Lucent Technologies Inc.

Other

Agere Systems Inc.

At+t Corp.

Agere Systems Guardian Corp.

David Arthur Rich

Steven R Norsworthy

H Scott Fetterman

Krishnaswamy Nagaraj

Makeshwar Kothandaraman

Bijit Thakorbhai Patel

Robert William Walden

Kadaba R Lakshmikumar

Khong-Meng Tham

Robert O Peruzzi

Michael Holmberg

Brant P Braeges

Harold Joseph Wilson

An amplifier adapted to generate an analog output signal in response to a digital input signal and having an output stage powered by a power-supply circuit, which generates one or more power rails for the output stage such that at least one of these power rails tracks the output signal and substantially represents a biased and half-wave rectified version of that output signal.

Amplifier having half-wave tracking power rails

A data storage drive, a method of manufacturing the same, and a drive array that includes multiple such disk storage drives. In one embodiment, the disk storage drive includes: (1) a substrate, (2) a motor located on the substrate, (3) a data storage medium coupled to the motor for movement thereby and (4) a MEMS read arm located on the substrate, having a read head and capable of responding to control signals by moving to cause the read head to traverse portions of the data storage medium thereby to read data therefrom.

MEMS disk drive and method of manufacture therefor

A multistage converter and method for converting a sampled analog signal to a corresponding digital representation. Each stage of the converter receives an analog input signal and produces a partial digital output. A first stage receives the sampled analog signal as the analog input signal. Each stage provides a residue output, which is the analog input signal to a subsequent stage. The residue is the analog input signal to the stage, less the analog equivalent of the partial digital output from the stage, possibly with a gain change. A voltage range over which a sample of an analog signal can vary is defined by a lower limit and an upper limit. A lower comparator threshold is established within the voltage range. An upper comparator threshold is established within the voltage range, between the lower comparator threshold and the upper limit. The analog input to the stage is quantized based on the lower and upper comparator thresholds to generate a quantized sampled analog signal. When the quantizes sampled analog signal is between the lower and upper comparator thresholds, dither is added to the quantized sampled analog signal to produce the partial digital output. The partial digital outputs from each stage are provided to an error corrector circuit that removes redundancy and effects of the dither and generates the digital representation corresponding to the sampled analog input. The effect of dither is to improve the spurious free dynamic range (SFDR) of the digital representation of the analog input.

Multistage converter employing digital dither

A package assembly consisting of an electronic and/or optical component mounted on a circuit board and sealed to a housing, the housing having a hole therethrough to provide access to the component and being filled with an organic encapsulant material, the seal surrounding the access hole to prevent flow of the encapsulant material therethrough, wherein the seal consists of an integral sealing member having an aperture therethrough in alignment with the access hole and being prepared from a gel-type material, the preferred gel-type material being a silicone and/or fluorosilicone.

Means for sealing an electronic or optical component within an enclosure housing

A method and device for controlling the common-node output voltage of a differential buffer is disclosed. According to the invention, the common-mode output voltage of the differential buffer is controlled to a desired value by supplying a first current to the output of the differential buffer and supplying a second current to the output of the differential buffer, the second current being opposite in polarity and lower in magnitude than the first current. The common-mode output voltage of the differential buffer is sensed and an adjustment current is added to the second current to adjust the common-mode output voltage to the desired value.

Method and apparatus for controlling the common-mode output voltage of a

A current source includes a first current mirror and a second current mirror that share a common current path. The current in the common current path mirrors a current of a current reference connected to the first current mirror. A current in an output current path of the second current mirror mirrors the current of the common current path. A first feedback loop controls the current in the common current path and a second feedback loop matches a voltage of the common current path with an output voltage. The cooperation of the first and second feedback loops ensures that the output current replicates the current of the current reference even when an voltage of the current source is close to the supply voltage. Thus, the voltage swing of the current source output voltage is increased and a precision current source is provided even when the output voltage is close to the supply voltage.

Precision current source

Briefly, in accordance with one embodiment of the invention, a circuit comprises: a sigma-delta modulator including an input signal port, an output signal port, and a signal path. The signal path includes a feedforward signal path and a feedback signal path. The signal path is adapted to be coupled to a dither signal and the circuit is adapted to adjust the dither signal substantially in accordance with a signal applied to the input signal port. In accordance with another embodiment of the invention, a method of improving the stability of a sigma-delta modulator, the modulator employing dither, comprises the steps of: applying a signal to the input port of the sigma-delta modulator; applying a dither signal to the signal path of the sigma-delta modulator; and adjusting the dither signal applied substantially in accordance with the signal applied to the input port.

Method of improving the stability of a sigma-delta modulator employing

In accordance with one aspect of the invention, a liquid crystal display driver for driving liquid crystal display electrodes, comprises: a voltage signal generator adapted to provide a predetermined voltage signal to the liquid crystal display electrodes, the voltage signal generator being further adapted to be activated when the voltage signal level of said electrodes is outside a predetermined dead zone region, the voltage signal generator being deactivated when the voltage signal level of the electrodes is substantially within the predetermined dead zone region; and a switch adapted to couple the voltage signal generator to at least one of said liquid crystal display electrodes. In accordance with another aspect of the invention, a method for providing voltage signals to electrodes of a liquid crystal display, comprising the steps of activating a first voltage signal generator to provide a voltage signal for the electrodes when the voltage signal level of the ectrodes falls outside a dead zone region; and deactivating the first voltage signal generator when the voltage signal level of the electrodes falls within the dead zone region.

Liquid crystal display driver

Briefly, in accordance with one embodiment of the invention, a current source comprises: a first and a second current path, the current paths being coupled so as to provide, during circuit operation, first and second currents through the respective current paths in a substantially predetermined direct proportion. The current source further includes an operational amplifier having its respective input terminals coupled to the first and second current paths, the operational amplifier being coupled in a feedback configuration so as to maintain substantially equal voltages between a first and second predetermined point respectively located along the first and second current paths. Furthermore, the respective first and second currents are related to the respective first and second voltages substantially in accordance with the junction diode equation.

PTAT current source

A device comprises: an analog-to-digital converter; a digital signal processor; a digital dither signal generator; and a signal coupling device adapted to selectively couple one of the dither signal generator and the digital signal processor to the signal path in the converter. A method of testing a dithered analog-to-digital converter employing an M-bit digital signal generator, M being a positive integer, comprises the steps of: generating an M-bit, periodic signal; providing the generated signal to the dithered converter at a point along the signal path of the dithered converter in place of the dither signal; and measuring the digital output signal produced by the converter.

Circuit and method for testing a dithered analog-to-digital converter

An improved adaptive notch filter for removing undesired cochannel FM interference includes in-phase and quadrature signal processing paths in which the undesired FM signal is translated to zero frequency, i.e. to DC. In each of the in-phase and quadrature phase signal paths, a first multiplier translates the input frequency spectrum in a dynamic manner so that the frequency of the undesired FM signal is always centered on DC. The undesired signal, now at DC, is filtered out by a high pass filter with a sharp rolloff. The output of the high pass filter is remultiplied in a second multiplier to translate the desired FM signal back to the original position in the frequency spectrum. In order to eliminate an unwanted difference frequency remodulation signal at the output of the second multiplier, the quadrature phase signal path performs a parallel operation on the same input signal, but with a quadrature phase (90 degree phase shift) control signal. The output the in-phase and quadrature signal processing circuits are combined in an adder circuit to cancel the unwanted difference frequency remodulation signal.

Growing community of inventors

Whitehall, PA, United States of America

David Arthur Rich