Network communication protocol including a reliable multicasting technique
Granted: March 22, 1994
Patent Number:
5297143
An improved network for communication of message packets. The present invention provides for improved reliable multicast messaging wherein messages may be reliably multicast to members of a multicast group and acknowledgements may be handled in an improved and efficient manner. In particular, a message may be transmitted to all members of a group, each member of the group responding to receipt of the message with an acknowledgement message. Further, facility is provided to allow for…
Transmission mode detection in a modulated communication system
Granted: February 22, 1994
Patent Number:
5289476
A power line communication (PLC) apparatus wherein transmission mode information is encoded into each data packet while maintaining immunity from single bit errors. In the present invention, a power line communication system includes a transmitter/receiver (i.e. transceiver) which is coupled to a power distribution network. Data is transmitted through the power line by the transceiver in packets. The transceiver includes a preamble generator which creates a preamble for each of the data…
Adaptive data recovery for spread spectrum systems
Granted: February 22, 1994
Patent Number:
5289498
A method and means for for recovering data in a spread spectrum communications system. The present invention includes a method and means for providing a sync window time period. The sync window is set to encompass the correlation values which are generated one baud time from the previous recovered data bit. The present invention also determines the peak correlation value within the sync window and the location in time within the sync window that the peak correlation value occurs. The…
Adaptive threshold in a spread spectrum communications system
Granted: November 16, 1993
Patent Number:
5263050
A transceiver for transmitting and receiving spread spectrum signals having an adaptive threshold for distinguishing between valid receive data signals and noise. The transceiver includes a transmitter for transmitting spread spectrum signals and a receiver for receiving spread spectrum signals. A correlator correlates a received signal against an expected receive pattern. The correlation of the received signal is compared to a threshold value. If the correlation exceeds the threshold…
Adaptive carrier detection
Granted: November 9, 1993
Patent Number:
5260974
An improvement in an apparatus which uses a carrier detection threshold level for detecting a carrier signal modulated with binary data. The threshold level is dynamically changed and generally seeks a level above the background noise. The threshold level is maintained constant when the detected signal exceeds the threshold level. An evaluation circuit is able to examine the detected signal to determine whether it contains data or only noise, and if it contains only noise, a possible…
Method and apparatus for power line communications
Granted: October 26, 1993
Patent Number:
5257006
A method and apparatus for power line communications which utilizes common mode transmission and reception of communication signals over power lines. The communication signals are sent and received between the power and neutral lines, and the ground line. A common mode choke in the power lines presents a relatively high impedance to the communication signals and prevents them from being shorted to the ground line. The choke is substantially transparent to the power delivery current.
Development system protocol
Granted: September 28, 1993
Patent Number:
5249270
The present invention works in combination with an integrated set of hardware and software tools that support rapid design, programming, debugging, implementation, and testing of local operation network local operation network nodes and applications. These hardware and software tools speed development by enabling developers to use object-oriented concepts, such as network variables and input/output objects, rather than low-level constructs. The development environment operates with an…
Drive amplifier for power line communications
Granted: August 31, 1993
Patent Number:
5241283
A power line communication amplifier circuit for providing a signal transmission across a power line medium when operating in a transmit mode, and for providing a relatively high input impedance to the power line when in a receive mode includes a unity gain buffer integrally coupled with a filter. The filter operates upon an input signal provided by a digital driver means. A control means is coupled to the digital driver means and to the buffer such that when said amplifier is switched…
Transceiver with rapid mode switching capability
Granted: August 24, 1993
Patent Number:
5239686
An RF transceiver achieves a fast switching time between transmit and receive modes by leaving the transmit oscillator on all the time. The transmit chain comprises a wide pulling voltage controlled crystal oscillator that operates at one third the transmit frequency followed by a frequency tripler/filter/amplifier chain that can be quickly switched on and off. By operating the transmit oscillator at one third the transmit frequency, only the third harmonic of the oscillator falls into…
Apparatus and method for reducing errors in data caused by noise
Granted: May 11, 1993
Patent Number:
5210518
In a power line communications apparatus an improvement for blanking or snubbing impulse noise. The impulse noise is detected and used to snub the detected signal. The duration of the snubbing pulses is controlled to assure complete blanking of noise including the trailing noise signals following a main noise pulse which may not otherwise be detectable. Also, the number of snubbing pulses which can occur are limited to prevent too much energy from being snubbed during any given baud…
Printed circuit radio frequency antenna
Granted: April 27, 1993
Patent Number:
5206657
A radio frequency antenna comprises a pair of double-sided printed circuit boards that are etched on each side to form conductive loops around the periphery of each board. The circuit boards are spaced apart by standoffs and the loops are electrically coupled in series. An impedance matching network is incorporated on one of the circuit boards.
