| 摘要 |
<p>A tone generator includes a controller for generating a frequency control signal, an address control signal, a tone period control signal and an automatic tone period mode, a sinusoidal wave generator having a nonvolatile table of a sampled value of pi /2 period for synthesizing two single frequencies generated by dividing temporally the sampling frequency output from the nonvolatile table and outputting a dual sinusoidal wave, a gain signal generator for generating a gain signal, a multiplier for multiplying the sinusoidal wave and the gain signal to output tone sampling data, a pulse code modulator for pulse-code-modulating the tone sampling data to output a pulse code modulation code, a serial converter for converting the pulse code modulation code into a serial bit, a tone period control signal generator having a tone period memory and a timer, for outputting a tone period control signal of the controller when the automatic tone period mode of the controller is not activated, and outputting a tone period control signal of the timer according to a counter value output from the tone period memory by the address control signal when the automatic tone period mode is activated, and a switch for switching and outputting a signal output from the serial converter according to the tone period control signal.</p> |
