International Business Machines Corporation

John Lock Creigh

Francis Edward Noel, Jr

Michel F Ferry

Lorrie Ann Tomek

Jerry Dagher

Scott David Huss

James W Sylivant

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

Variable length LAN frames can be segmented into fixed length cells to allow the data in the frames to be transported through an intermediate cell-based system, such as an ATM network. Where transport through the intermediate system results in time gaps between data units extracted from the cells, special symbol combinations can be inserted into the time gaps to permit frame-representing data to be forwarded toward its destination as a 'stretched frame' without waiting for all the cells representing the frame to arrive. When a stretched LAN frame is received at a 'stretch-aware' LAN station, the special symbol combinations are detected and removed to recover at least the data payload of the original LAN frame.

Method and apparatus for reconstructing LAN frames following transfer

An equalizer circuit suitable for selectively equalizing a transmission media operating at one of a number of different data rates has a number of equalizers, one for each data rate, connected in parallel to the media and a selectively operable means for disabling all but one of the equalizers.

Multi-data rate selectable equalizer

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Raleigh, NC, United States of America

John Lock Creigh