音频放大器低频性能的短纯音信号评测法研究  

Evaluation method of low frequency performance of audio frequency amplifiers by tone burst signals

作　　者：张平柯[1] 

机构地区：[1]湖南第一师范学院数学物理系,湖南长沙410002

出　　处：《中南大学学报（自然科学版）》2008年第5期1068-1074,共7页Journal of Central South University:Science and Technology

基　　金：湖南省教育厅2007年度科学研究项目(07C047)

摘　　要：通过组织试听、构建计算机音频测试系统并借助MAPLE软件,研究前置放大器在配接过程中的低频性能;提出响应系数λ的概念。研究结果表明:由于脉冲状态的信号更接近实际音乐信号,更能反映人耳对音质的感受,用短纯音信号代替连续纯音信号对放大器系统进行客观测量和主观试听,能比较真实地反映其低频性能;前置放大器在与功率放大器配接时,λ既可反映放大器系统对低频短纯音信号的瞬态反应能力,又可反映其对低频连续纯音信号的幅频特性和相频特性,因此,能较全面地表示放大器系统的低频性能;采用直接耦合的前置放大器与直接耦合式功率放大器搭配,λ可趋近于理想值1,因而具有最佳的低频性能。Through organizing human evaluation on trial performances, measuring the audio frequency by a computer system specifically, and doing theoretic analysis with the aid of MAPLE software, the low frequency performance of the preamplifier during the matching course was researched. And concept of response ratio λ was proposed. The results show that the burst signals can be used for the objective and subjective performance evaluation on the amplifier system, it actually reflects the low frequency performance; because the burst signals sound more like actual performance, which can better meet the need of human ears for tune quality, so using tone burst signals can better reflect the actual low frequency performance of amplifier. And the ratio λ can reflect both the amplifier system＇s transient response to low frequency tone burst signals, and the amplitude-frequency and phase-frequency response characteristics of the continuous pure tone signals, and therefore it can comprehensively reflect the performance of the whole amplifier system. When a direct- coupled preamplifier is matched with a direct-coupled power amplifier, the ratio λ approaches 1, which means the best low frequency performance.

关 键 词：连续纯音信号 短纯音信号 放大器 低频性能 

分 类 号：TN722[电子电信—电路与系统]