Abstract: A combination of two phase-lock loops, and a cancellation circuit are used to remove a dominant FM signal from within a signal environment. The two phase-lock loops together produce a replica of the highest power (i.e. dominant) FM signal. The cancellation circuit uses this replica in a demodulation, notch-filtering, and remodulation process to excise the dominant FM signal, leaving the other signal(s) undisturbed. Potential applications include co-channel FM signal/interference cancellation and optimizing utilization of RF spectrum.
Abstract: An asynchronous transmission mode (ATM) memory array capable of storing one ATM packet of data is an n x m array of memory locations, each memory location capable of storing one bit. The array has n columns, where n is the number of bits in an ATM cell of data, and m rows, where m is the number of cells in an ATM packet. The memory array has a plurality of input lines, one for each of said n columns, which together receive n bits simultaneously. It also has n ground lines, one for each of said n columns in said array, each ground line connected to one memory location in each of said n columns in its row; such that each ground line carries the current of only one bit, thereby reducing the noise transients.
Abstract: A ball bearing/freewheel clutch is provided with an inner race member defining an inner race surface; an outer race member defining an outer race surface concentric with said inner race member; and a raceway between said inner and outer races. The inner and outer race members each have a series of short radially oriented sawtooth inclines on their respective inner and outer race surfaces at right angles to said raceway. A plurality of modified ball bearings are disposed in said raceway between said inner and outer race members, such that said modified ball bearings serve to prevent relative rotation of said inner and outer race members in one direction, and to transmit a torque between said inner and outer races. In the preferred embodiment of the invention, said modified ball bearings have flattened poles which engage said sawtooth inclines in one direction of rotation.
Abstract: A secure wireless party line system that can be used by a group of mobile users to communicate with each other like a wired party line but without the cumbersome inconvenience of long wired tether. The party line function is achieved by the use of a fixed wireless repeater. The fixed wireless repeater receives spread spectrum transmissions from all N mobile users at a frequency f1, and passes the received signals through an RF amplifier and upconverter, and then to an IF amplifier and power divider, which converts the received signals down to a convenient intermediate frequency (IF), and feeds N receive spread spectrum processors, each dedicated to receive a coded spread spectrum transmission from one user. The received voice outputs from the N users are then combined in a N-channel voice data multiplexer, and broadcast at a frequency f2 to all users with a common spread spectrum code word added by a transmit spread spectrum processor.
Abstract: A tunable optical amplifier is used as a wavelength-selective high-gain element in a subcarrier-multiplexed fiber optic transmission system for providing a direct optical domain-to-baseband conversion of a selected optical channel. A high-speed diode laser optical transmitter is modulated by a plurality of independent information channels that are carried on separate, appropriately spaced carrier frequencies. An optical receiver, coupled to the transmitter by way of an optical fiber, includes a tunable narrow-bandpass semiconductor laser optical amplifier having a gain bandwidth smaller than wavelength distances between adjacent ones of the carrier frequencies, a photodetector coupled to the output of the amplifier, and polarization controlling means coupled to the fiber in front of the optical amplifier for maximizing gain in the optical amplifier.
Abstract: An asynchronous transfer mode switch with shared memory under the control of a content addressable memory, receives serially through a plurality of input ports a plurality of cells of digital data packets during a specific time period, each packet having a header. The header of each said cell is processed and temporarily stored. The data bits of each cell are temporarily stored, and transferred in parallel to a random access memory, using available addresses in said random access memory. A header processor assigns an arrival number to each received cell, and extracts the output port destination and priority of each cell from said headers. A content addressable memory stores the arrival number, output destination port and priority of each data cell. A read control provides sequentially, in order of priority, arrival numbers, and destination addresses, to said content addressable memory for determining the order in which cells of data are read from said random access memory.
February 21, 1995
Date of Patent:
April 30, 1996
GTE Laboratories Incorporated
Michael Cooperman, Phillip Andrade, Richard W. Sieber
Abstract: A spread-spectrum clock circuit is applied to microprocessor or other clocked digital electronic equipment for the purpose of reducing spectral emissions residing at harmonic and subharmonic multiples of the clock frequency. This clock randomly varies the frequency of its output within a frequency constraint bound centered at the average clock frequency. The center frequency of the spread-spectrum clock is stable and is usable for timing and measurement applications. The spread-spectrum clock is a sealed, self-contained circuit module that can be applied to existing digital electronic equipment without modification.
Abstract: A system for enhanced call delivery to a roaming cellular subscriber, enabling said subscriber to receive calls placed to his MIN in his home system service area, utilizes a central telecommunications system processor capable of handling network applications, directly connected to a plurality of mobile telephone switches located in the service areas of a plurality of cellular telephone systems, each of said switches connected via a direct communication link to said central telecommunications system processor. A plurality of registers in said central telecommunications system processor are provided for storing data bases of system information, individual switch information, and subscriber information.
Abstract: A broadband space switch matrix includes a parallel combination of individual switch modules each comprising a cascade of pass-transistor selectors, NAND gates, and inverters arranged into a multi-stage tree multiplexing configuration. The switching speed is increased by isolating each switching crosspoint from the stray capacitive loading in the matrix.
February 8, 1994
Date of Patent:
November 7, 1995
GTE Laboratories Incorporated
Michael Cooperman, Arnold Paige, Richard W. Sieber
Abstract: A solder geometry for epi-down diebonding an optoelectronic component to a heat sink platform includes a solder deposition pattern having exposure windows to create gaps or diebond bridges in the solder pattern. The active regions of the components are disposably registered within the gaps of the solder pattern.
