Wireless Clock System and Method

Abstract

A wireless clock system includes a master clock or other master time source, and a plurality of slave clocks or repeater devices. Each slave clock can both wirelessly receive and wirelessly transmit time signals including current time data. To avoid conflicts among the slave clocks, each slave clock transmits time signals in a frequency-hopping manner over pseudo-randomized frequencies and at pseudo-randomized transmission start times. In another embodiment, power consumption at the slave clocks is minimized by activating and deactivating receivers within the slave clocks at predetermined times and at predetermined intervals, each interval being longer than the previous interval, until valid time signals are received from either the master clock or another slave clock. Calibration of the slave clock's time base is also performed.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is entitled to the benefit of U.S. Provisional Patent Application Ser. No. 60 / 565,937, filed Apr. 27, 2004. Such application is incorporated herein by reference.FEDERALLY SPONSORED RESEARCH[0002]Not ApplicableSEQUENCE LISTING OR PROGRAM[0003]Not ApplicableBACKGROUND OF THE INVENTION[0004]Traditional wireless clock systems known in the market today typically consist of a “master” clock having a wireless transmitter and multiple secondary or “slave” clocks having wireless receivers. The secondary clocks may be installed in many rooms in a school, industrial location, large office building or the like. One reason for using a “master-slave” type system is to permit the master clock to maintain the time at all of the secondary clocks in synchronization with the time at the master clock. To do this, typically, the master clock transmits a periodic time signal, correction signal or the like to the secondary clocks. The secondary ...

AI Technical Summary

Benefits of technology

This solution allows for the creation of clock systems of almost unlimited size with minimized signal conflicts, ensuring accurate time synchronization across large distances and noisy environments by using slave clocks as repeaters and employing frequency hopping and pseudo-randomized transmission techniques.

Problems solved by technology

A disadvantage of such a system is that the size of the system is limited to the distance between the master clock transmitter and the secondary clock receivers.

Over a long distance, or in electrically noisy or interfering environments, the secondary clocks may not be able to receive valid time signal data from the master clock.

Another disadvantage of this type of system is that the master clock transmitter normally transmits the time signal over a single radio frequency.

Therefore, if there is noise or interference at or near that frequency, it will most likely affect the ability of the secondary clocks to receive accurate time data, unless the transmission frequency is changed manually.

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