基于cpld的可编程宽带放大器的设计.doc

基于CPLD的可编程宽带放大器的设计

摘要：本设计以AT89C51单片机和CPLD为控制核心，利用高速可编程增益放大器THS7001和可变增益放大器AD603，设计了一种抗噪声能力强、具有自动增益控制且增益范围较宽的可编程宽带放大器。其中AT89C51单片机主要完成读取键值、控制增益和显示功能；而CPLD则作为总线控制器，控制键盘、液晶和A/D转换器与AT89C51单片机之间的数据交换；此外，可控增益放大器以高速可编程增益放大器THS7001和可变增益放大器AD603为核心，AT89C51单片机控制高速可编程增益放大器THS7001实现增益粗调，并通过D/A转换控制可变增益放大器AD603实现增益细调，从而使总增益能够在一个比较理想的宽频带范围内线性变化。

关键词：放大器；宽带；可编程；可变增益；抗噪声；自动增益

Design of a programmable wideband amplifier at the base of CPLD

Abstract: Taking AT89C51 microcontroller and CPLD as the controlling core, and using the high speed programmable-gain amplifier THS7001 and the variable-gain amplifier AD603, the paper designs one kind of programmable wideband amplifier, which has strong anti-noise ability and automatic-gain control and also increases the scope the of automatic-gain wide. During the paper, AT89C51 microcontroller mainly reads the key value and controllers gain and function of the display. At the same time, as the controller of the bus, CPLD controls the data exchange between the keyboard, the liquid crystal or the A/D converter and AT89C51 microcontroller. In addition, the high speed programmable-gain amplifier THS7001 and the variable-gain amplifier AD603 is the core of controlled-gain amplifier. AT89C51 microcontroller controls the high speed programmable-gain amplifier THS7001 to change at a large scope of gain and through D/A converter controls the variable-gain amplifier to change at a small scope of gain. Thus, it is able that the overall gain has a linear variation at a quite ideal scope of wideband.
Key words: amplifier; wideband; programmable-gain; variable-gain; anti-noise; automatic-gain

目    录
摘要……………………………………………………………………………………………1
1 引言 3
2 系统总体方案设计 4
3 系统芯片的选择及分析 5
3.1 系统输入级芯片的选择 5
3.2 系统输出级芯片的选择 6
3.3 增益控制芯片的选择 6
3.3.1 AD603的简介及选用分析 6
3.3.2 THS7001的简介及选用分析 7
3.4 系统增益分析 7
4 提高系统抗噪声性能的措施 7
5 系统硬件电路设计 8
5.1 增益控制电路设计 8
5.2 峰值检波电路设计 9
6 系统软件设计 10
6.1 系统程序总体设计 10
6.2 CPLD程序设计 11
6.3 单片机程序设计 12
结束语 14
参考文献……………………………………………………………………………………14