The circuit of Figure 1 produces an accurate variable-frequency sine wave for use as a general-purpose reference signal. It includes an 8th-order elliptic, switched-capacitor lowpass filter (IC3) that is clocked with a 100kHz square wave generated by microcontroller IC2. (Any other convenient squarewave source is also acceptable.) The microcontroller is clocked by a 10MHz oscillator module. A voltage supervisor (IC1) ensures correct operation in the event of a power failure. IC3 sets the filter's cutoff frequency at 1/100 the clock frequency.

翻譯：

該電路 如圖1 產(chǎn)生一個通用的參考信號準確，可變頻率的正弦波使用。 它包括一個8階橢圓形，開關(guān)電容低通濾波器（IC3的），是IC2的時鐘與微控制器為100kHz方波產(chǎn)生的。 （任何其他方便的方波 來源 也是可以接受的。）微控制器是模塊時鐘由10MHz的振蕩器。 一個 電壓 監(jiān)控 （IC1的）確保正確操作停電事件中的一個。 IC3的套/ 100的時鐘頻率濾波器的截止頻率為1，同時保持它們之間的比例為100:1數(shù)字可調(diào)的正弦信號源。