| 摘要 |
An electronic alarm watch including an oscillator for developing a repetitive time standard signal, a dividing circuit for dividing the time standard signal to develop repetitive output signals, and a counting circuit receptive of one of the repetitive output signals of the dividing circuit for counting the same to develop a count representing passage of time. A first waveform shaping circuit receives the output signal of the counting circuit and a higher repetition rate output signal of the dividing circuit for developing a pulse signal at a repetition rate equal to that of the counting circuit output signal and having a pulse width equal to that of the dividing circuit output signal. A coincidence detector detects when the count of the counting circuit and an alarm time signal coincide and develops an output signal in response to this condition. A second waveform shaping circuit receives the output of the coincidence detector for developing in response thereto a pulse signal having a width greater than the pulse width of the output pulse of the first waveform shaping circuit. An alarm responds to an output of the dividing circuit and an enabling signal for developing an alarm signal. A memory circuit responsive to the respective output signals of the first and second waveform shaping circuits applies an enabling signal to the alarm in response to the output of the second waveform shaping circuit, and terminates the enabling signal in response to the output of the first waveform shaping circuit. Accordingly, an alarm signal is developed when coincidence between the counting circuit count and the alarm time signal is detected, and the alarm signal is automatically terminated after an interval equal to the repetition rate of the first waveform shaping circuit output signal.
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