Abstract: A receiver, implemented with low noise and low distortion, to process an input signal containing signals of interest and unwanted interference signal. In an embodiment, the receiver contains a mixer which generates an intermediate signal in the form of an electric current, and a filter which filters the unwanted interference signals from the intermediate signal. The intermediate signal is centered around a lower frequency compared to a carrier frequency of the input signal. Due to the current mode interface between the mixer and the filter circuit, low noise and low distortion may be attained.

Abstract: A system and method to measure the clock skew between transmitting and receiving devices operating with independent clock sources over a packet network is described. To provide adaptive playout in an IP telephony device without a sequencing scheme in the packets, the clock skew is measured and recorded. Using a PCM resampler that is implemented with an interpolation filter bank of FIR subfilters, the change in depth of the playout buffer during transmission is analyzed, and this change infers the clock rate associated with the transmission.

Abstract: Systems and methods are provided for switching between power supply rail voltages for a differential driver device of a class G amplifier device. The amplifier device employs power MOSFETs to switch between supplying high supply voltages and low supply voltages to the power rails of the differential driver. The class G amplifier can be employed in driving an ADSL signal over a telephone line. A control device ramps the power supply rail voltage between low power supply states and high power supply states to mitigate noise and spikes that can be coupled to the output signal.

Abstract: A hybrid digital and analog phase locked loop. A voltage controlled oscillator is provided, having a fine tune input, a coarse tune input and an output. A frequency divider has an input connected to receive a signal provided by the output of the voltage controlled oscillator, and has an output for providing a signal having a frequency that is divided with respect to a signal provided to its input. A phase detector is connected to receive a reference input signal having a reference frequency at a first input thereof and is connected to receive the signal provided by the output of the frequency divider. The phase detector has an output for providing a phase error signal. An analog is circuit configured as a proportional filter and is connected to receive the phase error signal and to provide a fine tune signal at the fine tune input of the voltage controlled oscillator.

Abstract: A method of communicating speech across a communication link using very low digital data bandwidth is disclosed, having the steps of: translating speech into text at a source terminal; communicating the text across the communication link to a destination terminal; and translating the text into reproduced speech at the destination terminal. In a preferred embodiment, a speech profile corresponding to the speaker is used to reproduce the speech at the destination terminal so that the reproduced speech more closely approximates the original speech of the speaker. A default voice profile is used to recreate speech when a user profile is unavailable. User specific profiles can be created during training prior to communication or can be created during communication from actual speech. The user profiles can be updated to improve accuracy of recognition and to enhance reproduction of speech. The updated user profiles are transmitted to the destination terminals as needed.

Abstract: An apparatus, system and method for clamping a video signal input to a coupling capacitor (215) for providing a clamping voltage. A charging current is applied to the capacitor (215) via an amplifier (225) having a first input (227) coupled with the capacitor output and a second input (226) coupled to a reference potential, the amplifier (225) is responsive to the capacitor output signal and the reference potential for providing the charging current to the capacitor (215). The current has a linearly varying magnitude which is proportional to a difference between the capacitor output and the reference potential.

Abstract: A system to enable TTY communication between a legacy TTY phone and an IP phone over a packet network using a TTY relay protocol established between the IP phone and a media gateway at a central office of the PSTN. The system may also use a voice over Internet Protocol gateway to connect a personal computer to the packet network instead of an IP phone to accomplish TTY communication between software on the computer and a legacy TTY phone.

Abstract: A computer implemented method accesses data in a look up table via an index divided into a coarse index and a fine index. The method calculates the coarse index and fetches plural look up table entries. While the fetch is in progress, the method calculates the fine index. The method determines and extracts the look up table entry corresponding to the combined coarse and fine indexes Fetching plural look up table entries includes executing a single word load instruction, a doubleword load instruction or a pair of sequential or simultaneous single word load instructions. Extracting the look up table entry may include a section select move instruction, an extract and zero-extend bit field instruction or a shift and mask operation.

Abstract: A bootstrapping circuit capable of sampling inputs beyond a supply voltage which includes a bootstrapped switch coupled between an input node and an output node, a first transistor having a first end coupled to a control node of the bootstrapped switch, a first capacitor having a first end coupled to a second end of the first transistor, a second transistor coupled between the first end of the first transistor and a supply node, and having a control node coupled to a first clock signal node, a third transistor coupled between the second end of the first transistor and the supply node, a charge pump having an output coupled to a control node of the third transistor, a level shifter having an output coupled to a second end of the first capacitor, a fourth transistor cross-coupled with, the first transistor, a fifth transistor having a second end coupled to the first end of the fourth transistor, and having a control node coupled to the output of the level shifter, and a sixth transistor coupled between the firs

Abstract: A system for reducing noise in an acoustical signal comprises a sampler (104) for obtaining discrete samples of the acoustical signal, an analog to digital converter (106), and a noise suppression circuit (108). The noise suppression circuit (108) selects a fixed number of samples. These samples are multiplied by a windowing function and the fast Fourier transform is computed to yield transformed windowed signals. A smoothed power estimate and a noise estimate are calculated. The noise estimate and the smoothed power estimate is used to calculate a gain function. A transformed speech signal is obtained by multiplying the gain function with the transformed windowed signal. Then, the inversed fast Fourier transform of the transformed speech signal is added to a portion of the speech signal of a previous frame.

