International Business Machines Corporation

Scott David Huss

Hayden C Cranford, Jr

Michel F Ferry

John Lock Creigh

Thomas Ashford Hughes, Jr

A data transmitter is provided which performs digital to analog conversion, convolution with an arbitrary finite impulse response, and smoothing of the output functions without requiring a separate anti-aliasing low pass filter. To implement the data transmitter, a digital input data value is convolved with a desired impulse response. The coefficients of the desired finite impulse response filter are chosen to create a first or second derivative of an output of the data transmitter. Then, the derivative is integrated so that a resulting signal output from the data transmitter is a smooth signal which does not require further filtering.

Data transmitter and method therefor

A method and apparatus for equalizing a communications signal transmitted through a transmission medium includes an integrated continuous-time filter and circuitry for developing a feedback signal to compensate for distortion in the signal caused by the transmission medium. The control signal adjusts the transfer characteristics of the integrated continuous-time filter thereby compensating for loss and distortion of the signal caused by the transmission medium and further tunes the integrated continuous-time filter thereby compensating for semiconductor process variations in the integrated continuous-time filter.

Integrated adaptive cable equalizer using a continuous-time filter

A method and apparatus for reducing reference frequency signal and/or clock switching noise in self-tuned integrated continuous-time filters. In the master-slave automatic tuning scheme, one or more sample-and-hold circuits sample and hold the frequency control signal and Q-control signal generated by the feedback loop(s) of the automatic tuning system. The control signals are held at a constant level for a period of time during which the reference frequency signal and/or clock signal are quiescent. At one or more predetermined times, the frequency control and Q-control signals are intermittently updated to automatically tune the slave filter.

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Raleigh, NC, United States of America

Scott David Huss