초록 ▼

An electronic time-of-day clock having a low-power time source and compensation circuits selectively operable responsive to pulses output from the low-power time source when system primary power is off or disabled, and responsive to a relatively highly accurate time-pulse generator when primary powe

An electronic time-of-day clock having a low-power time source and compensation circuits selectively operable responsive to pulses output from the low-power time source when system primary power is off or disabled, and responsive to a relatively highly accurate time-pulse generator when primary power is enabled. The time-of-day clock compensates continuously in real-time for errors in the output of the low-power time source caused by variations in the ambient temperature of the device; when primary power is enabled, the output of the low-power time source is further compensated by comparing the output thereof with the output of the high-accuracy frequency standard and storing accumulated error.

대표청구항 ▼

Electronic apparatus including a time-of-day clock, said apparatus comprising: primary means for supplying operating power to said apparatus; secondary means for supplying power to said time-of-day clock; means powered by said secondary power supply means for generating a first clock signal; means c

Electronic apparatus including a time-of-day clock, said apparatus comprising: primary means for supplying operating power to said apparatus; secondary means for supplying power to said time-of-day clock; means powered by said secondary power supply means for generating a first clock signal; means coupled to said first clock signal generating means for generating indicia representing a period of time; means powered by said primary power supply means for generating a second clock signal having a frequency and accuracy at least one order higher than the first clock signal; and microprocessor means powered by said secondary power supply means and responsive to the indicia for generating data items representing time-of-day, said microprocesor means being clocked by the first clock signal when said primary power supply is disabled and by the second clock signal when said primary power supply is enabled.