National Instruments Corporation

Gabriel L Narus

Craig M Conway

Rodney D Greenstreet

Jason W Frels

Mark R Wetzel

Techniques and systems for synchronizing a clock via a backplane. An apparatus includes a backplane, a clock coupled to or included in the backplane, a synchronization interface, and at least one processing element coupled to the clock via the backplane and coupled to or including the synchronization interface. The at least one processing element may be configured to compare first time information received from the clock via the backplane with second time information received from the synchronization interface. The second time information may be associated with an external clock. The at least one processing element may determine adjustment information based on the comparison and synchronize the clock with an external clock using the adjustment information, via the backplane. The apparatus may be a PXIe chassis. The clock output may be sent to modules plugged into the backplane in order to synchronize them with an external chassis clock, for example.

Backplane clock synchronization

A system and method for aligning a local timebase to a remote timebase given a timebase error value from a higher-level protocol, and using the aligned timebases to generate and distribute synchronized events and synchronized adjustable frequency periodic signals across a domain using the aligned timebases. Slightly speeding up or slowing down a periodic signal used to count time, a local timebase may be aligned to a remote timebase when given an error value from a higher-level protocol. A device may be configured to begin generating a periodic waveform at an agreed upon time in the future, once the timebases are aligned, where the time may be synchronized to remote devices via a synchronization protocol and an alignment mechanism. Remote periodic signals may remain synchronized to each other as long as the higher-level protocol and timebase alignment algorithm keep the timebases aligned. A common reference periodic signal may be shared between all devices, and the reference periodic signal or a conditioned version of the reference periodic signal may be specified as the periodic signal to control the operation of the timebase circuitry. The common reference periodic signal may improve synchronization performance beyond the capabilities of the higher-level protocol, and may in addition provide means for synchronization fault tolerance.

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Austin, TX, United States of America

Gabriel L Narus