Abstract:
A multiprocessor system (20) comprises a plurality of stations (22a-22d) interconnected by a system communication bus (21) and cooperating in the performance of system tasks. Each station includes a plurality of addressable elements (c-k) interconnected by a station communication bus (b). All stations are mapped into a common address space (1001a), with the elements of each station mapped onto like relative addresses in two subspaces (1002a-r) of the address space: a subspace which is shared in common by all stations, and a subspace dedicated to the station whose addresses are the common subspace addresses in combination with a station identifying address portion. The stations are symmetrical: like elements in all of the stations are mapped onto like relative addresses in their associated subspaces. Addressing within the system is self-referential: a station accesses one of its addressable elements by placing its common subspace address on the station communication bus. Each station's station bus (b) is selectively interfaced (a) to the system bus (21), and a station accesses an addressable element of another station by placing its dedicated subspace address on the station bus, interfacing its station bus with the system bus, and causing the other station to interface its station bus with the system bus. A station accesses an element of another station passively, without utilizing the intelligence, if any, of the other station to make the access.
Abstract:
A tone receiver suitable for use in a telephone system and which adaptively narrows its amplitude sensitivity range defining valid tone signals on a per call basis in accordance with the amplitude of a first tone signal received on a call. The signal range adaptability improves signal echo rejection and spurius noise talkoff. A preferred embodiment is implemented by a programmed digital signal processor which increases the lower amplitude signal threshold in accordance with the amplitude of the first signal. An alternative embodiment adaptively attenuates the level of incoming signals before signal validation. A further improvement of both embodiments allows further amplitude range narrowing in response to any subsequent signal on a call which has an amplitude greater than that of any preceding signal in the call.
Abstract:
A demultiplexer circuit which extracts from an incoming time division multiplexed digital bit stream any combination of pulse-code modulated (PCM) encoded words or data bits, irrespective of their rate or the position of the data bits in a given channel or channels. The demultiplexer circuit includes a random access memory (RAM 12) for storing address information as to the bit or bits to be demultiplexed out of the incoming digital bit stream (lead 15). A counter (13) operates in synchronism with the received bit stream and the output thereof serves to access the RAM to provide output signals indicative of the bit(s) carrying information for the subscriber station. These output signals are utilized to read the digital signals intended for said station into other RAMs (31, 41). A summing circuit (16-19) is coupled to the input of said other memory so that conference calls are summed in real time. The digital signals are then read out of the other memory at a steady rate, with a stored data signal being similarly outputted irrespective of the rate of the signal or its position in a given channel or channels.
Abstract:
Method for controlling the interconnecting of a plurality of local communications networks. A source station (30-1) and a destination station (30-N) may respectively be adapted to be coupled to at least one of a plurality of local data networks (10). The respective stations are adapted to determine the home network of the other respective stations with which the respective stations may communicate. Broadly, a source station (30-1), which has message to transmit to a destination station (30-N), determines the home network (10) of the destination station and couples a first source receiver (100) and a source transmitter (100) to the home network of the destination station for transmitting a packet from the source to the destination. A first packet may be transmitted when the source station (30-1) acquires access to the destination home network. Further packets may be transmitted, not on the destination home network, but rather on the source home network. The source transmitter (100) may be decoupled from the destination home network (10) for such further packet transmission.
Abstract:
In an arc discharge device, a thin film (200) bridges the gap(s) between adjacent electrodes (201, 202), thereby enabling the arc discharge to be initiated and sustained by a low voltage D.C. supply. One embodiment utilizes a cathode electrode which includes a pool of liquid Hg to generate a Hg ion plasma.
