Abstract: The present invention is generally directed to an optical isolator device, and various methods of making same. In one illustrative embodiment, the method comprises obtaining a single SOI substrate, the SOI substrate having an active layer comprised of silicon and a buried insulation layer, forming a doped layer of silicon above the active layer of the SOI substrate, forming first and second isolated regions in at least the doped layer of silicon, forming a photon generating device in the first isolated region, and forming a photon receiving device in the second isolated region.

Abstract: The present invention is generally directed to a method of forming a p-well in an integrated circuit device. In one illustrative embodiment, the method comprises forming a first layer of epitaxial material above an active layer of a substrate, forming a first doped region in the first layer of epitaxial material, forming a second layer of epitaxial material above the first layer of epitaxial material, forming a second doped region in the second layer of epitaxial material, and performing at least one heat treating process.

Abstract: A method and apparatus is provided for implementing an unbalanced subscriber line interface circuit with built-in ring circuit. A signal to be conditioned is received. An unbalanced output buffering function is performed upon the signal to be conditioned using an unbalanced buffering circuit. Performing the unbalanced output buffering function includes switching between a plurality of power supplies to maintain a predetermined maximum voltage across a plurality of devices relating to the unbalanced buffering circuit.

Abstract: The present invention is generally directed to bipolar transistors with geometry optimized for device performance and various methods of making same. In one illustrative embodiment, the device includes a substrate, an intrinsic base region formed in the substrate, a continuous emitter region formed within the intrinsic base region, the emitter region having a plurality of substantially hexagonal shaped openings defined therein, and a plurality of extrinsic base regions formed in the substrate, wherein each of the extrinsic base regions is positioned within an area defined by one of the plurality of substantially hexagonal shaped openings.

Abstract: A method and apparatus is provided for performing an active impedance feedback. A signal is received. An active feedback synthesis is performed based upon the signal. Performing the active feedback synthesis includes using an active feedback network for conditioning an output signal and performing a signal summation of at least two components of the conditioned output signal for feedback.

Abstract: A method and apparatus is provided. The method includes transmitting a signal having an AC component to a subscriber line and receiving at least a portion of the transmitted signal from the subscriber line. The method includes determining at least a portion of a period of the AC component of the received signal, and performing a function of a line card in response to determining at least the portion of the period of the AC component. The apparatus includes circuitry that is capable of transmitting a signal having at least one of an AC component and a DC component to a subscriber line, and receiving at least a portion of the transmitted signal from the subscriber line. The apparatus includes a filter and computation logic. The filter is capable of filtering the DC component from the received signal. The computation logic is capable of determining a value proportional to a power of the AC component of the received signal over at least a portion of a period of the AC component.

Abstract: The invention relates to a method and an apparatus for receiving and transmitting asynchronous transfer mode (ATM) cell streams over a bus. The invention provides a method for receiving ATM cells in a host from a client over a bus, comprising the steps of determining whether an ATM cell in a first storage device within the client is ready to be transferred over the bus to a second storage device within the host, preventing overflow of the second storage device by calculating a first available cell space in the second storage device as a function of a write value, a read value image and a size value of the second storage device, and transferring an ATM cell from the first storage device to the second storage device.

Abstract: A passive echo cancellation circuit for reducing echoes on a subscriber line includes an output driver adapted to drive a downstream signal on the subscriber line. First sensing circuitry is coupled to the output driver and adapted to sense a current on the subscriber line to generate a first voltage. A balancing network is adapted to receive at least a portion of the downstream signal. Second sensing circuitry is adapted to sense a current in the portion of the downstream signal passing through the balancing network to generate a second voltage. An upstream driver is adapted to subtract the second voltage from the first voltage to generate an upstream signal.

Abstract: A method and apparatus is provided for DC level control in a line card. The method includes receiving a digital input signal, determining a first DC component value of the digital input signal at a first preselected time, and determining a second DC component value of the digital input signal at a second preselected time. The method further includes determining a difference between the first DC component value and the second DC component value. The method includes providing the first DC component value to a digital-to-analog converter in response to determining that the difference is less than a first preselected value. The apparatus includes a digital-to-analog converter and logic. The logic is coupled to the digital-to-analog converter, wherein the logic is capable of receiving a digital input signal, determining a first DC component value of the digital input signal at a first preselected time, and determining a second DC component value of the digital input signal at a second preselected time.

Abstract: A method and apparatus is provided for using a single power supply in a dual mode fashion. A ringing signal is received. A waveform power supply signal based upon the ringing signal. An unbalanced output buffering function upon the signal to be conditioned using an unbalanced buffering circuit. Performing the unbalanced output buffering function includes switching between a plurality of power levels of the waveform power supply signal to maintain a predetermined maximum voltage across a plurality of devices relating to the unbalanced buffering circuit.

Abstract: The present invention is generally directed to an optical isolator device, and various methods of making same. In one illustrative embodiment, the method comprises obtaining a single SOI substrate, the SOI substrate having an active layer comprised of silicon and a buried insulation layer, forming a doped layer of silicon above the active layer of the SOI substrate, forming first and second isolated regions in at least the doped layer of silicon, forming a photon generating device in the first isolated region, and forming a photon receiving device in the second isolated region.

