| 摘要 |
PURPOSE:To obtain plural desired oscillating frequencies by oscillating a vibrator when a DC voltage is applied, and also varying an integration circuit constant of a delay circuit at a prescribed period. CONSTITUTION:A step output shown in Fig. 5a exists from a rectifier/power supply circuit 2 when a ringing tone comes, and it is inputted to the 1st delay circuit 5. The 1st delay circuit 5 outputs an integrated waveform as shown in Fig. 5d. A voltage shown in Fig. 5e is applied to the vibrator 9 succeedingly, which is oscillated at a prescribed frequency. When the ringing signal comes as stated above next, a step output is inputted to the 2nd delay circuit 10 from the rectifier/power supply circuit 2, the time constant of an integration circuit is changed by changing the constant of the 1st delay circuit 5 from A to B, and the vibrator 9 is oscillated in a frequency different from the preceding frequency. Thus, in setting the time constant of the integration circuit of the 1st delay circuit 5 shorter than the time constant of the integration circuit of the 2nd delay circuit 10, a waveform as shown in Fig. 6f where the two frequencies decided by the time constant of the 1st delay circuit 5 are repeated by the period decided by the time constant of the 2nd delay circuit 10, is outputted. |
