本实验要求使用PIC16F877A的CCP1模块的PWM功能和一个一阶RC低通滤波器产生一个5Hz的正弦信号。要求用示波器观察产生正弦信号的频率为准确的5Hz,且没有明显的失真。没有条件的读者可以通过观测直接和CCP1输出引脚相连的LED的闪烁频率来确定产生正弦信号的频率。-PWM function of the requirements of the experimental use PIC16F877A CCP1 module and a first-order RC low-pass filter to produce a 5Hz sinusoidal signals. The observation frequency sinusoidal signal with an oscilloscope for accurate 5Hz, and no obvious distortion. Readers without conditions by observing directly and CCP1 output pin connected to the LED flashing frequency to determine the frequency of the sinusoidal signal.