1、 小信号调频发射机设计与实现小信号调频发射机设计与实现 小信号调频发射机设计与实现 I 摘要 调频发射机作为一种简单的通信工具，由于它不需要中转站和地面交换 机站支持，就可以进行有效的移动通信，因此深受人的欢迎。目前它广泛用 于生产、保安、野外工程等领域的小范围移动通信中。 本次设计的调频发射机是将单片机和调频发射机结合，用单片机PB0， PB1，PB2作为与BH1415F 的通讯端口，通过改变PB0，PB1，PB2传送的 高低电平从而改变BH1415F的发射频率。 同时又用单片机去控制四个数码管 动态的去显示调频发射机所发送的频率。调频发射机主要采用了一片 BH1415F 的芯片。BH141
2、5F具有提高信噪比（S/N）的预加重电路、防止信 号过调的限幅电路、控制信号频率的低通滤波电路（LPF）、产生立体声复 合信号的立体声调制电路、调频发射的锁相环电路（PLL）组成。 关键字关键字：单片机 数字化控制 BH1415F 调频发射 小信号调频发射机设计与实现 II Abstract FM Transmitter as a simple communication tool, because it does not need transit and ground stations to support the switch to mobile communications can be
3、 effective, it was welcomed by the people. It is widely used in current production, security, field engineering and other fields of small-scale mobile communication projects. The FM transmitter is designed microcontroller and FM transmitter combined with MCU PB0, PB1, PB2 and BH1415F as communicatio
4、n ports, by changing the PB0, PB1, PB2 high-low transfer thus changing the transmitting frequency BH1415F. At the same time with the microcontroller to control the dynamics of the four digital FM transmitter to display the transmit frequency. FM transmitters are mainly used a BH1415F chips. BH1415F with improved signal to noise ratio(S/N) of pre-emphasis circuit to prevent clipping the signal overshoot circuit , the control input signal frequency low-pass filter circuit(LPF), generating ster
