Hewlett-packard Company

James L Johnson

Leonard S Cutler

Robin P Giffard

John C Eidson

Richard Keith Karlquist

Stanley P Woods

Joseph Alexander Dara-Abrams

James R Collin

Theodore Parisek

An oven assembly for a crystal resonator and oscillator utilizes a thermally symmetrical design to provide a high thermal gain. The oven assembly includes an encasement that forms a hermetically sealed oven chamber that is substantially cylindrical. Concentric with the oven chamber is an annular oven mass that functions as a heat reservoir for the crystal resonator that is contained within the oven mass. The cylindrical oven chamber and the concentric annular oven mass provide two levels of circular symmetry that help achieve a thermally isotropic oscillator environment. Wide-area uniform heat transfer promotes high thermal gain and minimizes thermal gradients. Another factor is the geometry and circuitry for temperature monitoring. Temperature sensors are equidistantly spaced from each other and are equidistant from the center of the oven chamber. Signals from the various thermistors are averaged to provide a more accurate temperature determination for regulating the heaters.

High thermal gain oven with reduced probability of temperature gradient

The local clocks within each node of a loosely distributed network system may be synchronized and syntonized by any of the nodes in the network. Each of the nodes contains a time packet detector (TPD) that detects and recognizes timing data packets and produces a recognition signal. This signal may be used to cause an action in the detecting node, in particular the node may contain a time service block (TSB) containing a local clock that may be used to record the time of the recognition signal. The recorded times may be used as the basis for correcting the local clocks of the nodes in the system. Transfer devices such as gateways, bridges, and routers may include TSBs and TPDs to allow for correction for the transit time of time packets through the transfer device. The TPD is normally connected within the media access device at the point of final encoding for transmission or recovery of the clock and data for receiving where the time jitter will be at a minimum.

Method for recognizing events and synchronizing clocks

An improved atomic beam tube assembly is disclosed in which the operating parameters for the atomic beam tube are contained in a programmable read-only membery located in the end of the cable used for connecting the atomic beam tube assembly to the support electronics. This arrangement eliminates the selected resistors normally used with such beam tube assemblies.

Atomic beam tube assembly

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Scotts Valley, CA, United States of America

James L Johnson