| 摘要 |
An absolute digital clock system which is capable of counting absolute time despite the disruptive effects of a nuclear event, or other disturbance, on the electronic circuitry of the system. The clock system of the invention includes a master quartz crystal oscillator stage, and a string of counter stages connected thereto each including a binary counter for counting down from the frequency of the preceding stage to a lower frequency, and each including a crystal oscillator phase-locked with the binary counter and producing a signal at the lower frequency. During the period of time when the radiation level is too high for adequate electronic functioning, the quartz crystals in the master stage and subsequent counter stages continue to vibrate without significant loss of phase information due to the high mechanical inertia of the quartz crystals, and this mechanical inertia of the various crystals is used in the system of the invention to enable the system to continue to indicate absolute time despite an interruption of substantial length as compared with the period of vibration of the individual crystals.
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