| 摘要 |
<p>A holding sound generator circuit, for a telephone, outputs a holding sound to a telephone on the other end of the line. A string of holding sound scales are stored in ROM beforehand, and the holding sound scale range may be read therefrom by a holding designated signal, thus composing a pronunciation signal. For composing the pronounciation signal, the primary clock signal is divided in frequency by a integral or fractional number to obtain a pulse for a desired digital/analog conversion. By setting the frequency-division ratio optionally and down to a decimal, it is possible to set the frequency of the primary clock signal at a low level.</p> |
