多倍直流偏置电压对碳纳米管薄膜声源的影响

针对碳纳米管薄膜声源系统的输出声信号频率失真问题，提出在交流信号上施加多倍直流偏置电压的方法。从热致发声原理入手，利用碳纳米管薄膜声压理论，分析出增加多倍直流偏置电压后，输出信号中的一倍频与二倍频声压幅值，并探究两者幅值比变化规律。实验结果表明，随着输入频率和直流偏置电压增加，输出声信号中两者幅值之比亦增加，当直流偏置电压是交流电压的两倍后，输出声信号波形与输入电信号近似一致，较好地解决了频率失真问题；同时，输出声压级也有较大幅度提升。

The effect of multiple direct-current bias to the carbon nanotube film sound system

On account of the output signal frequency distortion problem occurs in carbon nanotube film sound source, the method of applying multiple direct-current bias to original alternating current signal is proposed. From the perspective of the thermophone theory, taking the carbon nanotube film sound pressure theory as reference, inferring the theoretical amplitude of the once frequency output signal with the twice when the bias is added and observing the change rule of the ratio; The experiment result shows that the amplitude ratio of the twos in the output sound signal increases with the frequency and the direct-current bias, and when the direct current is two times of the alternating current, the waveform of output sound signal is almost consistent with input electrical signal, which solves the frequency distortion problem well; also, the output sound pressure level has a significant improvement at the same time.