| 摘要 |
<p>In an AC signal generating apparatus a digital sine wave signal of a set frequency, generated by a digital sine wave generating part (23), is converted by a D/A converter (24) to an analog sine wave signal and is then output. The output sine wave signal is converted by an output detector (19) to a voltage mean value, and the difference between it and a reference value is obtained by a comparator (21). The difference is negatively fed back, as a reference voltage (VR), the D/A converter to control its conversion gain so that the difference may approach zero. Thus, a highly accurate sine wave signal is obtained. <IMAGE></p> |
