| 摘要 |
PURPOSE:To supply always precise clocking information even if noises or voices having the same frequency as a correct time signal are received by receiving pre-time signal and a correct time signal generated from a broadcasting station and checking the arrival of the pre-time signal before the arrival of the correct time signal. CONSTITUTION:When pre-time signals are generated like 59'57'', 59'58'' and 59'59'' every second from the broadcasting station, a receiver 2 receives these pre-time signals from an antenna 7. Correct time signals are extracted from these received pre-time signals by a pre-time signal extracting circuit 3 and the correct time signals 8 are outputted. Since correct time signals 8 are respectively received after 1sec from these three pre-time signals 9 every second, a correct signal generating circuit 5 decides that the correct time signals 8 are correct time and outputs time corrected signals 10 to a clocking circuit 6. Even if sound included in voices or music and having the same frequency as that of the correct time signals is received and the correct time signals 8 are transmitted, the circuit 5 does not regard the signals 8 as correct time because the pre-time signal 9 has not been previously inputted. Thus, the always precise time information can be supplied. |
