摘要
以STM32单片机为任务控制与数据处理核心,根据零中频正交解调原理,进行频率特性测试仪的设计制作。采用直接频率合成芯片AD9854制作扫频信号源,产生I、Q两路正交信号,这两路信号分别通过放大器、模拟乘法器及低通滤波器等外围电路,由STM32的片内ADC进行信号采集,经运算获得被测网络的幅频特性与相频特性。该测试仪可以进行点频测量和1~50MHz的扫频测量,可以手动预置测频范围和步进频率,并在320×240彩色液晶屏上显示幅频特性和相频特性曲线。
Taking STM32 MCU as the task control and data processing center and basing on the zero-IF quadrature demodulation theory,a frequency characteristics tester was designed,in which,the AD9854 direct frequency synthesizer chip generates the sweep frequency signal source and the two orthogonal sine waves（ I and Q） which passing through the amplifier,analog multiplier and the low pass filter till to be collected by ADC in STM32; and through computation,the testing network＇s amplitude-frequency and phase-frequency characteristics can be obtained. The frequency characteristic tester can implement point frequency measurement and1MHz to 50MHz sweep measurement,and its frequency measurement range and stepping frequency can be manually set,as well as the frequency characteristics curves can be displayed on a 320x240 LCD screen.
出处
《化工自动化及仪表》
CAS
2014年第6期655-659,共5页
Control and Instruments in Chemical Industry
基金
国家自然科学基金资助项目(61201419)