Abstract: A novel channelized, hybrid time- and space-integrating acousto-optic (AO) spectrum analyzer is described. The architecture consists of two acousto-optic cells in a crossed cell configuration. The first acousto-optic cell is a wide bandwidth device that performs space-integrating spectral analysis and channelizes signals according to carrier frequency. The second acousto-optic cell, in conjunction with a modulated source, performs time-integrating spectral analysis of the signal envelope using the chirp algorithm. One possible application of the processor is to determine the carrier frequency and pulse repetition frequency (PRF) of received radar signals.
Abstract: A new class of multiplexing filter structure has both the properties of channelized filtering and channelized linear frequency discrimination. The channelized filter-discriminator is intended for use as part of a microwave receiving system possessing a high probability of intercept for incoming signals. The selective properties of the band pass filters provide an interference-reduction capability while the discriminator property provides for instantaneous frequency measurement. The design procedure for achieving a very high degree of discriminator linearity in association with a reasonable selectivity comparable to a maximally flat filter uses theoretical design data provided in a normalized table generated by computer optimization. A hardware realization of a 64 channel multiplexer-discriminator is described and measured data is presented that agrees very closely with the theoretical predictions.
Abstract: A system for secure communication between transmitting and receiving devices in a laser communications system using pulse position modulation, has a transmitter means to modulate and a receiver means to demodulate a transmission utilizing a protocol in which a number N (N.gtoreq.1) of optical pulses represents each symbol to be transmitted. A transmission is initiated with a trigger event. Thereafter, a multi-pulse synchronization signal is transmitted as the first symbol of each transmission, the first pulse of said synchronization symbol being transmitted within a first time frame after said trigger. A buffer in said receiver receives and stores the first of said N frames of said synchronization symbol. Each subsequently received frame of said N frames of said synchronization symbol is added to data previously stored in said buffer. A frame template is calculated from the stored pulse data of said first N pulses in said buffer and from said synchronization symbol protocol.
Abstract: A broadband omnidirectional antenna comprises a figure of revolution having an axis and two axially spaced coaxial elements with rolled radially outer edge portions and defining therebetween an antenna aperture. One element has a conically-shaped aperture-defining surface radially diverging from a plane aperture-defining surface on the other element extending perpendicular to the axis, the outer edge portions of both surfaces being curved away from each other and back toward the axis. This antenna operates over a 500 MHz to 7 GHz band with a VSWR of approximately 3:1. The invention also comprehends a method of forming the antenna elements in metallically coated molds with a fiberglass-resin mix.
Abstract: A narrow passband, reflective optical filter at a wavelength L, has a container filled with a pressurized gas, the pressurized gas having a ground state transition corresponding to the wavelength L and transparent to all other wavelengths. The container has at least one optically transparent major planar surface serving as the face thereof, whereby incoming broadband light is absorbed by the gas, except at its resonance wavelength L, which is specularly reflected. The optically transparent face of the container optionally has a broadband anti-reflective coating to improve its out-of-band rejection of unwanted wavelengths of the light signal.
May 24, 1991
Date of Patent:
June 23, 1992
GTE Government Systems Corporation, GTE Laboratories, Incorporated
Abstract: Spectrally pure optical radiation (SPOR) such as laser radiation is effectively distinguished from broadband optical radiation such as sunlight and herein called radiation of unknown spectral purity (RUSP) by apparatus including an etalon, which apparatus determines balance or unbalance between the respective portions of a signal incident on the etalon that are reflected by and transmitted through the etalon. Unbalance between the two signal portions indicates the presence of SPOR. The intensities of the reflected and transmitted radiation are compared and a determination of inequality or unbalance indicates SPOR whereas equality or balance indicates spectrally impure radiation. Measurement of the sum of the intensities of the reflected and transmitted radiation also provides an estimate of the angle of incidence of RUSP on the etalon.
Abstract: A method for remotely measuring an unknown temperature Ts of a transparent medium by comparison with the known temperature Tr of a transparent reference material consisting of the steps ofcombining the outputs of a continuous-wave (CW) laser and a high intensity pulsed laser to form a combined laser output beam, wherein the high intensity pulse component of the output beam exceeds the intensity required to produce stimulated Brillouin scattering (SBS) in the transparent medium;splitting the combined laser output beam into first and second sub-beams;amplifying the CW components of the first sub-beam to an intensity exceeding the intensity required to produce stimulated Brillouin scattering (SBS) in the reference material while simultaneously suppressing the pulse components in the first sub-beam;directing the first sub-beam with the amplified CW component into the reference material and thereby generating a CW phase-conjugate beam;directing the second sub-beam into the transparent medium and generating a pulse
Abstract: A photonic time-slot interchanger with fiber-loop delay-line memories is provided with multistage, cascade-structured integrated optical switches in the write-in, store and circulate and read-out functions to provide improved signal-to-crosstalk ratios and control tolerances, and to increase significantly the number of time slots supported by the improved interchanger.
Abstract: A foreshortened log periodic antenna comprising variously configured dipole elements and a tapered feedline is further size reduced with an improved configuration of the dipole with the lowest resonant frequency. By substantially increasing the thickness of that dipole, the overall length of the already size-reduced dipole is further decreased by 8% to 10%.
Abstract: A non-imaging optical telescope having a variable field-of-view utilizes an atomic resonance filter within its non-reflective tube. The atomic resonance filter received incoming light through the aperture of the telescope and re-emits the light to an optical sensor. The field-of-view is a function of the distance of the atomic resonance filter from the aperture. A positioning mechanism is provided to move the atomic resonance filter within the tube, thereby varying the field-of-view.