Abstract: An approach for efficiently reducing background noise from speech signal in real-time applications is presented. A noisy input speech signal is processed through an inverse filter when the spectrum tilt of the input signal is not that of a pure background noise model the noisy input signal is also filtered in order to reduce the spectrum valley areas of the noisy input signal when the background noise is present.

Abstract: Answer tone received at answering-side gateway and first classification signal is transmitted to a calling-side gateway that generates an answer tone in response to the signal. A second classification signal may be transmitted to the calling-side gateway that adjusts the answer tone in response to the second signal.

Abstract: There is provided a method of updating a noise state of a voice activity detector (VAD) for indicating an active voice mode and an inactive voice mode. The method comprises receiving an input signal having a plurality of frames, determining an elapsed time since the last update of the noise state, updating the noise state of the VAD if the elapsed time exceeds a predetermined time, determining an average minimum energy based on two or more of the plurality of frames, determining a current minimum energy based on a current frame of the plurality of frames, updating the noise state of the VAD if the average minimum energy is less than the current minimum energy, and updating the noise state of the VAD if the average minimum energy is greater than the current minimum energy plus a first predetermined value.

Abstract: Incoming bit stream is processed by a single state machine into a circular buffer. Circular buffer accumulates subunits of data to form a major data unit. State machine recognizes the start of major data unit and flags the location of the major data unit in the circular buffer.

Abstract: A method and apparatus is disclosed for interfacing an asynchronous network with a synchronous network and in particular for efficiently utilizing available bandwidth of a synchronous network transmit opportunity. In one embodiment asynchronous traffic arrives via an asynchronous network at a network device, such as a switch, for transmission over a synchronous network. The traffic is parsed into cells and after switching, a reassembly unit is provided for processing one or more cells buckets. Write operations occur based on an ingress pointer while read operations are controlled by an egress pointer. Upon occurrence of a transmit opportunity on the synchronous network, the entire bandwidth of the transmit opportunity is utilized by loading awaiting cells from bucket memory on to the synchronous network. Sufficient cells are stored in memory between the memory locations identified by the ingress pointer and the egress pointer to insure total utilization of transmit opportunity bandwidth.

Abstract: A trans-impedance amplifier receives an input current and is operable to generate an output voltage responsive to the input current. The amplifier is responsive to an increased range of input currents and has a wide bandwidth. The amplifier includes an input stage having a first and a second transistor and is configured to receive the input current. The amplifier includes an output stage coupled to the input stage and having a third and a fourth transistor. A variable resistor is coupled to the output stage to adjust the amount of current in the output stage. A variable current source is coupled to the output stage and is operable to adjust the amount of current in the output stage. A output driver, which is coupled to the output stage, includes at least another transistor. The output driver is operable to provide the output voltage and is operable to reduce the output impedance of the amplifier.

Abstract: There is provided a method for handling a destructive break for use by a first gateway device, where the first gateway device is in communication with a second gateway device over a packet network, the first gateway device is connected to a first modem over a first communication line and the second gateway device is connected to a second modem over a second communication line. The destructive break is received by the first gateway device from the first modem or the second gateway device. The first gateway device controls a sequence of steps of transmitting the received destructive break and discarding data. Further, the first gateway device receives a break acknowledgement in response to transmitting the destructive break and controls a sequence of steps of transmitting the received break acknowledgement, resetting trans-compression engines at the first gateway device and resumption of data transfer.

Abstract: Various systems and methods for error correction of instructions in an instruction cache coupled to a processor are provided. In one embodiment, a plurality of instructions stored in the instruction cache are fetched for execution by the processor, each of the instructions being fetched during a respective one of a plurality of instruction cycles of the processor. Error detection is performed for each of the instructions concurrently with the fetching of a respective one of the instructions.

Abstract: According to one exemplary embodiment, a communication device comprises a line driver, where the line driver provides an output signal. The communication device further comprises a digital echo canceller module coupled to the line driver, where the digital echo canceller module receives an echo reference signal determined by the output signal of the line driver, where the echo canceller module outputs an echo cancellation signal, and where the echo cancellation signal is capable of canceling linear and non-linear components of a composite signal. The communication device further comprises a summation module coupled to the digital echo canceller module, where the summation module receives the echo cancellation signal and the composite signal, and where the composite signal comprises a received signal and the linear and non-linear echo components. The summation module is configured to subtract the echo cancellation signal from the composite signal and to output the received signal.

Abstract: Various apparatuses, methods, computer programs, and other systems are disclosed for facilitating testing of a module. In embodiment, a method is provided that comprises the steps of creating a plurality of tasks in a computer system, each of the tasks comprising a list of commands that are sent to a plurality of test devices, the test devices comprising the module to be tested and at least one controlled device interfacing with the module during a test of an operation of the module. In addition, the tasks are organized according to a multi-level hierarchy. The tasks are executed according to an order inherent in the multi-level hierarchy, wherein the execution of each task entails communicating the commands of each task to a respective one of the test devices.

Abstract: System and method for dynamically altering bandwidth allocation to each region serviced by a network. Each region is allocated an initial estimated bandwidth on the network and compares instantaneous demand against the allocation. When demand falls below the allocation, the region releases bandwidth so other regions can take advantage of that bandwidth. When demand exceeds the allocation, the region takes advantage of bandwidth released by other regions.

