Abstract: A method and apparatus of frame rate conversion where descriptive information relating to an input video signal is transmitted to the frame rate converter along with the input signal. The descriptive information is used to interpolate frames, allowing the interpolator to make pixel analysis using the descriptive information relating to the original signal. The descriptive information is derived by a compositor/scaler and is transmitted to the frame rate converter with the composited/scaled signal. There may be multiple input signals that are composited to make a final composited video output such as a picture-in-picture display. The information may be transmitted in-band with the video signal received by the frame rate converter. Alternatively, the descriptive information may be transmitted in a separate stream in a side-band manner. In another embodiment, the descriptive information may be transmitted to the frame rate converter separate from the video input source as commands or packets.

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).

Abstract: A method and system for performing response-time compensation on video pixel data includes an output coupled to a timing controller for, the timing controller providing response time pixel data to a video display screen or panel. The system including a video signal processing module to determine pixel data indicative of how to excite respective video pixels in a video frame. The system including an interface for outputting substantially concurrently, the current-frame pixel data relating to a pixel at a particular location in the current video frame and prior-frame pixel data relating to the pixel at the particular location in the prior video frame relative to the current video frame. The current-frame pixel data and the prior-frame pixel data can be interlaced in the output signal. The prior-frame pixel data can be compressed in the output signal. The output can include multiple channels and the current-frame pixel data and the prior-frame pixel data can be output over separate channels.

Abstract: An integrated circuit chip configured to be coupled to a single shared memory including, in combination, a memory access module, at least one video signal processing module, and a frame rate converter, wherein the memory access module is configured to coordinate access to the single shared memory by the at least one video signal processing module and the frame rate converter.

Abstract: A robust data extension, added to a standard 8VSB digital television signal, is used to improve the performance of a digital television receiver. Robust data packets are encoded at a 1/3-trellis rate as compared to normal data packets that are encoded at a 2/3-trellis rate. In addition to delivery of robust data for mobile applications, the redundant robust data packets also improve the performance of the receiver in the normal tier of service. In particular, the robust data packets improve the performance of the receiver equalizer filter in the presence of rapidly changing transient channel conditions such as dynamic multipath for both robust data packets and normal data packets. The robust data packets improve the performance of the carrier recovery loop and the symbol timing recovery loop. Backward compatibility with existing receivers is maintained for 1) 8VSB signaling, 2) trellis encoding and decoding, 3) Reed Solomon encoding and decoding, and 4) MPEG compatibility.

Abstract: An AGC circuit includes both wide-band and narrow-band VGAs. Two power monitors monitor the power level of the two VGAs. Based upon the signals provided by the power monitors, the AGC circuit derives two error terms. The AGC circuit filters and combines the error terms to determine a desired adjustment to the total gain and a desired adjustment to the distribution of the gain between the wide-band VGA and the narrow-band VGA. The AGC circuit also minimizes the noise figure of the narrow-band VGA subject to linearity constraints.

Abstract: Centrally controlled wireless networks require reliable communications between the central controller and each of the stations within the wireless networks. The structure of a wireless network is often dynamic, or ad-hoc, as stations enter and exit the network, or are physically relocated. The selection of the central controller for the network may also be dynamic, either because the current central controller desires to exit the network, or because the communication between the current central controller and one or more of the stations is poor. This invention discloses a method and apparatus for assessing the quality of the communication paths among all stations in the network. This assessment is useful as a continual monitor of the quality of the network, and can be utilized to select an alternative central control station based upon the quality of communication paths to and from this station. Additionally, the quality assessment can be utilized to establish relay communication paths, as required.

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.

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.

Abstract: An equalizer for use in a communication receiver includes an infinite impulse response (IIR) feedback filter operated in acquisition and tracking feedback modes on a sample by sample basis to form a hybrid Decision Feedback Equalizer (DFE) architecture. In acquisition mode, soft decision samples from the filtered received signal are input to the IIR filter. In the tracking mode, hard decision samples from a slicer are input to the IIR filter. Acquisition and tracking operating modes are selected in accordance with a set of decision rules on a sample by sample basis based on the quality of the current hard decision. If the current hard decision is low quality, then the soft decision sample (acquisition mode) is used. If the current hard decision is high quality, then the hard decision sample (tracking mode) is used. In such manner, the DFE is operated in a hybrid mode, i.e., using both soft and hard decisions on a sample by sample basis.

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.

