International Business Machines Corporation

Asic North

Stephen J Stratz

Edward Kelley Evans

R Michael West

James R Robinson

Jerry P Knickerbocker, Jr

Michael J Slattery

Circuitry for determining timing characteristics, for example, access time, setup time, hold time, recovery time and removal time, of as-manufactured digital circuit elements, such as latches, flip-flops and memory cells. Each element under test is embodied in variable-loop-path ring oscillator circuitry that includes multiple ring-oscillator loop paths, each of which differs from the other(s) in terms of inclusion and exclusion of ones of a data input and a data output of the element under test. Each loop path is caused to oscillate at each of a plurality of frequencies, and data regarding the oscillation frequencies is used to determine one or more timing characteristics of the element under test. The variable-loop-path ring oscillator circuitry can be incorporated into a variety of test systems, including automated testing equipment, and built-in self test structures and can be used in performing model-to-hardware correlation of library cells that include testable as-manufactured digital circuit elements.

Variable-loop-path ring oscillator test circuit and systems and methods utilizing same

A graphics system comprising a format processor for receiving display data including pixel data and color-blending information for at least two (2) separate display layers, a color blender and color processors. The pixel data includes color information for the display layers. The color-blending information determines weighting factors for use in blending the colors of the display layers. The format processor outputs separate streams of pixel data, one for each display layer, as well as the weighting factors. Each stream of pixel data outputted by the processor is inputted into a corresponding color processor that assigns colors to a particular display layer according to the color information in the corresponding pixel data. The color blender blends the colors assigned to the display layers according to the weighting factors.

Graphics system and process for blending graphics display layers

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Shelburne, VT, United States of America

Stephen J Stratz