Patents by Inventor Raul A. Casas

Raul A. Casas has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20070183452
    Abstract: An apparatus, configured to receive from a receiver a multiplexed data stream of multiplexed video data packets, the multiplexed data stream being produced from multiple input video streams received by the receiver. The apparatus includes a point-of-deployment (POD) module controller configured to use a POD module to decrypt the multiplexed data stream and a demultiplexor connected to the decryption module and configured to demultiplex the multiplexed data stream such that the video data packets are grouped in respective output video data streams, the demultiplexor being further configured to use timing information associated with the multiplexed data stream such that packets in the output video data streams have time spacings in accordance with the timing information.
    Type: Application
    Filed: February 3, 2006
    Publication date: August 9, 2007
    Inventors: Mark Hryszko, Raul Casas, Samir Hulyalkar
  • Publication number: 20060215746
    Abstract: A digital filter pre-calculates C(1)*S(n?1), C(2)*S(n?2) . . . C(p?1)*S(n?p+1), prior to the arrival of sample S(n). As such y ? ( n ) = ? k = 0 k = p - 1 ? C ? ( k ) * S ? ( n - k ) may be calculated as a result of a single further multiply and accumulate operation, upon arrival of the symbol S(n). This, significantly reduces the latency of the filter.
    Type: Application
    Filed: March 25, 2005
    Publication date: September 28, 2006
    Applicant: ATI Technologies Inc.
    Inventors: Raghuram Behara, Thomas Meyer, Yiwen Yu, Ajay Bhaskaran, Raul Casas
  • Patent number: 7031405
    Abstract: Carrier phase recovery employs a single-axis blind cost criterion from the Bussgang class of functions, and its stochastic gradient, to generate a carrier phase error used to adjust a received and demodulated signal to near baseband. For one implementation, the estimate is derived in accordance with a Single-Axis Constant Modulus (SA-CM) criterion and its stochastic gradient via a SA-CM algorithm (SA-CMA). The carrier phase error is then used to adjust the carrier frequency and phase of the received and demodulated signal toward the frequency and phase of the carrier used to modulate the transmitted symbols, driving the carrier phase error to zero. The values used for the phase recovery may be either i) an IIR filtered signal, ii) a processed signal (e.g., decisions for the signal symbols), or iii) an equalized and processed signal.
    Type: Grant
    Filed: August 3, 2001
    Date of Patent: April 18, 2006
    Assignee: ATI Research, Inc.
    Inventors: Azzedine Touzni, Raúl A. Casas, Thomas J. Endres, Stephen L. Biracree, Christopher H. Strolle, Samir N. Hulyalkar
  • Patent number: 7027500
    Abstract: A single-axis receiver processing, for example, complex vestigial sideband modulated signals with an equalizer with forward and feedback filters. Forward and feedback filters have parameters that are initialized and adapted to steady state operation. Adaptive equalization employs linear predictive filtering and error term generation based on various cost criteria. Adaptive equalization includes recursive update of parameters for forward and feedback filtering as operation changes between linear and decision-feedback equalization of either single or multi-channel signals. An adaptive, linear predictive filter generates real-valued parameters that are employed to set the parameters of the feedback filter. In an initialization mode, filter parameters are set via a linear prediction filter to approximate the inverse of the channel's impulse/frequency response and a constant modulus error term for adaptation of the filter parameters.
    Type: Grant
    Filed: December 11, 2001
    Date of Patent: April 11, 2006
    Assignee: ATI Research, Inc.
    Inventors: Raúl A. Casas, Azzédine Touzni, Thomas J. Endres, Stephen L. Biracree, Christopher H. Strolle, Samir N. Hulyalkar
  • Patent number: 6985549
    Abstract: Symbol timing recovery employs a blind cost criterion from the Bussgang class of functions, and its stochastic gradient, to generate a timing phase error used to adjust sampling of received symbols. For one implementation, the estimate is derived in accordance with the Constant Modulus (CM) criterion and its gradient via the CM algorithm (CMA), and the estimate is calculated from a sequence of samples. This estimate is then used to adjust the period and phase of the sample sequence toward the period and phase of the transmitted symbols, driving the timing phase error to zero. The values used may be either i) samples themselves, ii) processed (e.g., interpolated) samples, or iii) equalized and processed samples. In addition, timing phase error estimates for other cost criteria, including the least mean squares algorithm, may be generated. These timing phase error estimates are selected either alone or in combination for deriving the timing phase error used to adjust the period and phase of the sample sequence.
