Motorola Corporation

Adtran Gmbh

Universal Data Systems, Inc.

Avocent Corporation

Centillium Communications, Inc.

Adiran, Inc.

Centilliune Communications, Inc.

Steven R Blackwell

Richard Lee Goodson

Ayman Ghobrial

Kevin W Schneider

Jason N Morgan

Philip M Kirshtein

Christopher L Thomas

Charles E Polk, Jr

David Paul Nelson

Mickey C Rushing

David H Stafford

Paul D Durden

John Timothy Pearson

Cynthia Lin

James Vernon Pursel

Guozhu Long

Fred Chu

Jalil Kamali

Michael D Turner

Timothy Allan Johnson

W Stuart Venters

Douglas D Reed

Syed Abbas

Fred T Y Chu

David E Wilder

Trevor Pearman

Richard A Gautreaux, Ii

Sathi Perumal

Richard A Beichler

Michael D Fanning

C C Fridlin

Charles C Fridlin, Iv

Simon Huang

Peter O Brackett

Steven E Turner

Jerry D Moore

Steve Polge

Danny Windham

Melvin Bruce

A improvement to video compression techniques is described in which blocks of video input information are compared in their respective pixel values to corresponding blocks of immediately preceding frames. The blocks are analyzed to determine whether change has occurred in accordance with two tests. First, the pixel values of the block are compared to the pixel values of a preceding block and if a threshold number of pixel values in the block exceed their counterparts by a threshold amount, then the block is assumed to have changed and is communicated via a standard communication protocol, compression technique and media. Second, even if the threshold number of pixels in the block has not changed, the pixel values are compared with their prior frame counterparts to determine if any one pixel value has changed in magnitude more than a second threshold amount. Again, one such pixel is identified, then the block is assumed to have changed and is communicated.

Video compression system

In a KVM system, a system provides for USB devices to be accessed by target computers. A KVM switch connects a client with a target server via a network, the client computer having at least one device attached thereto. A second mechanism connects to a USB port of the target and communicates with the target using a USB protocol. A client mechanism communicates with the second mechanism via the network. A virtual media mechanism enables the target server to access the USB device attached to the client.

Virtual media systems, methods and devices

Techniques for carrying out multi-pair mode transmission in a DSL system are disclosed. A data stream is transmitted to a receiving node on two or more bonded channels. At the receiving node, the bonded channels are processed to yield the original data stream. Differential delay between the two or more channels of the bond group is dynamically neutralized by keying on the channel having the greatest latency, although static mechanisms for neutralizing the differential delay can also be used.

Channel bonding in SHDSL systems

A timing loop is used in a data communications receiver to time lock the receiver to a transmitter sending data across a communications loop, where the receiver includes a linear equalizer for correcting signal distortion associated with the communications loop. The timing loop includes a timing equalizer filter functionally positioned to provide an equalized signal to the phase detector portion of the timing loop. After the linear equalizer trains, the equalizer coefficients are copied to the timing equalizer.

Timing loop and method filter for a digital communications system

The present invention relates to an improved method and apparatus for echo cancellation in a communication system utilizing a bidirectional transmission medium. The invention significantly reduces computational overhead associated with echo cancellation by using sub-Nyquist sampling in the echo path. In particular, the invention relates to a method and apparatus for echo cancellation in a communication system utilizing different signaling or baud rates in the transmit and receive directions, whereby the computational overhead of the echo cancellation is significantly reduced as compared to traditional methods. In a preferred embodiment herein, the present invention reduces by one-half the computational overhead associated with echo cancellation in a data communications system utilizing symmetrical information rates at asymmetrical signal rates.

Method and apparatus for echo cancellation

A method of training and operating a dual-duplex, four-wire communications system to provide for time alignment in the receivers of data that is time aligned in the transmitters, even in the presence of a differential transmission delay in the wire pairs. In a training mode, a known sequence of training data is concurrently sent across each wire pair such that equalizers in the receivers are forced to train together. After the equalizers have been trained to eliminate the differential delay, the system is switched to a data mode.

