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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.
A VHF FM receiving system with a frequency range from 88 MHz to 108 MHz is designed to cover the entire FM broadcast band.The working principle of the system is introduced and a detailed theoretical derivation process and a complete implementation circuit are given.The system uses superheterodyne Type structure, the first high-frequency moving to 10.7 MHz IF, and then use the product-phase phase frequency demodulation demodulation system design process, full account of the impedance control, and through the automatic gain control to ensure the stability of the output audio signal. Static experiments and dynamic test results show that the system has stable performance and high receiving sensitivity and can be used in many occasions such as experimental teaching in colleges and universities.