| 摘要 |
PURPOSE:To control a sound signal at night automatically by dividing one day into two time bands, inhibiting the sound signal in the 1st time band and generating the sound signal every 30min in the 2nd time band and every 15min in the 3rd time band. CONSTITUTION:At the time band from 7 a.m. to 8:45 p.m., the outputs 9a-9c of a discrimination circuit 9 are ''0'' and gates 19-21 are opened. Pulse generators 15-17 generate a pulse successively at 15min, 30min and 45min. At the time slightly before a just o'clock, a switch 24 is closed, and at the just o'clock, a pulse generator 14 generates a pulse to generate the sound signal every 15min. At the time bands from 9 p.m. to 10:45 p.m. and from 5 a.m. to 6:45 a.m., the outputs 9b, 9c of the circuit 9 are turned to ''1'' and the sound signal is generated every 30min. At the time band from 11 p.m. to 4:45 a.m., the output 9a of the circuit 9 is turned to ''1'' and the sound signal is inhibited. At that time, sound volume can be automatically controlled. |
