of the primary colours are combined into a single light beam which is conducted out of the light controlling element. With the lamp being contained in a central region, it can be cooled either by convection, by a fan, or by a fused quartz fluid jacket around the lamp, maintaining the block cool and minimally subject to expansion or contraction.

Projection TV light controller

An optical mixing/demixing device is provided comprising a series of solid, light transmitting blocks, each having opposed, front and rear parallel, planar faces, coated with optical interference multilayer coatings, and first and second light transmitting faces arranged one on each side of the front planar face. The blocks are packed side by side with a precision, light expanding and collimating lens on the first light transmitting face and further, similar precision lenses on each of the second light transmitting faces. The first and second light transmitting faces may also be coated with optical interference multilayer coatings that are pass band filters.

Optical mixing/demixing device

This invention utilizes an opto-electronic matrix switch to select a set of fixed value phase shifters. Signals which are selectively phase shifted by this apparatus may be introduced into the signal path of each antenna element of a phased array antenna. In one embodiment the input signal is converted into an intensity modulated optical signal which is then split between paths of different length to provide different delays and hence different phase shifts. The matrix then selects a particular set of the phase shifted signals which are converted back to electrical signals and fed to the antenna array elements.

Optoelectronically switched phase shifter for radar and satellite phased

Logic circuits employ photoresponsive GaAs field effect transistors to directly drive GaAs laser diodes to provide optical output signals in response to optical input signals. Since the only electrical inputs are DC bias voltages, each such circuit can be readily decoupled, such as for use in electrically noisy environments. The optical output represents a predetermined logic condition in response to a predetermined operating current applied to the laser diode as a result of the operation of the photoresponsive device. Two photoresponsive devices may be used to apply two different operating current magnitudes to the laser diode to produce two different optical output signals.

Optoelectronic logic

The optoelectronic switch includes a photosensitive GaAs FET onto which an optical signal may be directed. The optical signal is derived from an RF modulated light source. A voltage circuit is connected to the FET to switch the FET 'on' or 'off' by placing a positive or zero voltage respectively on the drain. An isolation of over 70 dB is obtained in this FET switch.

Broadband high speed optoelectronic semiconductor switch

The optoelectronic cross-point switch suitable for a broadband switching array includes a photodiode which converts an optical signal impinging upon it to an electronic signal and a biasing circuit for selectively reverse biasing the photodiode to render the photodiode responsive to the optical signal or forward biasing the photodiode to render the photodiode substantially non-responsive to an optical signal. The biasing circuit consists of positive and negative voltage sources and a controllable switch to connect the sources to the photodiode. A load circuit which is connected to the photodiode for developing the output signal may consist of a single resistor, a pair of series resistors, an operational amplifier with feedback or an rf transformer. The load circuit can also include an rf switching diode connected to the photodiode to improve isolation and to reduce the electrical power required to forward bias the photodiode.

Optoelectric cross-point switch

The present invention relates to a frequency division multiplex system for transmitting a plurality of radio frequency signals of differing frequencies from a transmission station to a receiving station. The system is comprised of a plurality of modulated light sources in the transmission station, each providing a light signal. A major optical fiber unit joins the transmission station with the receiving station for transmitting a mixed light signal comprised of the light signals from each light source. A plurality of minor optical fiber units are provided, each connecting one of the light sources to the major optical fiber. A photodetector is located in the receiver station. The detector is operatively associated with the major optical fiber for detecting the radio frequency signals from the mixed light signal.

Frequency division multiplexing system for optical transmission of

Method and apparatus is described for remote detection of location and intensity of clear air turbulence through the collection and analyses of back scattered laser light from a region where clear air turbulence may exist. The interference pattern of the collected light is determined through an ultra high resolution spectroscope and is analyzed with an image dissector. Information from the image dissector relating to the spectrum of back scattered light is correlated with the standard spectrum representing absence of clear air turbulence at the distance in question. By providing apparatus having high sensitivity and fast response, a device suitable for use in aircraft to detect clear air turbulence is provided.

Clear air turbulence detector

The present invention relates to an optical-fiber switch. The switch is used in switching between at least two optical signals which are capable of being modulated with a broadband RF signal including digital signals. The switch is comprised of at least two optical-fiber cables for feeding the at least two optical signals to at least two fixed positions. An optical-fiber output cable is provided having one end which is movable between at least two positions which are directly adjacent said two fixed positions. A drive unit is provided for moving the optical-fiber output cable between the at least two positions, whereby the optical signals are selectively fed to the optical-fiber output cable.

Growing community of inventors

Ottawa, Canada

Elmer H Hara