A phase-lock circuit composed of special phase-lock CMOS chip CD 4046 and frequency dividing chip CD 4040 is designed,with a simple external integral loop filter composed of a resistance and a capacitance.

• 用CMOS专用数字锁相芯片CD4046(内部集成有鉴相器和压控振荡器)和分频芯片CD4040构成了实际锁相电路,外加由电阻和电容形成的简单的片外积分环路滤波器。