| 摘要 |
PURPOSE:To output a high accuracy dial tone at a comparatively low oscillation frequency that normal timepieces use by doubling a frequency by a multiplier means. CONSTITUTION:A multiplier circuit 10 doubles the frequency (32. 768 kHz)of an inputted clock signal to a frequency (65. 536k Hz) and transmits it to data ROMs 13a and 13b. They divide said frequency to the prescribed frequencies in low or high groups. In order to obtain low frequencies R1-R4, for instance, the frequency 32. 768 kHz is divided by 94, 85, 77 and 70. In order to obtain high frequencies C1-C4 said frequency is divided by 54, 49, 44 and 40. The spiral waveform obtained in the data ROMs 13a and 13b is smoothed by ladder networks 14a and 14b, and synthesized by an adder circuit 15. And the synthesized wave is outputted as a dial tone from a speaker 16.
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