    Type: Grant
    Filed: January 17, 2001
    Date of Patent: January 10, 2006
    Assignee: ATI Research, Inc.
    Inventors: Stephen L. Biracree, Azzedine Touzni, Thomas J. Endres, Christopher H. Strolle, Samir N. Hulyalkar, Raúl A. Casas
  • Publication number: 20050212977
    Abstract: An audio/video separator provides a high-performance and cost-effective solution to analog TV reception with only one A/D converter and a minimum of analog IF components. The apparatus may operate on a digitized TV signal and, when integrated with a digital video processor, process video signals while separating audio signals. The resultant audio and video signals may be considered to have excellent signal quality due to highly optimized demodulation architecture and digital signal processing techniques on both audio and video data paths.
    Type: Application
    Filed: March 29, 2004
    Publication date: September 29, 2005
    Applicant: ATI Technologies Inc.
    Inventors: Daniel Zhu, Hulyalkar Samir, Binning Chen, Raul Casas, Dongsheng Wu
  • Publication number: 20050157820
    Abstract: A digital receiver, that may be used to receive VSB/QAM digital television signals, includes an adaptive fine carrier recovery circuit that compensates for deviations in the carrier frequency or phase. The carrier recovery circuit de-rotates a signal including phase errors. Estimations of phase errors are filtered using a filter whose gain and bandwidth are adjusted adaptively. This allows the carrier recovery circuit to track phase/frequency offset without introducing significant jitter. In one embodiment, the receiver includes a DFE, and the adaptive carrier recovery circuit mitigates instability that might be associated with the DFE.
    Type: Application
    Filed: January 15, 2004
    Publication date: July 21, 2005
    Inventors: Supat Wongwirawat, Azzedine Touzni, Mark Hryszko, Raul Casas, Yiwen Yu
  • Publication number: 20040248517
    Abstract: A method for selecting an antenna direction setting for optimum signal reception prior to channel equalization provides a set of metrics, referred to as channel quality metrics (CQM), that characterize the quality of the received signal for a given antenna setting and a generic algorithm that uses these metrics to select the antenna setting for an optimum reception. This invention utilizes five main CQMs: a Signal Strength Metric (SSM), a minimum mean squared error of a decision feedback equalizer (MMSE (DFE)) channel quality metric, a MMSE for a linear equalizer (MMSE(LE)) channel quality metric, a Spectral Flatness Metric (SFM) and an interference degradation metric (IDM).
    Type: Application
    Filed: September 15, 2003
    Publication date: December 9, 2004
    Inventors: Samuel H. Reichgott, Raul A. Casas, Samir N. Hulyalkar, Azzedine Touzni, John J. Zygmaniak, Andrew E. Youtz
  • Patent number: 6668014
    Abstract: A digital communication receiver includes a blind equalizer using the Constant Modulus Algorithm (CMA) to compensate for channel transmission distortion in digital communication systems. Improved CMA performance is obtained by using a partial trellis decoder to predict 1 bit or 2 bits of the corresponding 3-bit transmitted symbol. The predicted bits from the partial trellis decoder are used to reduce the effective number of symbols in the source alphabet, which reduces steady state jitter of the CMA algorithm. Specifically, the received input signal to the CMA error calculation is shifted up or down by a computed delta (&Dgr;), in accordance with the predicted bit(s). In addition, a different constant gamma (&ggr;), for the CMA error calculation is selected in accordance with the predicted bit(s).
    Type: Grant
    Filed: December 9, 1999
    Date of Patent: December 23, 2003
    Assignee: ATI Technologies Inc.
    Inventors: Thomas J Endres, Samir N Hulyalkar, Christopher H Strolle, Troy A Schaffer, Raul A Casas, Stephen L Biracree, Anand M Shah