基于场效应管可变电阻特性的振幅调制及非线性失真矫正

Amplitude Modulation and Nonlinear Distortion Correction Based on Variable Resistance Characteristics of FET

依据场效应管可变电阻特性设计了语音信号的振幅调制(Amplitude Modulation,AM)与传输系统。针对栅源电压与漏源电阻间固有的非线性关系会导致调幅信号非线性失真与调幅度较低的问题,采取了基于单片机动态拟合的非线性矫正方法。结果显示,在栅源输入信号电压1.7 V时,失真度从52%下降至2.8%,在失真度不影响语音信号接收的前提下,调幅度从18%提高到47%。该调幅方法具有结构简单、易于集成和非线性失真小等特点,在通信系统集成与信号高保真传输等领域具有重要应用前景。

The Amplitude Modulation(AM)and transmission system of speech signal is designed according to the variable resistance characteristics of FET.The inherent nonlinear relationship between the gate source voltage and the drain source resistance leads to the nonlinear distortion and low amplitude modulation degree of the amplitude modulation signal.In order to solve this problem,a dynamic fitting method using a single chip computer is adopted to correct the nonlinearity.The results show that the distortion is reduced from 52%to 2.8%when the gate source input signal voltage is 1.7 V,and the amplitude modulation degree is increased from 18%to 47%when the distortion does not affect the speech signal reception.The proposed AM method has the characteristics of simple structure,easy integration,small nonlinear distortion,and has important application prospects in communication system integration and high fidelity signal transmission.