Abstract: A multiple channel diversity receiver includes joint automatic gain control (AGC) signal processing wherein the first and second channels of the multiple channel diversity receiver share at least one joint AGC loop. The maximum difference between the AGC feedback signal in the control loop for the first channel and the AGC feedback control signal in the control loop for the second channel is limited to a selectable maximum differential. The AGC control loop with the stronger first RF signal thus limits the maximum amount that the weaker signal is amplified in the AGC control loop with the weaker second RF signal. By limiting the AGC feedback signal in the control loop of the second channel to a maximum differential with respect to the AGC feedback signal in the control loop of the first channel, the weaker signal is not overly amplified thereby avoiding the undue amplification of noise in the second channel.

Abstract: Original RF carriers are recovered for first and second channels in a diversity receiver and used to de-rotate (demodulate) each of the first and second received signals. The pilot loop filters of each channel are cross coupled to create a joint pilot loop between both channels. The channel with the stronger signal provides a dominant influence on the frequency of the synthesized recovered RF carrier in the channel with the weaker signal. The phase locked pilot loops in both channels will tend to be frequency locked to the frequency of the stronger signal, leaving the respective phase locked pilot loops to make an individual phase adjustment for each channel.

Abstract: First and second RF signals in the respective first and second channels of a multiple channel diversity receiver are processed jointly in a joint timing loop filter for baud clock recovery. The channel with the stronger signal determines the frequency of the baud clock for the channel with the weaker signal, leaving the respective PLL's to make individual phase adjustments for each channel. The first and second channels also share a skew corrector for baud clock recovery when the multipath delay between the first and second RF signals is greater than one whole baud clock period. The whole baud skew corrector computes the correlation between the first and second received signals, and if the correlation is low, shifts the first and second signals by one whole baud and recomputes the correlation. The process of shifting the first and second received signals and computing the correlation function is repeated for various whole baud shifts in accordance with a search strategy to find the best (highest) correlation.

Abstract: A slicer for a decision feedback error equalizer system that processes trellis encoded data using the ATSC trellis code is implemented in two parts. A first part includes a trellis decoder that estimates a single bit of the symbol. The second part includes two partial trellis decoders. A multiplexer directs the received digital samples to one of the two trellis decoders responsive to the estimated symbol. An alternative slicer estimates two bits of the output symbols and selects from among four decoders to fully decode the symbols. The slicer is used in an equalizer having adaptive filters that may operate either on passband or baseband signals. The slicer is used both to recover the carrier signal on which the symbols are modulated and to provide symbols to the second filter that are used to determine filter coefficients for the second filter.

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).

Abstract: Centrally controlled wireless networks require reliable communications between the central controller and each of the stations within the wireless networks. The structure of a wireless network is often dynamic, or ad-hoc, as stations enter and exit the network, or are physically relocated. The selection of the central controller for the network may also be dynamic, either because the current central controller desires to exit the network, or because the communication between the current central controller and one or more of the stations is poor. This invention discloses a method and apparatus for assessing the quality of the communication paths among all stations in the network. This assessment is useful as a continual monitor of the quality of the network, and can be utilized to select an alternative central control station based upon the quality of communication paths to and from this station. Additionally, the quality assessment can be utilized to establish relay communication paths, as required.

Abstract: An AGC circuit includes both wide-band and narrow-band VGAs. Two power monitors monitor the power level of the two VGAs. Based upon the signals provided by the power monitors, the AGC circuit derives two error terms. The AGC circuit filters and combines the error terms to determine a desired adjustment to the total gain and a desired adjustment to the distribution of the gain between the wide-band VGA and the narrow-band VGA. The AGC circuit also minimizes the noise figure of the narrow-band VGA subject to linearity constraints.

Abstract: A robust data extension added to a standard 8VSB digital television signal is used to improve the performance of a digital television receiver. The robust data extension is added to a standard 8VSB digital television transmission system by encoding high priority data packets in a rate ½ trellis encoder. The high priority data ½ trellis encoded packets are then multiplexed with normal data packets and input into the normal data service of an 8VSB system, which further contains a rate ⅔ trellis encoder. The combined trellis encoding results in a rate ⅓ trellis encoding for robust data packets and a rate ⅔ trellis encoding for normal packets. Backward compatibility with existing receivers is maintained for 1) 8VSB signaling, 2) trellis encoding and decoding, 3) Reed Solomon encoding and decoding, and 4) MPEG compatibility.

Abstract: The system transmits data between terminals of a wireless network. In the system, a base station/central controller (“BS/CC”) controls transmission of data from a transmitting terminal to plural receiving terminals, where the data is ordered in slots of a control data frame (“CDF”), and where each slot is reserved for a data transmission between the transmitting terminal and a specific receiving terminal. Specifically, the BS/CC divides the plural receiving terminals into a set of power-saving terminals and a set of non-power-saving terminals, and then reserves a set of slots in the CDF for data transmission between the transmitting terminal and the power-saving terminals, and another set of slots in the CDF for data transmission between the transmitting terminal and the non-power-saving terminals.