单工无线呼叫系统

Half-duplex Wireless Calling System

简要介绍由发射电路、接收电路及控制电路组成的设计．发射部分采用实用的晶振稳频调频发射电路,该电路发射距离远,发射频率稳定．接收部分采用TDA7021集成芯片制作调频接收电路,该电路结构合理,音质清晰洪亮、线路稳定可靠．控制部分由单片机、编码芯片、解码芯片组成,实现单寻、群寻等功能,基本能满足设计要求．

This design is composed by the launching circuit, the accepting circuit and the control circuit. Launching part uses the practical crystal oscillator steady frequency modulation frequency launching circuit, This electric circuit launching can range far, the launching frequency is stable. Accepting part uses the TDA7021 integration chip to manufacture frequency modulation accepting circuit, This electric circuit structure is reasonable, the acoustic fidelity is clear, and the line circuit is reliable. The control part is composed by single-chip microcomputer, the coding chip, and the decoding chip. The functions such as single seek, the group seeks and so on can be realized. The basic performance can satisfy the design request.