| 摘要 |
A wristwatch equipped with a dialing tone generator employs a low-frequency oscillator as a reference signal oscillator. The reference signal is frequency-divided into first and second frequency-divided signals, the first frequency-divided signal being used to produce a low-frequency tone signal, the second frequency-divided signal being used to produce a high-frequency tone signal. Both these tone signals are rectangular waveforms which are filtered in corresponding low-pass filters, to output first and second sine-wave signals, which are then synthesized with each other to produce a desired dialing tone.
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