North Carolina State University

Griff Luhrs Bilbro

Wesley E Snyder

Anthony Zilic

Lester C Hall

Wentai Liu

S Mark Clements

Integrated circuits having cooperative ring oscillator clock circuits therein include a plurality of synchronous and asynchronous active devices on the substrate and a plurality of 'cooperative' ring oscillators (CRO) electrically coupled in parallel at respective clock nodes, interspersed on the substrate as a mesh, for example. The ring oscillators, which may have a predetermined number of stages but possibly different size in terms of clock driving capability, are preferably interspersed among the synchronous active devices on the surface of the substrate to provide a 'local' clock signal which is constrained in terms of skew and jitter by the presence of the other parallel-connected ring oscillators at other locations on the substrate. Multiple replications of a ring-oscillator containing three serially connected inverters may result in the formation of a two-dimensional hexagonal network of clock nodes of different phases (e.g., .phi..sub.1, .phi..sub.2 and .phi..sub.3). Connection of the inverters as a hexagonal network also causes 'aggregation' because the arrangement of the inverters in the net places the inverters in parallel. Whenever inverters are connected in parallel, an 'aggregated' inverter is formed having an effective width equal to the arithmetic sum of the widths of the all the individual inverters of the same phase. This 'aggregation' compensates for process variations because the 'faster' and 'slower' inverters tend to cancel each other out during signal transitions. The benefits of aggregation are also independent of the size of the IC so efficient scaling can be readily achieved. Ring oscillators of larger size (e.g., widths) can also be placed in close proximity to those portions of the circuit which have high load synchronous active devices therein, to inhibit local variations in skew and jitter.

Integrated circuits having cooperative ring oscillator clock circuits

An array of optical fiber bundles includes one or more diffractive elements positioned above gaps between adjacent bundles. Incident radiation produces mathematically determinative diffraction patterns on the respective input faces of the adjacent bundles. Radiation intensity values for areas between and along the abutting edges of adjacent optical fiber bundles can be determined using the diffraction patterns. These intensity values can be assigned to other pixels so that precise, seamless images can be reconstructed.

Systems and methods for using diffraction patterns to determine

An array of tapered optical fiber bundles having input faces for receiving incident radiation thereon are staggered with respect to one another such that an input face edge portion of a tapered optical fiber bundle overlies a portion of an input face of an adjacent optical fiber bundle so as to occlude the overlaid portion from incident radiation. Optical fiber bundles may be staggered in various configurations, including repeating patterns.

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Raleigh, NC, United States of America

Griff Luhrs Bilbro