基于AD9833的多通道信号发生器设计

系统以高速微控制器为核心，利用直接数字频率合成（DDS）技术，产生多通道、多类型的单一输出信号（正弦、方波、三角信号及直流），同时可将这些单一信号作为傅立叶级数的各项分量，合成一路任意周期的输出信号。各单一信号频率、幅值、初相位可通过小键盘及LCD设定，DDS芯片产生设定频率和初相位、但幅值固定的输出信号，数字电位器、微控制器片内A／D则实现了信号幅值的闭环调节，极大地降低了幅值误差，实测结果表明该系统输出信号具有较高的精度。

Design of Multi-channel Signal Generator Based on AD9833

The system takes the high-speed microcontroller as the control center.By using the direct digital synthesis(DDS) technology,multi-channel and multi-type single wave outputs can be produced,such as sinusoidal,square,triangular and DC Wave,at the same time,take these outputs as components of Fourier series,incorporated them into one synthesized signal with arbitrary period.The keyboard and the LCD set up the frequency,amplitude and initial phase of all single signals.The DDS chip produced the signal with given frequency and initial phase,but with fixed amplitude.The closed-loop adjust of the signal amplitude was achieved by the digitally controlled potentiometer and the A/D converter in the microcontroller,it reduced amplitude error excessively.The measurement result showed the output waves have high accuracy.