Abstract: The present invention is generally directed to a multi-stage epi process for forming semiconductor devices, and the resulting device. In one illustrative embodiment, the method comprises forming a first layer of epitaxial silicon above a surface of a semiconducting substrate, forming a second layer of epitaxial silicon above the first layer of epitaxial silicon, forming a third layer of epitaxial silicon above the second layer of epitaxial silicon, forming a trench isolation region that extends through at least the third layer of epitaxial silicon and forming a portion of a semiconductor device above the third layer of epitaxial silicon within an area defined by the isolation region.

Abstract: A near full duplex portable handset speakerphone comprises: a microprocessor; a hands-free receive register connected to the microprocessor; a hands-free transmit register connected to the microprocessor; a ROM having a speakerphone operation algorithm, the ROM-connected to the microprocessor; a first analog-to-digital converter connected to the hands-free receive register; a second analog-to-digital converter connected to the hands-free transmit register; a first programmable digital attenuator connected to the microprocessor and to a speaker; and a second programmable digital attenuator connected to the microprocessor and to a microphone, wherein near full duplex communication is achieved without digital signal processing. In another feature of the invention, the hands-free registers provide a digital representation of the speech volume in each direction to the microprocessor.

Abstract: A method and apparatus is provided for performing an active impedance differential current feedback. A signal is received. A current feedback of an output signal in an active feedback synthesis mode is performed based upon the signal. The active current feedback includes using an active feedback network for conditioning an output signal, converting the signal into a differential current signal, and summing at least two components of the differential current signal for performing a differential feedback.

Abstract: A digital wavetable audio synthesizer is described. A synthesizer volume generator, which has several modes of controlling the volume, adds envelope, right offset, left offset, and effects volume to the data. The data can be placed in one of sixteen fixed stereo pan positions, or left and right offsets can be programmed to place the data anywhere in the stereo field. The left and right offset values can also be programmed to control the overall volume. Zipper noise is prevented by controlling the volume increment. A synthesizer LFO generator can ad LFO variation to: (i) the wavetable data addressing rate, for creating a vibrato effect; and (ii) a voice's volume, for creating a tremolo effect. Generated data to be output from the synthesizer is stored in left and right accumulators. However, when creating delay-based effects, data is stored in one of several effects accumulators. This data is then written to a wavetable.

Abstract: The invention relates to an apparatus and a method for accessing memories having a time-variant response over a PCI bus by using two-stage DMA transfers. The invention provides a method for executing a read request over a PCI bus by transferring the requested data from a main memory of a PCI card to a device located on the PCI bus, comprising the steps of obtaining an access request from a read access queue, transferring, by a first DMA transfer, the requested data from the main memory to a buffer memory on the PCI card, and transferring, by a second DMA transfer, the data from the buffer memory to the device.

Abstract: A communications system includes a first and second communication unit coupled together via a radio communications link. In one embodiment, the communications system takes the form of a frequency hopped, spread spectrum digital cordless telephone, where the first unit is a base unit and the second unit is the remote unit. The first and second communication units are respectively set to transmit and receive communication over a first radio frequency during a first time frame, select a second radio frequency during the first time frame, and set to respectively receive and transmit communication over the second radio frequency during a second time frame.

Abstract: An apparatus for detecting at least one tone having a known frequency and duration in an input signal. The input signal is input over a period of time which is divided into frame portions including at least an initial frame portion and a last frame portion. An energy signal indicative of the energy of the input signal during each frame portion is generated. A signal filter receives the energy signal and generates a noise indicator for each frame portion based on whether noise is detected in the energy signal. A dynamic threshold determiner generates an energy threshold for each frame portion. The energy threshold for the initial frame portion is generated based on a minimum expected value of the energy signal for a subsequent frame portion. The energy thresholds for frame portions subsequent to the initial frame portion are generated based on values of the energy signals during previous frame portions and the noise indicator.

Abstract: A method for determining the suitability of a copper line, used for transmitting voice band signals and having one or more user devices coupled thereto for transmitting signals on the copper line, for use in transmitting data signals out-of-band with the voice band signals is provided. The method includes applying a test signal at one point in the copper line. The test signal has a known relationship to a particular out-of-band data transmission scheme. A response of the copper line to the test signal is monitored, as influenced by the one or more user devices. The monitoring takes place at about the point where the test signal was applied. The suitability of the copper line for data transmission using the particular out-of-band data transmission scheme is determined based on the monitored response of the copper line. A method for determining the suitability of a communication line for transmitting data using an out-of-band data transmission protocol is provided.

Abstract: A method and apparatus is provided for impedance matching for an apparatus capable of supporting voice and data. The method includes receiving an input signal having at least one of a voice component, data component, and DC component, and filtering at least a portion of the data component and DC component of the input signal to provide a filtered signal. The method further includes adjusting an input impedance of the apparatus to a first preselected value for the voice band in response to the filtered signal and adjusting the input impedance of the first apparatus from the first preselected value to a second preselected value. The method includes adjusting at least one of a magnitude and phase of the filtered signal to adjust the input impedance to a third value.