在一般的 A 类或 B 类放大器中,通过输出器件的静态电流与输出器件和温度传感器之间的温差有关。而温度传感器通常安装在散热器上。由于输出器件至散热器之间的热阻,以及散热器的热容量,在功耗发生突变后,二者之间的温差很大。因此,音...在一般的 A 类或 B 类放大器中,通过输出器件的静态电流与输出器件和温度传感器之间的温差有关。而温度传感器通常安装在散热器上。由于输出器件至散热器之间的热阻,以及散热器的热容量,在功耗发生突变后,二者之间的温差很大。因此,音频放大器的静态电流每次都随音量的变化而改变。静态电流不是最佳,会引起很大的失真,即大家都知道的交越失真运算放大器的设计师有时用一种非线性共模环(即 AB 类控制环)的技术来降低交越失真。但这种技术只适用于集成电路,不适用于分立元件构成的放大器。展开更多
The theories of diagnosing nonlinear analog circuits by means of the transient response testing are studied. Wavelet analysis is made to extract the transient response signature of nonlinear circuits and compress the ...The theories of diagnosing nonlinear analog circuits by means of the transient response testing are studied. Wavelet analysis is made to extract the transient response signature of nonlinear circuits and compress the signature dada. The best wavelet function is selected based on the between-category total scatter of signature. The fault dictionary of nonlinear circuits is constructed based on improved back-propagation(BP) neural network. Experimental results demonstrate that the method proposed has high diagnostic sensitivity and fast fault identification and deducibility.展开更多
文摘在一般的 A 类或 B 类放大器中,通过输出器件的静态电流与输出器件和温度传感器之间的温差有关。而温度传感器通常安装在散热器上。由于输出器件至散热器之间的热阻,以及散热器的热容量,在功耗发生突变后,二者之间的温差很大。因此,音频放大器的静态电流每次都随音量的变化而改变。静态电流不是最佳,会引起很大的失真,即大家都知道的交越失真运算放大器的设计师有时用一种非线性共模环(即 AB 类控制环)的技术来降低交越失真。但这种技术只适用于集成电路,不适用于分立元件构成的放大器。
基金This project was supported by the National Nature Science Foundation of China(60372001)
文摘The theories of diagnosing nonlinear analog circuits by means of the transient response testing are studied. Wavelet analysis is made to extract the transient response signature of nonlinear circuits and compress the signature dada. The best wavelet function is selected based on the between-category total scatter of signature. The fault dictionary of nonlinear circuits is constructed based on improved back-propagation(BP) neural network. Experimental results demonstrate that the method proposed has high diagnostic sensitivity and fast fault identification and deducibility.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60577020 and 60672004, the National High-Tech Research and Development Program of China under Grant No 2007AA01Z270.