Abstract: A trans-impedance amplifier receives an input current and is operable to generate an output voltage responsive to the input current. The amplifier is responsive to an increased range of input currents and has a wide bandwidth. The amplifier includes an input stage having a first and a second transistor and is configured to receive the input current. The amplifier includes an output stage coupled to the input stage and having a third and a fourth transistor. A variable resistor is coupled to the output stage to adjust the amount of current in the output stage. A variable current source is coupled to the output stage and is operable to adjust the amount of current in the output stage. A output driver, which is coupled to the output stage, includes at least another transistor. The output driver is operable to provide the output voltage and is operable to reduce the output impedance of the amplifier.

Abstract: According to a disclosed embodiment, an endpointer determines the background energy of a first portion of a speech signal, and a cepstral computing module extracts one or more features of the first portion. The endpointer calculates an average distance of the first portion based on the features. Subsequently, an energy computing module measures the energy of a second portion of the speech signal, and the cepstral computing module extracts one or more features of the second portion. Based on the features of the second portion, the endpointer calculates a distance of the second portion. Thereafter, the endpointer contrasts the energy of the second portion with the background energy of the first portion, and compares the distance of the second portion with the distance of the first portion. The second portion of the speech signal is classified by the endpointer as speech or non-speech based on the contrast and the comparison.

Abstract: A fast startup procedure for a modem system utilizes known characteristics of a previously established communication channel to reduce the initialization period associated with subsequent connections over the same channel. In response to the establishment of a call, the modem devices determine whether the fast connect protocol is supported. If so, then the called modem transmits a modified answer tone to the calling modem. The calling modem analyzes the signal received in response to the modified answer tone to determine whether characteristics of the current channel are similar to stored characteristics associated with a previous connection over the same channel. If a channel “match” is found, then the modem devices carry out a fast initialization routine that eliminates, abbreviates, or modifies a number of procedures or protocols that are carried out in conventional modem startup processes.

Abstract: A method and apparatus is disclosed for optic signal power control to maintain a desired or optimum optic signal power level. During start-up, a default or target value from memory may be utilized to bias or otherwise control operation of an optic signal generator or driver. During operation, pre-stored values may continue to be utilized or an open loop or closed loop control system may be utilized. An open loop control system may incorporate a temperature module or a timer module to account for changes in environment or changes due to aging that may undesirably affect system operation. A closed loop control system may incorporate one or more feedback loops that generate a compensation value to account for detected changes. In one configuration one or more peak values of the actual optic signal, or a portion thereof, are detected and processed to generate the compensation signal.

Abstract: There is provided a method of selecting a pitch lag value from a plurality of pitch lag candidates for coding a speech signal. The method comprises identifying the plurality of pitch lag candidates from a frame of the speech signal using correlation; classifying the speech signal to obtain a voice classification; determining whether one or more of the plurality of pitch lag candidates are in a temporal neighborhood of one or more previous pitch lag values; favoring the one or more of the plurality of pitch lag candidates determined to be in the temporal neighborhood of the one or more previous pitch lag values, by adaptive weighting, over other ones of the plurality of pitch lag candidates; and selecting the pitch lag value based on the voice classification and the one or more of the plurality of pitch lag candidates favored by the adaptive weighting.

Abstract: A method and apparatus is disclosed for optic signal power control to maintain a desired or optimum optic signal power level. During start-up, a target value from memory may be utilized to control one or more power levels of an optic signal. There may comprise 2 or more different power levels for the optic signal. During operation, target values may continue to be utilized or an open loop or closed loop control system may be utilized. Compensation may occur for both additive noise/distortion and multiplicative noise/distortion. The compensation for one power level may be expanded or extrapolated to compensate for additive noise/distortion and multiplicative noise/distortion that affect other power levels.

Abstract: Methods and systems are provided for use in a MoIP system including a first modem, a second modem and a third modem. An exemplary communication method includes the steps of receiving a call from the first modem by the second modem over a telephone line, contacting the third modem by the second modem over a packet network, receiving information, from the third modem by the second modem, relating to one or more data compression protocols supported by the third modem, handshaking by the second modem with the first modem to establish a connection, and negotiating a first data compression protocol by the second modem with the first modem, wherein the first data compression protocol is according to the information relating to one of the one or more data compression protocols.

Abstract: There is provided a speech encoding system that receives a speech signal. The speech encoding system comprises a frame processor for processing a frame of the speech signal, where the frame processor includes a pitch gain generator that derives unquantized pitch gains, and a first vector guantizer that receives the unquantized pitch gains and generates quantized pitch gains. The speech encoding system also comprises a subframe processor that begins subframe processing after the pitch gain generator has derived the unquantized pitch gains and the first vector quantizer has generated the quantized pitch gains.

Abstract: There is provided a voice activity detection method for indicating an active voice mode and an inactive voice mode. The method comprises receiving an input signal having a plurality of frames, determining whether each of the plurality of frames includes an active voice signal or an inactive voice signal, determining a second reflection coefficient for each frame determined to include the inactive voice signal, comparing the second reflection coefficient with a reflection threshold, and selecting the active voice mode if the second reflection coefficient is greater than the reflection threshold. The method may further comprise selecting the inactive voice mode if the second reflection coefficient is not greater than the reflection threshold. The method may also comprise analyzing the input signal to determine an energy level of the input signal, and selecting the active voice mode if the energy level is greater than an energy threshold.