基于锁相环载波数字可调的调频收发系统

Frequency-modulated Transceiver System Based on Phase-locked Loop and Digital Adjustable Carrier

基于锁相环技术的调频收发系统,相比传统锁相环调频,采用数字偏置控制压控振荡器实现载波数字可调。其中调制部分仅借助锁相环CD74HC7046片内压控振荡器,由微处理器ADC产生偏置信号,以调节VCO输出信号中心频率,且中心频率在30~38.61 MHz内数字可调;解调部分则由模拟锁相环解调输出信号。利用Simulink搭建模型进行电路仿真,频谱稳定在中心频率,无其他频段分量,解调信号无失真,效果良好。实验测试中,可无失真传输频率不大于20 kHz的信号,传输距离可达20 m以上,发射系统总功率在50~90 mW之间,传输稳定,效果良好。

The frequency modulation transceiver system based on phase-locked loop technology uses digital bias control voltage controlled oscillator to realize carrier digital adjustment compared with traditional phase-locked loop frequency modulation.The modulation part only uses the phase-locked loop CD74 HC7046 on-chip voltage-controlled oscillator,and the microprocessor ADC generates a bias signal to adjust the center frequency of the VCO output signal,and the center frequency is digitally adjustable from 30 MHz to 38.61 MHz;for the demodulation part,the output signal is then demodulated by an analog phase locked loop.Using Simulink to build the model for circuit simulation,the spectrum is stable at the center frequency,without other frequency band components,and the demodulated signal has no distortion,and the effect is good.In the experimental test,the signal with a transmission frequency of no more than 20 kHz can be transmitted without distortion,and the transmission distance can reach more than 20 m.The total power of the transmitting system is between 50 mW and 90 mW,and the transmission is stable and the effect is good.