| Techwell, Inc. Patent applications |
| Patent application number | Title | Published |
|---|
| 20100266007 | DUAL PDFE SYSTEM WITH FORWARD-BACKWARD VITERBI - 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. | 10-21-2010 |
| 20100260267 | REDUCING EQUALIZER ERROR PROPAGATION WITH A LOW COMPLEXITY SOFT OUTPUT VITERBI DECODER - 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. | 10-14-2010 |
| 20100194899 | MIXED FORMAT MEDIA TRANSMISSION SYSTEMS AND METHODS - Systems and methods for operating cameras are described. An image signal received from an image sensor can be processed as a plurality of video signals representative of the image signal. An encoder may combine baseband and digital video signals in an output signal for transmission over a cable. The video signals may include substantially isochronous baseband and digital video signals. The baseband video signal can comprise a standard definition analog video signal and the digital video signal may be modulated before combining with the baseband video signal and/or transmitting wirelessly. The digital video signal may be a compressed high definition digital video signal. A decoder demodulates an upstream signal to obtain a control signal for controlling the position and orientation of the camera and content of the baseband and digital video signals. | 08-05-2010 |
| 20090190643 | CARRIER PHASE INDEPENDENT SYMBOL TIMING RECOVERY METHODS FOR VSB RECEIVERS - The present invention provides a novel symbol timing recovery method for VSB receivers. Systems are described that comprise a timing error detector (TED) that produces an exact symbol timing error even in the presence residual carrier phase offset, loop filter that controls the characteristics of acquisition and tracking of digital PLL loop, Voltage/Numerically Controlled Oscillator (VCO/NCO) that adjusts the sampling instant and phase, A/D converter that samples a continuous VSB input signal, and a interpolating squared root raised cosine filter that performs both matched filtering and a compensation of constant timing offset of quarter symbol caused by the invented TED. The timing error detector in this invention comprises an envelope detector, band pass filter, squaring block, high pass filter, and decimator. It uses both in-phase and quadrature-phase component of received VSB signal, is operated at twice of a symbol frequency F, and guarantees consistent symbol timing error signal resulting in the improvement of receiver's performance. | 07-30-2009 |
