Low power timekeeping

Low-power timekeeping methods have been developed that provide improved accuracy over the full military temperature range. These methods provide tradeoffs of accuracy vs. power consumption dependent upon the application. The system achieves this performance by using a microcomputer-compensated crystal oscillator (MCXO) to periodically update a low-power oscillator clock system. This technique does not substantially increase the power dissipation because the MCSO is turned on for only a few seconds each time to recalibrate the clock oscillator frequency. Using this technique, a clock oscillator of +or-5*10/sup -6/ over the temperature range can be made to approach the +or-*10/sup -8/ accuracy of the MCXO.<>