基于分辨率可调的频谱分析仪设计

Design of spectrum analyzer based on adjustable resolution

综合运用多种现代集成器件,采用外差原理设计了分辨率可调的频谱分析仪。为使频谱仪工作于最佳工作状态,提出了滤波带宽和扫频步进频率同步调节的控制技术。SPCE061A单片机通过给AD9850DDS芯片输送控制字,控制其生成步进频率可调的本机振荡信号,经过AD835集成混频器与输入信号混频,由窄带滤波器MAX297滤波取出差频,送入检波电路得到各频率分量有效值。频率测量范围变宽,为0.1 Hz～40MHz;频率分辨率得到提高,10Hz～100KHz7档可调,使每次测试效果最佳;同步调节使操作更简明。

Using the principle of heterodyne,a new design of spectrum analyzer with adjustable resolution is proposed.To make the spectrum analyzer works in the best working conditions,filter bandwidth and stepped-frequency of sweep-frequency is adjusted synchronously.SPCE061A,through AD9850DDS,controls and generates local oscillator signal with tunable stepped-frequency. Because of new design,range of frequency measurement becomes wider,from 0.1Hz to 40MHz,and frequency resolution is improved.Also,the operation for synchronization adjustment is more concise.