Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, a graphics input and an audio input simultaneously. The system may use anti-aliased text and graphics to provide high quality display of graphical elements, or glyphs, which represent an image of a character of text or graphics, on television and other displays. The graphical elements may be superimposed over live video or arbitrary graphics imagery.

Abstract: In a communications receiver for quadrature demodulation, a feedback technique for reducing the image response of the receiver. The communications receiver includes an I demodulator and a Q demodulator. A local oscillator (LO) signal is provided by a PLL to a quadrature LO generator that provides an LO_I signal to an I demodulator and an LO_Q signal to a Q demodulator. The LO_I and LO_Q signals are amplitude and phase-controlled versions of the LO signal. An image/signal ratio (I/S) detector detects the relative phase difference and the relative amplitude difference between the respective output terminals of the I demodulator and the Q demodulator and applies an amplitude control signal and a phase control signal to corresponding amplitude control and phase control inputs of the quadrature LO generator. The I/S detector calibrates the quadrature LO generator during the interstitial interval between the reception of data packets.

Abstract: A Variable Gain Amplifier (VGA) amplifies an input signal according to a gain, to produce an amplified signal. A detector module detects a power indicative of a power of the amplified signal. A comparator module compares the detected power to a high threshold, a low threshold and a target threshold intermediate the high and low thresholds. A controller module changes the gain of the VGA so as to drive the detected power in a direction toward the middle threshold when the comparator module indicates the detected power is not between the high and low thresholds.

Abstract: A radio frequency circuit includes a first differential RF path and a second differential path. The first differential RF path includes at least one RF block that includes a first differential section and a second differential section, wherein the first differential section is symmetrical with the second differential section. The second differential RF path includes at least one RF block that includes a first differential section and a second differential section, wherein the first differential section is symmetrical with the second differential section. The first and second half differential sections of the at least one RF block of the first differential RF path are symmetrically placed on at least one layer around the first and second half differential sections of the at least one RF block of the second differential RF path, wherein the first and second half differential sections of the at least one RF block of the second differential RF path are fabricated on the at least one layer.

Abstract: Variable modulation within combined LDPC (Low Density Parity Check) coding and modulation coding systems. A novel approach is presented for variable modulation encoding of LDPC coded symbols. In addition, LDPC encoding, that generates an LDPC variable code rate signal, may also be performed as well. The encoding can generate an LDPC variable code rate and/or modulation signal whose code rate and/or modulation may vary as frequently as on a symbol by symbol basis. Some embodiments employ a common constellation shape for all of the symbols of the signal sequence, yet individual symbols may be mapped according different mappings of the commonly shaped constellation; such an embodiment may be viewed as generating a LDPC variable mapped signal. In general, any one or more of the code rate, constellation shape, or mapping of the individual symbols of a signal sequence may vary as frequently as on a symbol by symbol basis.

Abstract: Methods, systems, and apparatuses for attaching heat sinks to integrated circuit packages using thermally conductive adhesive materials are described. The adhesive materials can be shaped to conform to surfaces of the integrated circuit package and/or heat sink, prior to hardening, such as by curing the adhesive material.

Abstract: A low-complexity sampling rate conversion (SRC) method and apparatus for the processing of digital audio signals. A first stage upsamples an input audio signal to generate an upsampled audio signal. For example, the first stage may perform 1:2 upsampling using a halfband filter. A second stage re-samples the upsampled audio signal from the first stage at a target sampling rate. For example, re-sampling may be achieved using linear interpolation.

Abstract: A transmitter generates a transmitter output signal from first and second baseband signals. The transmitter includes a detector to detect a local oscillator (LO) leakage signal in the transmitter output signal. A controller coupled to the detector determines a direct LO coupling component and a baseband DC offset component of the LO leakage signal. First and second variable current sources are adjusted by the controller to provide first and second DC offsets to the first and second baseband signals, respectively. The first and second DC offsets reduce the direct LO coupling component. Third and fourth variable current sources are subsequently adjusted by the controller to provide third and fourth DC offsets to the first and second baseband signals, respectively. The third and fourth DC offsets reduce the baseband DC component. Overall, reducing the direct LO coupling component and the baseband DC component reduces a power of the LO leakage signal.

Abstract: Characterizing channel response in a single upstream burst using redundant information from training tones (TTs). The invention is operable to utilize inserted TTs, contained within a transmitted data frame, to provide for an improved estimate of a communication channel's actual response and an improved estimate of the noise of the communication channel. The invention determines a maximum allowable delay spread of the many communication paths within a multi-path communication channel. Using the redundant TTs information then a portion of the finite impulse response of the communication channel, within the time domain, may be zeroed, thereby providing a much improved channel estimate and noise estimate. Using the redundant TTs, less noise is introduced onto the data tones (DTs) within a data frame. The present invention is also able to identify those portions of the TTs that are attributable to the actual channel and those that are attributable to the channel's noise.

Abstract: Single stage implementation of min*, max*, min and/or max to perform state metric calculation in soft-in soft-out (SISO) decoder. This allows for calculation of state metrics in an extremely efficient, fast manner. When performing min or max calculations, comparisons are made using 2 element combinations of the available inputs. Subsequently, logic circuitry employs the results of the 2 element comparisons the smallest (min) or largest (max) input. The max or min implementations may be employed as part of the max* and/or min* implementations. For max* and/or min* implementations, simultaneous calculation of appropriate values is performed while determining which input is the smallest or largest. Thereafter, the determination of which input is the smallest or largest is used to select the appropriate resultant value (of the values calculated) for max* and/or min*. Various degrees of precision are employed for the log correction values within the max* and/or min* implementations.