Abstract: A loss-of-signal (LOS) detector includes a variable gain amplifier with an input receiving an input signal, a threshold comparator with a first input receiving a signal derived from an output of the variable gain amplifier, a second input receiving a reference level and an output providing a loss-of-signal indication signal. The variable gain amplifier has a gain control input receiving a gain control signal derived from the output of the threshold comparator and such that the gain of the variable gain amplifier is set to a lower value when the loss-of-signal indication signal is active, and set to a higher value when the loss-of-signal indication signal is not active. Accordingly, the LOS detector needs only one decision level for both of the LOS and NotLOS decisions, which is set in the linear range of the signal detector so that the hysteresis is reproduced precisely.

Abstract: Ensuring sufficient bias current is provided to a portion of a circuit containing low voltage transistors operating with a high supply voltage. Such a sufficient bias current may be ensured by generating a primary bias current from a low supply voltage and a backup bias current from a high supply voltage, and providing the backup bias current as the bias current if the primary bias current is not present. The primary bias current may be provided as the bias current when the low supply voltage is available. Thus, the backup bias current is provided as bias current in case of undesirable supply sequencing.

Abstract: Linking addressable shadow port (LASP) and protocol allows addressing the LASP and configuring the connection of multiple Secondary Test Access Ports (TAPs) of the LASP using a single protocol or protocol bypass inputs. Multiple LASPs are cascaded and the connection of their secondary TAPs are configured using the LASP protocol or protocol bypass inputs.

Abstract: The present invention facilitates semiconductor fabrication by providing methods of fabrication that selectively form high-k dielectric layers within NMOS regions. An I/O dielectric layer is formed in core and I/O regions of a semiconductor device (506). The I/O dielectric layer is removed (508) from the core region of the device. A core dielectric layer is formed in the core region (510). A barrier layer is deposited and patterned to expose the NMOS devices of the core region (512). The core dielectric layer is removed from the core NMOS devices (514). A high-k dielectric layer is formed (514) over the core and I/O regions. Then, the high-k dielectric layer is removed (512) from PMOS regions/devices of the core region and the NMOS and PMOS regions/devices of the I/O region.

Abstract: The invention relates to a software system and method for automatically verifying the correct execution of an application ported from one instruction set architecture (ISA) to another ISA. In this method, versions of the application are prepared for the two ISAs. Each version is then executed in a simulator or emulator for the appropriate ISA and the results of any change in memory made during the execution are compared. If each memory change made during the execution of the target version of the application is found to be equivalent to a memory change made during the execution of the source version of the application, the execution of the target (or ported) application is verifiably correct.

Abstract: A method for measuring noise parameters includes generating a noise signal at a noise source. The noise signal includes a first input signal at a first frequency and a second input signal at a second frequency. The first input signal and the second input signal are modulated onto a carrier to generate a modulated signal. The modulated signal is attenuated to a desired power level and applied to a device under test to obtain a noise measurement.

Abstract: A digital sigma-delta modulator requiring minimal die area and dissipating minimal power is formed with a plurality of integration stages coupled in tandem between an input node and an output node. The bit width of signals in the integration stages is progressively reduced from the first to the last integration stage without compromising modulator accuracy. A quantizer between the last integration stage and the output node provides the final reduction of signal bit width. The gain of the modulator feedforward and feedback paths are integer powers of two to further simplify the digital computation. In an exemplary implementation, three integration stages to form a third-order modulator are coupled in tandem between the input node and the output node. The gains of feedback and feedforward paths in one preferred embodiment are unity, and in some embodiments, one feedforward path has gain of 0.5.

Abstract: The uplink data rate is dynamically adjusted in a mobile station according to the mobile station's ability to meet QoS (quality of service) requirements of applications executing on the mobile station. In an embodiment, the transition probabilities received from a mobile network are first compensated according to the ability to meet QoS requirements, and the uplink data rate is then computed based on the compensated transition probabilities. According to another aspect of the present invention, the base station dynamically adjusts the transition probabilities based on delay bound requirement of packets and/or average delay or data flow rate requirement.

Abstract: A system for, and method of, creating generalized tied-mixture hidden Markov models (HMMs) for noisy automatic speech recognition. In one embodiment, the system includes: (1) an HMM estimator and state tyer configured to perform HMM parameter estimation and state-tying with respect to word transcriptions and a pronunciation dictionary to yield continuous-density HMMs and (2) a mixture tyer associated with the HMM estimator and state tyer and configured to tie Gaussian mixture components across states of the continuous-density HMMs and a phone confusion matrix thereby to yield the generalized tied-mixture HMMs.

Abstract: A system for, and method of, noisy automatic speech recognition employing joint compensation of additive and convolutive distortions and a digital signal processor incorporating the system or the method. In one embodiment, the system includes: (1) an additive distortion factor estimator configured to estimate an additive distortion factor, (2) an acoustic model compensator coupled to the additive distortion factor estimator and configured to use estimates of a convolutive distortion factor and the additive distortion factor to compensate acoustic models and recognize a current utterance, (3) an utterance aligner coupled to the acoustic model compensator and configured to align the current utterance using recognition output and (4) a convolutive distortion factor estimator coupled to the utterance aligner and configured to estimate an updated convolutive distortion factor based on the current utterance using differential terms but disregarding log-spectral domain variance terms.