Sun Microsystems, Inc.

Stuart Alexander Ridgway

Robert J Bosnyak

Mark R Greenstreet

The clock signal is the dominant source of electromagnetic interference (EMI) for many digital electronic devices. EMI generated by these electronic devices must be suppressed to avoid interference with other electronic devices and to satisfy FCC regulations. The present invention seeks to reduce EMI emissions by phase-modulating the clock signal using tunable delay lines. Phase modulation causes a spreading of the energy spectrum of the clock signal thereby reducing EMI emissions. In addition, the present invention is capable of generating a wide energy spectrum in a short time interval. Furthermore, the present invention can be similarly applied to other signals which exhibit a periodic or timing nature due to a correlation with the clock signal.

EMI reduction using tunable delay lines

A stage of a multi-stage, self-timed datapath circuit calculates one or more data outputs as a function of one or more data inputs. Data outputs are calculated by multiple logical elements that operate simultaneously and produce internal results as inputs to other logical elements within a stage. An internal completion signal generator detects completion of a predetermined set of the internal results calculation and, in response, generates an completion signal for each internal result detected. A done signal generator receives the completion signals and, in response to one or more preselected combinations of the completion signals, provides a done signal. The done signal is generated with a predetermined delay such that the delay is at least as long as a time it takes for the stage to calculate a final result.

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New Brunswick, NJ, United States of America

Stuart Alexander Ridgway