Rensselaer Polytechnic Institute

Thomas W Krawczyk

John F McDonald

Matthew W Ernest

According to one embodiment of the invention, a ring oscillator is provided that includes a number of stages, each of the stages being coupled to an output of at least two previous stages. This architecture is referred to hereinafter as a &ldquo;feed forward&rdquo; architecture, as signals are fed forward to further stages beyond a consecutive stage. Any number of stages may be used. This architecture represents a new topology for ring oscillator design, as ring oscillators generally include consecutive stages that each have an input from the previous stage only. In general, such an architecture achieves higher frequencies than oscillators without feed forward paths.

Feed forward voltage controlled ring oscillator

A multiplexer is provided that is symmetric in that substantially the same delay is experienced from any input of the multiplexer to the multiplexer output. It is realized that in conventional serial transmission systems, standard Current Mode Logic (CML) multiplexers are used which are asymmetric and exhibit different delays between select and data inputs. Because of these delays, conventional transmission systems experience jitter at high frequencies. To extend the operable range of communication systems, a symmetric multiplexer may be used which has substantially the same delay from any input to the multiplexed output, thus reducing jitter. For example, the multiplexer may be part of a communication system having a serial data transmission circuit.

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Troy, NY, United States of America

Thomas W Krawczyk