| 摘要 |
PURPOSE:To select several signal tones at random to sound, by outputting a detection signal in response to the generation of an alarm signal from an alarm contact at a set time to select a signalling signal according to an output signal of a memory means of a counter following the output. CONSTITUTION:A trigger signal generation circuit 14 receives an input of a signal A from an alarm contact 16 which outputs an alarm signal at a set time and an input of a fixed cycle signal phi1 from a frequency dividing circuit 4 and has an AND gate 28, an FF 30 and a counter 32. A detection circuit 21 outputs a detection signal in response to an alarm signal from the contact 16 while having one-shot multivibrator circuits 22 and 24 and an Or gate 26 and is connected to a snooze switch 20. A signalling signal selection circuit 24 comprises a counter 36, FFs 38 and 40, a decoder 42, AND gates 44-50 and a multiplexer 52. A melody signal generation circuit 70 comprising first - fourth melody circuits 72-78 outputs four kinds of melody signals, for instance. A sound generation circuit 68 outputs a melody output signal to always sound a fresh signal tone.
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