Computer architecture for conserving power by using shared resources and method for suspending processor execution in pipeline
Granted: April 13, 1993
Patent Number:
5203003
A computer architecture and method capable of retaining data after a system clock has been halted to conserve power. The computer comprises first processing circuitry, the first circuitry comprising dynamic components. The dynamic components include such devices as intermediate pipeline registers, arithmetic logic units, address generators, and instruction decode and control circuitry. The computer further comprises second processing circuitry, the second circuitry comprising static…
Binary data error correction using hint signal
Granted: March 16, 1993
Patent Number:
5195098
An error detection and correction method and apparatus is described which permits the correction of double errors using a (15,11) Hamming code and a parity bit. The Hamming code and parity bit allows the detection of double errors. A modulated waveform carrying the binary data is examined for anomalies such as noise pulses. A hint signal is generated based on the anomalies which points to a suspect bit. The state of this bit is changed to correct for double errors.
Power line communications coupler
Granted: March 9, 1993
Patent Number:
5192231
A coupler for providing coupling for power line communications between the power lines carrying different phases of the power. The coupler engages an ordinary wall outlet such as 220 volt outlet and includes a receptacle for a 220 volt plug. Internally, the adaptor has high frequency coupling between the power lines. The coupling presents a high impedence to the power signal.
Transceiver providing selectable frequencies and spreading sequences
Granted: February 23, 1993
Patent Number:
5189683
A transceiver the transmitting and receiving digital data is disclosed. The transceiver employs direct sequence spread spectrum communications techniques for reducing interference among multiple users in a communications network environment. Each transceiver has a transmitter for locking a digital bit stream to a predetermined spread spectrum chip sequence and carrier signal. Frequency of the carrier signal and the chip sequence. Both the carrier signal, the chip sequence and the bit…
Data communication network providing power and message information
Granted: September 15, 1992
Patent Number:
5148144
A data communications network for delivering power and communications over the same cable bundle includes a plurality of communications nodes wherein associated with each of the nodes is a transformer having a core, a primary winding and a secondary winding. The secondary winding has a centertap connection which either splits or merges the current in the secondary winding to eliminate net DC flux within the transformer. A DC/DC converter is also included for transforming the relatively…
Correlator for spread spectrum communications systems
Granted: September 8, 1992
Patent Number:
5146471
An improved correlator for use in a spread spectrum communications system which operates with a predetermined chip sequence includes an N-stage correlation register, wherein each stage corresponds to a signal chip in the sequence, an a means for autocorrelating each of the N stages with the corresponding chips in the sequence. The correlator further includes a means for modifying the sequence to accomodate multiple communication channels.
Input/output section for an intelligent cell which provides sensing, bidirectional communications and control
Granted: May 12, 1992
Patent Number:
5113498
A network for providing sensing, communications and control is described. A plurality of intelligent cells each of which comprises an integrated circuit having a processor and input/output section are coupled to the network. Each of the programmable cells receives when manufactured a unique identification number (48 bits) which remains permanently within the cell. The cells can be coupled to different media such as power lines, twisted, pair, radio frequency, infrared ultrasonic, optical…
Multiprocessor intelligent cell for a network which provides sensing, bidirectional communications and control
Granted: July 23, 1991
Patent Number:
5034882
A processor is described which is particularly useful in a cell which cell forms part of a network for sensing, communicating and controlling. The processor includes a plurality of sets of registers, each associated with a different processor. Each set of registers shares a single ALU. Data associated with each set of registers is simultaneously moved through a path which includes the registers, ALU, and memory.
Transceiver providing selectable frequencies and spreading sequences
Granted: July 2, 1991
Patent Number:
5029180
A transceiver for transmitting and receiving digital data is disclosed. The transceiver employs direct sequence spread spectrum communications techniques for reducing interference among multiple users in a communications network environment. Each transceiver has a transmitter for locking a digital bit stream to a predetermined spread spectrum chip sequence and carrier signal. Frequency of the carrier signal and the chip sequence. Both the carrier signal, the chip sequence and the bit…
