| 摘要 |
PURPOSE:To provide an electronic clock in which no time error accumulates and no manual time adjustment is required by providing a circuit for receiving broadcasting wave, a time-signal frequency discriminating circuit, a circuit for generating second-resetting signal and a clock circuit for calibrating and indicating time information. CONSTITUTION:A circuit 1 for receiving broadcasting wave receives frequency for time-signal by the broadcasting wave and outputs audio frequency signal A. The signal A is fed to a time-signal frequency discrimination circuit 2, where time signal on the hour is solely converted to logic level time signal B and fed to a second-resetting signal generating circuit of 3. A clock circuit 4 outputs input-gate signal C to be circuit 3 near and on the hour. At the circuit 3 time- signal output other than the time signal or the hour is neglected by an AND logic of the signal B and the signal C, and consequently the time signal on the hour is solely output as second-resetting signal pulse D. The pulse D turns into second-resetting differential signal pulse E and the pulse E goes through a shaping circuit to obtain second-resetting signal F. The signal F is fed to a reset terminal of the circuit 4 and therewith time information is calibrated and indicated. |