Abstract: The present invention relates to frequency dividers. The frequency divider comprises an input, a counter, a first comparator, an interconnect, and an output. The counter has a counter reset port and is configured to receive a clock signal from the input and to produce a sum signal. The first comparator is configured to receive the sum signal, to compare the sum signal to a first integer, and to produce a first comparison signal. The interconnect is configured to convey the first comparison signal from the first comparator to the counter reset port. The output coupled to the first comparator. The clock signal has a periodic waveform. The sum signal represents a first sum, which equals a number of waveforms of the clock signal received by the counter after the counter has been reset. In a first embodiment, the first integer is selectable from a set of at least three consecutive integers. In a second embodiment, a frequency of the clock signal is at least 1.5 gigahertz.

Abstract: Modified branch metrics for processing bit-soft decisions to account for phase noise impact on cluster variance (CV). The present invention is able to partition a modulation scheme's constellation into two or more regions, so that the bit-soft decision branch metrics may be adjusted based on the CV of the various constellation points. A confidence level may be attached to the various constellation points based on their particular CVs. There are a number of methods to ascertain the CV of the constellation's points, including finding characteristics of various components in a communication system (transmitter, communication channel and receiver), and any method may be used within various embodiments. The modification of the branch metrics/confidence level may be performed in a communication receiver; the communication receiver may be implemented in a communication system employing the vector orthogonal frequency division multiplexing (VOFDM) portion of the broadband wireless internet forum (BWIF).

Abstract: A switching regulator automatically operates in pulse width modulation (“PWM”) mode for high load currents and in burst mode for low load currents. The switching regulator includes a pair of switches to provide a regulated current to a load. The switching regulator further includes a multi-input comparator. A first input of the comparator is coupled to an output of the pair of switches. A second input of the comparator is coupled to a filtered version of the output and a third input is coupled to a reference waveform. The first, second and third inputs of the comparator form a combined input signal to the comparator. An output signal of the comparator is generated by comparing the combined input signal to a threshold of the comparator. The output signal determines a switching frequency of the pair of switches such that the switching frequency is automatically reduced when the load is decreased.

Abstract: A one-time programmable device includes a controller, a protection system, a static storage element and a latch, which can be referred to as a latch-based one-time programmable (OTP) element. In one example, the static storage element includes a thin gate-oxide that acts as a resistance element, which, depending on whether its blown, sets the latch into one of two states.

Abstract: A signal processing system which discriminates between voice signals and data signals modulated by a voiceband carrier. The signal processing system includes a voice exchange, a data exchange and a call discriminator. The voice exchange is capable of exchanging voice signals between a switched circuit network and a packet based network. The signal processing system also includes a data exchange capable of exchanging data signals modulated by a voiceband carrier on the switched circuit network with unmodulated data signal packets on the packet based network. The data exchange is performed by demodulating data signals from the switched circuit network for transmission on the packet based network, and modulating data signal packets from the packet based network for transmission on the switched circuit network. The call discriminator is used to selectively enable the voice exchange and data exchange.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions multi-transmitter system for unshielded twisted pair (UTP) data communication applications. For each transmitter, digital transmit data is converted to a current-mode differential signal analog waveform by a digital-to-analog converter (DAC). The output current from each DAC is used to generate the required transmit voltage on the respective UTP line. Timing circuitry staggers the time base of each transmitter to reduce the aggregate EMI emissions of the multi-transmitter system.

Abstract: The present invention includes an optical transceiver having a fiber module with an optical data input and an electrical data output. The fiber module further includes a signal detect output that indicates the receipt of valid optical data. A physical layer device having a receive input is coupled to the electrical data output through a switch that is controlled by the signal detect output. The switch passes electrical data from the electrical data output of the fiber module to the receive input when the signal detect output indicates the receipt of valid optical data, and does not pass the electrical data when the signal detect output indicates invalid optical data. By using this configuration, the signal detects pins of the physical layer device are eliminated. In another embodiment, the switch is not utilized, and the electrical data output of the transceiver is ac-coupled to the differential receive input of the physical layer device.

Abstract: A low-complexity sampling rate conversion (SRC) method and apparatus for the processing of digital audio signals. A first stage upsamples an input audio signal to generate an upsampled audio signal. For example, the first stage may perform 1:2 upsampling using a halfband filter. A second stage re-samples the upsampled audio signal from the first stage at a target sampling rate. For example, re-sampling may be achieved using linear interpolation.

Abstract: A radio frequency transmitter includes a digital baseband and coding module, an inverse fast Fourier transform (IFFT) module, a complex digital filter, a complex digital-to-analog converter and a radio frequency modulation module. The digital baseband and coding module is operably coupled to convert outbound data into outbound symbols in accordance with a baseband encoding protocol. The IFFT module is operably coupled to convert the outbound symbols into a complex time domain sample sequence. The complex digital filter is operably coupled to filter the complex time domain sequence such that signal strength of outbound RF signals in an exclusion RF band is at or below a specified signal strength with negligible attenuation on in-band signal strength.

Abstract: Methods and systems for reconfigurable soft-output bit demapping, reconfigurable for different modes of operation (i.e., different transmitter/receiver configurations) and for different modulation schemes are provided. In an embodiment, a reconfigurable soft-output bit demapping system includes a mode/modulation independent equalizer, a plurality of mode/modulation independent soft-slicers coupled to the outputs of the equalizer, a plurality of mode/modulation independent post-scalers coupled to the outputs of the soft-slicers, and a mode-dependent coefficient calculator. The coefficient calculator generates parameters for configuring the equalizer, the soft-slicers, and the post-scalers according to the used mode of operation and modulation scheme.