基于AVR单片机的数字示波器的设计与实现

发布时间：2018-05-15 22:34

本文选题：数字示波器 + 直接数字式频率合成器　；参考：《武汉工业学院》2012年硕士论文

【摘要】：数字示波器是一种用于观察、测量、分析、记录各种动态信号并可以用图形方式显示的电子仪器。市面上所售的示波器往往价格昂贵，对此本文提出了一种低成本数字示波器的设计方案。文中的内容主要分为两部分：数字示波器的硬件设计和软件设计。硬件电路主要包括信号调理电路、AD采样与FIFO缓冲存储电路、DDS时钟电路、TFT显示器与功能按键电路。系统软件的设计是指对微控制器外围电路中相关器件的控制与驱动，以及对采集到的波形数据的分析与处理。本数字示波器以艾特梅尔公司的AVR单片机为控制核心，AVR是8位的RISC微控制器，它在指令和数据吞吐能力方面比传统的CISC结构要快很多倍。在数字示波器的信号调理电路中，使用了增益可变运算放大器和高精度DAC的结构，即放大倍数由DAC的输出电压控制，而DAC的输出电压由AVR单片机的控制数据决定。这种结构不仅可降低电路功耗而且可以用软件对放大倍数进行调整使得控制更加方便。在数字示波器的采样电路中使用了BB公司的高速AD转换器ADS830E，它的最高工作频率可达60MHz，远高于AVR单片机的工作频率，所以在AD之后加入了高速FIFO缓冲存储器，让其与高速AD同步工作。AD转换器的采样时钟信号由DDS电路生成，DDS即直接数字式频率合成器，其应用简单，无需外接元件，输出频率和相位都可通过软件编程，易于调节。传统示波器一般采用多级门电路对主时钟振荡器进行分频得到所需采样时钟，电路不仅结构复杂而且功耗大，两相比较，DDS具有很大的优势。经过调试，数字示波器最终正常运行。系统带宽达到1MHz，输入信号范围为5m V~160V。实现了采样与波形显示、测量频率和峰值以及FFT频谱分析等功能。
[Abstract]:A digital oscilloscope is an electronic instrument used to observe, measure, analyze, record and display various dynamic signals. The oscilloscopes sold on the market are often expensive. This paper presents a design for low cost digital oscilloscopes.
The contents of the paper are divided into two parts: the hardware design and the software design of the digital oscilloscope. The hardware circuit mainly includes the signal conditioning circuit, the AD sampling and the FIFO buffer storage circuit, the DDS clock circuit, the TFT display and the function key circuit. The system software is designed to control and drive the related devices in the peripheral circuits of the micro controller. And the analysis and processing of the collected waveform data.
The digital oscilloscope is controlled by et Mel's AVR microcontroller, and AVR is a 8 bit RISC microcontroller. It is much faster than the traditional CISC structure in instruction and data throughput. In the signal conditioning circuit of the digital oscilloscope, the gain variable operational amplifier and the high precision DAC structure are used. The output voltage of the DAC is controlled, and the output voltage of the DAC is determined by the control data of the AVR MCU. This structure can not only reduce the power consumption of the circuit, but also make the control more convenient by using the software to adjust the magnification. In the sampling circuit of the digital oscilloscope, the high speed AD converter ADS830E of the BB company is used, and the highest frequency of its working frequency is in the digital oscilloscope. The rate is up to 60MHz, far higher than the working frequency of AVR MCU, so the high-speed FIFO buffer memory is added after AD, so that the sampling clock signal of the.AD converter with high speed AD is generated by DDS circuit, DDS is the direct digital frequency synthesizer, its application is simple, no external connection element is needed, the output frequency and phase can be compiled by software. The traditional oscilloscope usually uses a multistage gate circuit to divide the main clock oscillator into the required sampling clock. The circuit is not only complicated but also has large power consumption. The DDS has a great advantage in two phase comparison.
After debugging, the digital oscilloscope runs normally. The bandwidth of the system reaches 1MHz. The input signal range is 5m V~160V., which realizes the functions of sampling and waveform display, measuring frequency and peak and FFT spectrum analysis.

【学位授予单位】：武汉工业学院
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TM935.37;TP368.1

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