Zenith Electronics Corporation

Intersil Americas Inc.

Techwell, Inc.

Other

Zenith F. Ectronics LLC

Jin Hong Kim

Mark J Fimoff

Timothy G Laud

Scott M LoPresto

Serdar Ozen

Jinghua Jin

Lay Yee Lim

William J Hillery

Gregory Tomezak

Sreenivasa M Nerayanuru

Bruno Amizic

A novel framing method for a variable net bit rate digital communications system that utilizes a set of different QAM constellations and punctured trellis code combinations, each combination designated as a mode. This frame structure has a variable integral number of QAM symbols per frame depending on the selected mode, but the number of bytes and Reed-Solomon packets per frame is constant. This is achieved even though the number of data bits per QAM symbol for some modes is fractional. Also the number of trellis coder puncture pattern cycles per frame is an integer for all modes. This arrangement simplifies the synchronization of receiver processing blocks such as the Viterbi decoder, de-randomizer, byte de-interleaver, and Reed-Solomon decoder.

Frame structure for a QAM system

A method and system for determining a step size of an adaptive equalizer for a digital data receiver. The data received by the receiver includes coded symbols and uncoded symbols. The method includes determining a first error estimate based on decoded symbols corresponding to the coded symbols, determining a second error estimate based on the uncoded symbols, adaptively selecting the first error estimate or the second error estimate based on a convergence criterion, and determining a step size based on the selected error estimate.

Method for determining the step size for an LMS adaptive equalizer for 8VSB

A universal GPS traffic monitoring system that uses a plurality of GPS enabled mobile devices to transmit near real-time traffic direction and speed information to a server. The sever processes the information thereby reducing the computational load and power consumption of the mobile devices. The system uses a Traffic Pattern Recognition software program that recognizes only valid traffic data while filtering out unwanted traffic data. The system creates a Distributed Traffic Data Store database containing the average speeds for designated traffic monitoring points (TMPs) created for the region. A request for traffic data containing the boundary data and the zoom level is sent from the mobile device to the server. The server reviews the request and determines which specific Distributed Traffic Data Store database contains the information and then creates and sends a compressed file containing the traffic information relevant to the TMPs in the request to the mobile device.

Universal GPS traffic monitoring system

A decision feedback equalizer is operated by making first symbol decisions from an output of the decision feedback equalizer such that the first symbol decisions are characterized by a relatively long processing delay, by making second symbol decisions from the output of the decision feedback equalizer such that the second symbol decisions are characterized by a relatively short processing delay, and by determining tap weights for the decision feedback equalizer based on the first and second symbol decisions. The first symbol decisions may be derived from the output of a long traceback trellis decoder. The second symbol decisions may be derived either from the output of a short traceback trellis decoder or from shorter delay outputs of the long traceback trellis decoder.

Channel impulse response estimating decision feedback equalizer

Novel systems and methods are described in which performance of equalizers can be improved by reducing the effects of error propagation in equalizers that use a Viterbi Decoder. Systems and methods of symbol correction in prediction decision feedback equalization architectures are described including systems and methods that include an enhanced Viterbi decoder and novel methods of symbol correction to obtain better system performance. The use of a blending algorithm is described to reduce errors in symbol decoding. Histories of deep trace back depth symbols can be maintained to enable more accurate decisions. Systems and methods described can provide advantage in the feedback path of adaptive equalizers in trellis decoders. The invention provides novel techniques for improving the performance of equalizers by reducing the effects of error propagation in equalizers that use a Viterbi Decoder.

Reducing equalizer error propagation with a low complexity soft output viterbi decoder

Program clock references in first and second MPEG data streams are re-stamped in accordance with delays introduced into the first and second MPEG data streams. Accordingly, the program clock references in the first MPEG data stream are re-stamped according to a variable delay in the first MPEG data stream, and the program clock references in the second MPEG data stream are re-stamped according to a variable delay in the second MPEG data stream. The re-stamped program clock references in the second MPEG data stream are corrected according to a fixed delay in the second MPEG data stream. The first and second MPEG data streams are multiplexed, and the multiplexed first and second MPEG data streams are transmitted and received.

PCR jitter reduction in a VSB and/or EVSB multiplexer system

The present invention provides a novel technique for improving the performance of equalizers by reducing the effects of error propagation in equalizers that use a Viterbi Decoder. Methods and systems are described that can improve the performance of equalizers by reducing the effects of error propagation in equalizers that use a Viterbi Decoder. Systems and methods of symbol correction in prediction decision feedback equalization ('pDFE') architectures are described. Systems are described that include one or more enhanced Viterbi decoders together with novel methods of symbol correction to obtain better system performance. Systems and methods are described that utilize dual pDFEs and can use a blending algorithm to reduce errors in symbol decoding. Dual pDFEs are described that include forward and backward Viterbi decoders wherein the backward Viterbi decoded may operate on time reversed data blocks and with some degree of latency. Forward and backward Viterbi decoders can generate different decoded symbols from the same equalized data. A blending algorithm is described for weighting results based on reliability of the respective decoded symbols. A forward-backward blender can additionally increase performance of the second pDFE by blending long delayed trellis symbols from the first Viterbi decoder with symbols output by the second Viterbi decoder.

Dual PDFE system with forward-backward Viterbi

Dual pDFE system with forward-backward viterbi

Reducing equalizer error propagation with a low complexity soft output Viterbi decoder

A method and system for channel tracking in an adaptive equalizer for a digital data receiver. The method includes determining a first set of tap weights and a second set of tap weights of the equalizer, and determining a difference between the first and second sets of tap weights. The method also includes determining an error estimate based on symbols received at the receiver, comparing the error estimate with a divergence threshold, and determining a step size factor based on the difference and the comparison.

Method for channel tracking in an LMS adaptive equalizer for 8VSB

In forming a current channel estimate from a received signal y, the received signal y is decoded to form data s, a convolution matrix &#x15c;is formed from a first portion of the data s, a matrix Fis formed from a second portion the data s such that the second portion of the data s includes data that is less recent that the data in the first portion of the data s, a matrix Fis formed from a third portion the data s such that the third portion of the data s includes data that is more recent than the data in the first portion of the data s, a predicted channel estimate his determined, and a conjugate gradient algorithm is performed to determine the current channel estimate. The conjugate gradient algorithm is based on the received signal y, the matrix &#x15c;, the matrices Fand F, the predicted channel estimate h, and a previous channel estimate h.

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Lake Zurich, IL, United States of America

Jin Hong Kim