Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: In forming a current channel estimate from a received signal y, the received signal y is decoded to form data s, a convolution matrix ?is formed from a first portion of the data s, a matrix F1 is 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 F2 is 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 hpred is 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 ?, the matrices F1 and F2, the predicted channel estimate hpred, and a previous channel estimate h1.

Abstract: In forming a channel estimate, a received signal y is decoded to form data s, a convolution matrix ? is formed from the data s, a matrix F is formed from the data s such that the matrix F results from the forming of the matrix ? as a convolution matrix, and a conjugate gradient algorithm is performed to determine the channel estimate. The conjugate gradient algorithm is based on the received signal y, the matrix ?, and the matrix F.

Abstract: A received signal having a series of T-spaced symbols having more than two levels is sampled at a rate that produces successive samples SP, SC, and SN substantially equally spaced by T/2. An output representing the difference between the sign of the sample SN and the sign of the sample SP is generated, and the value of the sample SC is offset so that the value of the sample SC approaches zero. The offset value of the sample SC and the generated output are multiplied together in order to provide a timing error signal. The sampling of the received signal is controlled in accordance with the timing error signal.

Abstract: A received signal having a series of T-spaced symbols having more than two levels is sampled at a rate that produces successive samples SP, SC, and SN substantially equally spaced by T/2. An output representing the difference between the sign of the sample SN and the sign of the sample SP is generated, and the value of the sample Sc is offset so that the value of the sample SC approaches zero. The offset value of the sample Sc and the generated output are multiplied together in order to provide a timing error signal. The sampling of the received signal is controlled in accordance with the timing error signal.

Abstract: An MPEG encoded interlaced high definition video stream is decoded and down converted to lower resolution by an MPEG decoder with a reduced amount of reference picture memory. Received frame and field DCT coded blocks are down converted to reconstructed pixel field blocks by first converting the received frame DCT coded blocks to converted field DCT coded blocks. A vertical IDCT and a horizontal IDCT are then performed on the received field DCT coded blocks and on the converted field DCT coded blocks in order to produce residual and pixel field blocks as appropriate. The vertical IDCT is an N point vertical IDCT, and the horizontal IDCT is an M point horizontal IDCT, where N corresponds to the original block size, and where N>M. The residual and pixel field blocks are spatially filtered and down sampled vertically. IDCT, filtering, and down sampling operations are efficiently combined into single linear operators.

Abstract: An upper denture has an artificial teeth support base with side regions and a front region shaped for fitting onto a person's upper gums. The support base has an open area situated between the side regions and behind the front region and which exposes a portion of the roof of the wearer's mouth at that location. An arched center region of the support base extends between the side regions behind the open area and is shaped to fit against the roof of the mouth. The open configuration makes the denture more comfortable and provides a more natural environment in the mouth. For example, the tongue and foods and beverages may make direct contact with the top of the mouth. The support base may be articulated in a manner which enables adjustment of the fit of the denture after fabrication.

Abstract: In a reduced memory MPEG decoder, drift caused by the application of ½ pixel resolution motion vectors during prediction filtering is reduced. Received P and B frame and field DCT coded blocks are down converted. Reference pixels are selected based upon a received motion vector. The selected reference pixels are prediction filtered in order to produce a prediction output. If the motion vector is a ½ pixel resolution motion vector, a drift compensation value is added to the prediction output. Then, the prediction output is added to the down converted P and B frame and field DCT coded blocks in order to form lower resolution reconstructed pixel blocks.

Abstract: A downsampling apparatus converts a received DCT coefficient macroblock to a reconstructed pixel block and includes an IDCT module that performs an inverse DCT on the received DCT coefficient macroblock to produce a first intermediate block. A horizontal downsampler horizontally downsamples the first intermediate block to produce a second intermediate block. A calculation module calculates first and second errors. The first and second errors are calculated based upon a difference between the first intermediate block and first and second downsampled/upsampled versions of the first intermediate block derived from corresponding first and second vertical downsampling filters. A filtering module vertically downsamples the second intermediate block using the first or second vertical downsampling filter depending upon whether the first or second error is smaller. A motion compensator adds prediction reference pixels to the horizontally and vertically downsampled block, as appropriate, to form reconstructed pixels.