CLOCK DEVICE WITH AUTOMATIC CALIBRATION FUNCTION

摘要

PURPOSE:To enable a time deviation between clocks to be maintained to be a small value by setting an average value of the time deviation between a forecasting signal of time casting and a time casting timing of a clock to be calibrated corresponding to a specified timing position of an actual casting signal to an amount of calibration of time. CONSTITUTION:Low-frequency output signals Pa1 to Pa4 are input to a time casting device 2 by a radio receiver 1 and pulses Pb1 to Pb4 in synchronization with these are obtained by the device 2. The pulses Pb1 to Pb4 are input 5D to a microcomputer 5 at each time casting as a reference time signal and a second signal Pc1 and an hour/minute/1/1000 second signal Pc2 are input 5D from a clock 4 which is in daily use. Error values Tf1 to Tf4 between the pulses Pb1 to Pb4 and one second signal Pc and their average values are calculated by a CPU 5A immediately before an on-the-hour These average values are given to the clock 4 through an output port 5E and are subtracted from a counted value of the clock 4. A carry timing of a counter constituting the clock 4 is modified and a time casting timing is calibrated so that it matches the timing of the time casting.