Bell Telephone Laboratories

At&t Bell Laboratories

Lucent Technologies Inc.

Bruce E Briley

John Montsma

Mikiel L Larson

Jeffrey A Hiltner

A terrestrial wireless telecommunication system is disclosed that uses an electronic scanning antenna to rotate a beam that carries communication messages between a base station and a plurality of wireless terminals. A base station transmitter transmits the communication messages to each wireless terminal, via the electronic scanning antenna, in a time-division multiplexed (&ldquo;TDM&rdquo;) data stream that is synchronized with the rotation of the beam, and a base station receiver receives the communication messages from each wireless terminal in a time-division multiple access (&ldquo;TDMA&rdquo;) data stream that is also synchronized with the rotation of the beam.

TDM/TDMA wireless telecommunication system with electronic scanning antenna

A structure connecting superconductor transmission lines to integrated circuits comprises a plurality of interconnection substrates having superconducting transmission path deposited thereon in contact with metallic contact areas, and integrated circuit chip carrier substrates for mounting integrated circuits and having metallic contact areas. The substrates are mounted in a retainer structure and are separated by spacers which have apertures in registration with the contact areas. Contact devices are selectively inserted in the apertures to establish an interconnection pattern between the substrates. The retainer structure applies force to the substrates to assure physical contact between the substrates and the contact device. The structure may be assembled and disassembled for replacement of parts or reconfiguration of interconnections, without the application of heat or other processes which are incompatible with relatively brittle and heat sensitive superconducting materials. The complete structure may be submerged in a bath of liquid nitrogen for cooling. The space provided by the spacers allows for access by the cooling liquid to the superconducting material on the substrates.

Superconductor interconnection apparatus

An electronic system having components operating at low temperature at various locations within the system, cryogenic fluid and electrical power are distributed by means of the same conduit. In one embodiment, the conduit consists of a supply section and a return section with each section comprising a channel for conveying cryogenic fluid having superconducing walls for conveying electrical power. In another embodiment of the invention, the conduit comprises a copper rod having channels formed therein for the transport of cryogenic fluid and a channel for supporting a rod of superconducing material therein. The superconducing rod conducts electrical current to a subsystem while being cooled by cryogenic fluid in nearby channels and the cryogenic fluid is used at its destination for cooling purposes. In yet another embodiment of the invention, cryogenic fluid is transported between a source of cryogen and subsystems using the fluid, by means of a pair of concentric conduits with the walls of each conduit comprising superconducting material for simultaneously providing electrical power to the subsystems employing the cryogenic fluid.

Superconducting bus bar

A switching array comprising low power switching elements for switching high bandwidth pulse encoded signals with minimum distortion. Each switching element comprises an emitter-coupled pair of transistors which are used to switch the pulse encoded signals. The pair of transistors are enabled and disabled by inhibiting the flow of electrical current through the latter. A transistorized switch controls the electrical current in the pair of transistors in response to signals from a control register within the switching array. Since no current is flowing in the pair of transistors when the element is inhibited, the power dissipation approaches zero in the inhibit state resulting in an overall low power dissipation for the switching array since only a small number of elements are normally enabled at any time. Each element further comprises an emitter-follower transistor for the purpose of isolating the pair of transistors from the remainder of the switching array in order to reduce the crosstalk between pulse encoded signals.

Low power wideband switching array element

A time division multiplex (TDM) switching network is disclosed in which at least part of the network comprises a space switching portion (TMS) and in which the need for duplication of the space switching portion, and like methods of achieving network reliability, is eliminated. Data from an incoming channel is partitioned into successive blocks, a prescribed number of which form a set of blocks. The blocks are of predetermined size. Each of the blocks of a set is switched via different paths of the space portion of the network. A single network fault can therefore cause the loss of only one block of data in a set. This loss can be made insignificant in the case of data representing telephone conversations. For data not representing telephone conversations, error checking and correcting information is added to the set before transmission through the space portion of the network and errors occurring during transmission are corrected thereafter.

Time division switching system

An optical transmission arrangement includes a transmitter which transmits an electrical analog input signal as two separate optical signals through a pair of optical fibers to a receiver. Combining the two optical signals, the receiver generates an electrical analog output signal representative of the input signal, absent even harmonic frequency components which may have been introduced in transmission.

Optical communication arrangement

An adder circuit for generating a completion signal indicating the completion of adder operation. A detector circuit (103) is connected to the power supply bus (102) of a multistage parallel adder for detecting voltage variations caused by the operation of the adder stages and for generating a completion signal when these voltage variations have ceased to occur for a predetermined period of time.

Asynchronous adder circuit

A method and circuitry are disclosed which allow the operation of carbon microphones in telephone sets at low levels of average current. The microphone is connected to a pulse-generating circuit which energizes the microphone with pulses of current that effectively sample the incident acoustic signal at a superaudible rate. The level of each current pulse is chosen so that the microphone performs at the high signal-to-noise ratio associated with high current levels and the duty cycle is chosen to match the low average value of available current. The audio signal is recovered by demodulating the resulting PAM (voltage) output signals using a low pass filter. The level of the recovered audio signals is then amplified to the level required by the telephone transmission line. The sampling approach, using the carbon microphone as the sampling element, extends the utility of the carbon microphone to operation at low average current levels which hitherto were unusable because of low signal-to-noise ratio. This method may also permit a uniform reduction in current levels on all the lines of an associated telephone central office thereby reducing total power consumption and allowing the use of higher resistance, fine gauge transmission loops.

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Countryside, IL, United States of America

Bruce E Briley