基于阻抗控制的甚高频调频接收系统

VHF FM receiving system based on impedance control

设计了一套88~108MHz频率范围的甚高频调频接收系统,覆盖了整个调频广播波段.介绍了系统工作原理,并给出了详细的理论推导过程和完整的实现电路.系统采用超外差式结构,先将甚高频搬移到中频10.7 MHz,然后利用乘积型相位鉴频法进行解调.系统设计过程中,充分考虑了阻抗控制,并通过自动增益控制保证输出音频信号的稳定性.静态实验和动态测试效果表明,系统性能稳定,接收灵敏度高,能够应用于高校实验教学等多种场合.

This paper designed a very high frequency （VHF）-frequency modulation （FM） receiver system with frequency ranges from 88 MHz to 108 MHz, covering the entire FM broadcast band. This paper in- troduces the working principle of the system, and gives a detailed theoretical derivation process and a com- plete realization of the circuit. The system uses a superheterodyne structure to move the first high-frequen- cy to the IF 10.7 MHz, and then using the product phase-frequency demodulation method. In the system designing process, the impedance control is fully considered, and using the automatic gain control to en- sure the stability of the output audio signal. The results of static experiment and dynamic test show that the system has stable performance and high receiving sensitivity, which can be applied to many kinds of oc- casions such as experimental teaching in colleges and universities.