宽带放大器

电气自动化论文编号:ZD864    论文字数:9843,页数:22

目 录
1  绪论 1
1.1  引言 2
1.2  放大电路的基本知识 2
1.3  放大电路举例 3
1.3.1  运算放大器 3
1.3.1  同相放大电路 3
1.4  放大器的发展 4
2  宽带放大器简介 5
2.1 宽带放大器的定义 5
2.2 宽带放大器的作用 5
2.3 宽带放大器的可靠性 5
2.4  宽带放大器的指标 6
3  宽带放大器的设计方案 7
3.1  总体设计思路 7
3.2  前级放大电路 7
3.3  后级放大电路 9
3.4 测量有效值 9
3.5 自动增益控制（AGC） 10
3.6 峰值检波电路 10
4  AD603运放性能介绍 12
4.1 AD603的特性 12
4.2 电气性能 13
4.3 AD603注意事项 14
4.4 AD603应用 14
5  系统各模块电路的设计 16
5.1  输入缓冲和增益控制部分 16
5.2  功率放大部分 17
5.3  控制部分 17
5.3  稳压电源部分 18
5.4  抗干扰措施 18
5.5  系统软件设计及流程图 19
总 结 20
致 谢 21
参考文献： 22

摘  要
 本设计由三个模块电路构成:前级放大电路(带AGC部分)、后级放大电路和单片机显示与控制模块。在前级放大电路中,用宽带运算放大器AD603两级级联放大输入信号,输出放大一定倍数的电压,经过后级放大电路达到大于8V的有效值输出。单片机显示、控制和数据处理模块除可以程控调节放大器的增益外,还可以实时显示输出电压有效值。 本设计采用高级压控增益器件,进行合理的级联和阻抗匹配,加入后级负反馈互补输出级,全面提高了增益带宽积和输出电压幅度。应用单片机和数字信号处理技术对增益进行预置和控制,AGC稳定性好,可控范围大。
 整个系统通频带为1KHZ~20MHZ,最小增益0dB,最大增益80dB.增益步进为1dB,60dB以下预置增益与际误差小于0.2dB.不失真输出电压有效值达9.5V,输出4.5V~5.5V时,AGC控制范围为66dB
 
关键词：AD603、宽带放大器、增益、放大、AGC

Abstract
The design of a circuit of three modules: the former level amplifier (with AGC), after-class amplifier and SCM display and control module. First-class amplifier, with broadband operational amplifiers AD603 two cascade to enlarge the input signal and output to enlarge a certain multiple of the voltage, after-class amplifier reached after more than 8 V of the RMS output. SCM, control and data processing module can be programmed in addition to adjusting the gain amplifier, can also display real-time output voltage RMS. The design uses high voltage-controlled gain devices, a reasonable cascade and impedance matching, negative feedback after the entry-level complementary output stage, and comprehensively improve the gain bandwidth product and output voltage range. Application MCU and digital signal processing technology to gain a preset and control, AGC has good stability, controllable range. Band system as a whole for 1 KHZ ~ 20MHZ, the smallest gain of 0 dB, the biggest gain of 80 dB. Stepping gain for the 1 dB, 60dB gain and below preset time when error is less than 0.2 dB. Distortion of the output voltage is not an effective value of 9.5 V, output 4.5 V ~ 5.5V when, AGC control range of 66 dB

Keywords：AD603, broadband amplifiers, gain, zoom, AGC