基于AD9914的信号发生器的设计及实现

Design and Implementation of Frequency Synthesizer based on AD9914

针对目前信号源输出波形单一、频率较低的问题,根据直接数字频率合成(DDS)理论的基本原理,利用C8051F500单片机作为控制器件,选用高性能DDS芯片AD9914设计了一款信号发生器。该信号发生器能够输出190~210 MHz以上的信号,并且能够进行FSK、PSK、ASK等调制,而且针对直接频率合成器自身的频率杂散的问题,采用ADS软件设计了一款简单实用的电容耦合谐振式带通滤波器去除杂散,通过对系统的最终测试和实验数据分析表明,该系统稳定性好,具有较高的应用价值。

Aiming at the problem of single output waveform and low frequency of signal source, a signal generator is designed by using C8051 F500 single chip computers as control device and high-performance DDS chip AD9914 according to the basic principle of direct digital frequency synthesis theory. The signal generator can output signals of 190 ~ 210 MHz or more, and perform modulations such as FSK, PSK, and ASK. In addition, aiming at the problem of frequency spurs of the direct frequency synthesizer itself, and with ADS software, a simple and practical capacitively coupled resonant bandpass filter is designed to remove spurs. Final test and analysis on experimental data indicate that this system has good stability and fairly high application value.