Timing device and method using a timing equalizer filter for a digital communications systems

The present invention provides techniques for performing loop diagnostics in DSL communication systems.

Loop diagnostics for ADSL systems

A method and apparatus for providing a precoder filter having peak-to-average ratio (PAR) controller that also serves as a high-pass, low-pass, or band-pass filter. The described invention is includes a modulo device connected in series with the PAR controller and a precoder filter connected in a feedback arrangement. The input to the apparatus is a sequence of data symbols and the output is a spectrally shaped precoded signal having a controlled peak-to-average ratio.

Method and apparatus for nonlinear filtering and controlling the peak-to-average ratio

A system and method for transmitting data over a twisted pair with or without load coils using a transmitter and receiver is disclosed. The system detects load coils by generating and transmitting a test signal having signal power concentrated in two different frequency bands across the twisted pair and comparing the signal power of the received signal to determine whether the twisted pair is loaded or unloaded. If load coils are detected, an adjustment circuit is used to configure the receiver for reception of data over a twisted pair having load coils. Otherwise, the adjustment circuit configures the receiver for reception of data over a twisted pair without load coils.

System and method for transmitting data over loaded and unloaded twisted pairs

A fiber quadrupler device and method multiplexes the four optical fibers in a synchronous optical network (SONET) ring into a single linking fiber for full duplex optical transmission. The fiber quadrupler device optically couples two of the SONET fibers to a transmit converter for communications of downstream data from the SONET ring to a network element linked to the quadrupler by a single linking fiber. Two other SONET ring fibers are optically coupled to a receive converter for communications of upstream data from the network element over the single linking fiber to the SONET. An optical transceiver processes and directs the downstream and upstream signals to the receive and transmit converters. Either subcarrier modulation (SCM) or wavelength division multiplexing (WDM) is used in the receive and transmit converters.

Fiber quadrupler device method for providing full duplex communications to a synchronous optical network over a single optical fiber

A distortion compensation filtering mechanism for a direct spread-spectrum radio receiver comprises an iteratively adaptive FIR filter installed in the received signal processing path of the radio just upstream of the despreading function. The filter may be implemented as a relatively small numbered tap filter, having its precursor tap fixed at a maximum value. The remaining filter tap values are individually adaptively adjusted by the radio's control processor, which executes a tap adjustment routine to iteratively increment or decrement each variable tap value of the FIR filter to an 'optimized' value, that effectively minimizes the total (I and Q) power in the error in the data decisions performed by data signal analyzer.

Stepwise adaptive finite impulse response filter for spread spectrum radio

A data communications system (10) has a system management controller (100) and multiple data communications devices (21-1 through 21-n). The system management controller has a processor (110) and random access memory (115). The various data communications devices (21-1 through 21-n) are coupled to the system management controller (100) through a common address bus (12) and a common management bus (11). Through the processor (110), the system management controller (100) sequentially addresses each of the data communications devices (21-1 through 21-n) at a default data rate and determines a requested data rate for each device (FIG. 6, 305-333). The system management controller (100), through the processor (110), stores this requested data rate information, correlated with the address of each data communication device, in the random access memory (115) (FIG. 6, 305), and communicates with each such device at its requested data rate (FIG. 6, 335; FIG. 10, 500-545). In the event of errors, both the system management controller (100) and the addressed data communications device revert to a default data rate (FIG. 9, 435; FIG. 10, 525).

Apparatus and method for controlling and varying multiple data rates

Data communication stations 10, 12, 14 are connected by way of a shared bus 15 common to all the communication stations. When two stations attempt to access the shared bus simultaneously, a conflict resolution method if used to determine which of the two stations is allowed access to the bus 15. Each station seeking access to the bus 15 serially transmits its address. The priority of the stations is determined, and the station with priority is given access to the bus 15.

Contention resolution for a shared access bus

Growing community of inventors

Huntsville, AL, United States of America

Steven R Blackwell