基于单片机的滤波器幅频特性自动测试技术
发布时间：2018-11-27 14:47
【摘要】：幅频特性是一个网络性能最直观的反映,在现代电子测量中占据着重要的地位。本文着重分析了幅频特性测试的工作原理,在对市场上幅频特性测试仪的研究现状进行分析之后,确定了本系统的性能指标和总体设计方案。根据设计方案要求,设计了一种幅频特性自动测试仪。此设计主要有扫频信号发生电路、增益控制电路、信号处理单元、人机接口、GUI用户界面等几部分组成。其中扫频信号发生电路采用低功耗DDS芯片AD9833,产生幅值可调的正弦波。具有频率转换时间快、频率分辨率高、可编程控制等优点。采用基于ARM Cortex-MO的32位微控制器lpclllx系列,实现被测信号的检测。再加上增益控制电路,使这种幅频特性自动测试仪能适应各种测试要求。配有LCD液晶显示,调试方便,性能稳定可靠,能够在全频段范围内自动步进测量,采用按键功能,可预置测量范围及步进频率值,可以更加细致的观察幅频特性图,经测试,该幅频测试仪能够输出有效值可调的正弦波、无明显失真、全频段幅度误差在2%,输出正弦波的频率范围为100HZ-5kHZ,交流信号的测量精度为0.07%、分辨率为0.01V,输出阻抗小于10Ω,输入阻抗大于100k。
[Abstract]:The amplitude-frequency characteristic is the most direct reflection of the network performance and plays an important role in modern electronic measurement. In this paper, the working principle of amplitude-frequency characteristic testing is analyzed. After analyzing the research status of amplitude-frequency characteristic tester in the market, the performance index and overall design scheme of the system are determined. According to the requirements of the design scheme, an automatic measuring instrument for amplitude and frequency characteristics is designed. This design consists of sweep signal generating circuit, gain control circuit, signal processing unit, man-machine interface, GUI user interface and so on. Low power DDS chip AD9833, is used to generate sinusoidal wave with adjustable amplitude. It has the advantages of fast frequency conversion time, high frequency resolution and programmable control. The 32-bit microcontroller lpclllx series based on ARM Cortex-MO is used to detect the measured signal. With the addition of gain control circuit, the automatic testing instrument of amplitude and frequency characteristics can meet various testing requirements. Equipped with LCD liquid crystal display, easy debugging, stable and reliable performance, automatic step measurement in full frequency range, key function, preset measurement range and step frequency value, more meticulous observation amplitude and frequency characteristic diagram, through testing, The amplitude-frequency tester can output sinusoidal wave with adjustable RMS without obvious distortion. The amplitude error of the whole frequency band is 2, the frequency range of output sinusoidal wave is 100HZ-5kHZ, the measuring accuracy of AC signal is 0.07 and the resolution is 0.01V. The output impedance is less than 10 惟 and the input impedance is more than 100k.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TN713;TP368.1
本文编号：2361165
[Abstract]:The amplitude-frequency characteristic is the most direct reflection of the network performance and plays an important role in modern electronic measurement. In this paper, the working principle of amplitude-frequency characteristic testing is analyzed. After analyzing the research status of amplitude-frequency characteristic tester in the market, the performance index and overall design scheme of the system are determined. According to the requirements of the design scheme, an automatic measuring instrument for amplitude and frequency characteristics is designed. This design consists of sweep signal generating circuit, gain control circuit, signal processing unit, man-machine interface, GUI user interface and so on. Low power DDS chip AD9833, is used to generate sinusoidal wave with adjustable amplitude. It has the advantages of fast frequency conversion time, high frequency resolution and programmable control. The 32-bit microcontroller lpclllx series based on ARM Cortex-MO is used to detect the measured signal. With the addition of gain control circuit, the automatic testing instrument of amplitude and frequency characteristics can meet various testing requirements. Equipped with LCD liquid crystal display, easy debugging, stable and reliable performance, automatic step measurement in full frequency range, key function, preset measurement range and step frequency value, more meticulous observation amplitude and frequency characteristic diagram, through testing, The amplitude-frequency tester can output sinusoidal wave with adjustable RMS without obvious distortion. The amplitude error of the whole frequency band is 2, the frequency range of output sinusoidal wave is 100HZ-5kHZ, the measuring accuracy of AC signal is 0.07 and the resolution is 0.01V. The output impedance is less than 10 惟 and the input impedance is more than 100k.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TN713;TP368.1
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