毕业论文--低噪声超低频功率放大器设计.doc

毕业论文 低噪声超低频功率放大器设计 摘要 本文主要描述了一个具有低噪声性能的前置放大器和一个频率范围在0~100Hz的功率放大器的设计，并要求整个电路的放大功率达300W以上。 本文介绍了音响中超低频功率放大器及低噪声前置放大器的基本原理、电路设计等内容。整个电路主要由稳压电源、前置放大器、低通滤波器、功率放大器4 部分构成。稳压电源主要任务是为前置放大器、低通滤波器、功率放大器提供稳定的直流电压。前置放大器主要任务是完成小信号电压放大，同时要求低噪音。低通滤波器主要任务是实现频率的选择。功率放大器的主要任务是实现电压的放大，尽可能高效率地向负载提供足够大的功率。本设计采用集成电路NE5532、UA741及D-200W实现设计要求，并用Multisim软件仿真。设计的电路结构简洁、实用，充分利用了集成功放的优良性能。 实验结果表明该前置放大器及功率放大器等组成的音响系统在带宽、功率、噪声等方面具有较好的指标、较高的实用性，为音响的设计提供了广阔的思路。 关键词： 前置放大器、功率放大器、低通滤波器、低噪声、低频 ABSTRACT This paper mainly describes the design of a preamplifier with low noise performanceand the power amplifier with a frequency range from 0 to 100Hz. And the power of the whole circuit should be 300W above. This paper introduces the basic principles and circuit designs of the super low frequency power amplifier and low noise preamplifier, etc. The entire circuit is composed of 4 parts, namely, power supply, preamplifier, low-pass filter, power amplifier.The power supply provides a stable DC power for preamplifier, low-pass filter and power amplifier. The preamplifier’s main task is to complete the small-signal voltage amplification, and it also requires low noise. The low-pass filter’s main task is to realize the frequency selection. The power amplifiers main task is to realize the voltage amplification and as efficiency as possible to provide a large power to the load. This design uses the integrated circuits NE5532, UA741 and D-200W realize the design requirements, and simulation with Multisim software. The design of the circuit structure which takes full advantage of the excellent performance of the integrated amplifier is simple and practical. The experimental results show that the power amplifier and preamplifier have good index, higher practicability and provide a broad idea for power amplifier design in bandwidth, distortion degree and noise. Keywords: preamplifier, power amplifier, low pass filter, low noise, low frequency 目录 1 绪论 1 1.1 音频功率放大器简介 1 1.2 前置放大器及功率放大器的发展现状 3 1.3 本课题的研究内容及总体设计方案