Abstract:
A transducer embodying the present invention is assembled on a discrete electrically conductive frame (100) that has been formed to provide both leads (120-140) and a backplate (110). An integrated circuit chip (200) is bonded to one of the leads, and a dielectric inner housing member (300) is molded about the backplate and the portion of the leads adjacent to it. The inner housing member encapsulates the chip, embraces the perimeter of the backplate, and provides a cylindrical opening (310) that extends on each side of the backplate. A conductive outer housing member (400) is subsequently molded about the perimeter of the inner housing member, and a spacer (500), electret diaphragm assembly (600), and conductive gasket (700) are sequentially positioned in the opening on one side of the backplate. Conductive front and back covers (800, 900) are thereafter bonded to the outer housing to close the opening and to complete a conductive enclosure that provides electrostatic shielding for the transducer. In addition, electrical continuity is provided between a metalized surface on the electret diaphragm and the conductive enclosure by means of the gasket.
Abstract:
A time division switching system having a plurality of time-slot interchange units (11, 12) interconnected by a time multiplex switch (10). Each time-slot interchange unit includes a controller (17, 18) which communicates with other controllers through the normally speech and data conveying time multiplex switch. The time multiplex switch comprises a pair of switch matrices (205, 206) each of which is connected to all time-slot interchange units. Additionally, switch matrices are interconnected so that information at a particular output of both switch matrices is directly connected to an input of the other switch matrix. When communication is requested between two time-slot interchange units, a path is sought over the connections between the two time-slot interchange units and the same switch matrix. If no such path can be found, a path is sought to the two separate switch matrices and communication between the two switch matrices is maintained over the connection between them.
Abstract:
A mechanized system distributing the access, test and communication functions to the point of testing, typically the centralized switching facility or wire center (150, 151) serving the customer loops to be tested. Computer (200) stores information about each customer loop in the geographical area served by a system. Front-end computers (220, 221) interact with computer (200) to retrieve pertinent data regarding loops to be tested. Each switching facility in a area includes a loop testing system (e.g., 160) that implements the required functions. The communication functions residing in front-end computers (220, 221) and loop testing systems (160, 161) are coupled via a data communication network (140) in a manner that allows any front-end computer to communicate with any loop testing system. Users of the system control access and test from consoles having the capability of establishing independent communication paths over the national dial network for interactive tests on loops accessed through standard test trunks. Microprocessor-based circuitry is utilized for numerous system tasks such as signal generation, digital signal processing and controlling sensitive analog measurements. Signal generation includes digital generation of analog waveforms. Signal processing techniques incorporate various digital filters to analyze sample sequences derived from, for example, dial pulses and coin telephone signals. Sensitive analog measurements of loop characteristics are effected with a magnetic current detector that operates over broad current and frequency ranges. Frequency dependent measurements are converted to DC using synchronous demodulation techniques to enhance resolution.
Abstract:
A compatible high-definition television (CHDTV) color picture signal which is capable of conversion by simple and inexpensive means into either a HDTV composite color picture signal for use by a HDTV receiver or an associated conventional television system (ACTS) color picture signal for use by an ACTS receiver. The present CHDTV color picture signal comprises (a) a first line scan rate which is the same as that of the ACTS signal, (b) a first line signal of a HDTV camera signal produced at a second line scan rate which is time stretched and transmitted as is at the first line scan rate in a first portion of the CHDTV signal bandwidth, and (c) a second line signal of the HDTV camera signal which is time stretched and transmitted as a line differential signal on a vestigial sideband carrier signal in a second portion of the HDTV signal bandwidth.
Abstract:
A communication method and packet switching system in which packets comprising physical addresses and voice/data information are communicated through the system by packet switching networks (116) which are interconnected by high-speed digital trunks (118) with each of the latter being directly terminated on both ends by trunk controllers (131, 140). Customer terminals (100) are connected to the switching system by access line controllers (112a) which insert the physical addresses into the packets. The line controllers attach to concentrators (112) which are interconnected to the switching networks via high-speed digital trunks (117). During initial call setup of a particular call, the physical addresses are obtained and stored in the line controllers by the transmission of a call setup packet and call reply packet between the originating and destination line controllers. Each processor (111) inserts into the call setup packet the necessary addressing information to route packets through the associated network. Each network comprises stages of switching nodes which are responsive to the physical addresses in a packet to communicate this packet to a designated subsequent node. The nodes provide for variable packet buffering, packet address rotation techniques, and intranode and internode signaling protocols.