基于电流取样调制的电阻低频噪声测试方法

针对现有电阻低频噪声测试技术的不足,提出了基于直流偏置和电流取样调制的噪声测试新方法。采用跨阻前置放大器对被测电阻噪声电流取样,采用交叉开关对取样的噪声电流进行调制。前置放大器的低频噪声电流和噪声电压不会受到调制,被测电阻低频噪声被调制到较高频率处。采用高通滤波有效抑制放大电路的低频噪声,以便提高放大电路的增益。采用同步相敏检测和低通滤波,进一步抑制放大电路的低频噪声,从而准确地检测被测电阻低频噪声。理论和实验结果表明:所提出的方法能够获得较高的电阻低频噪声测试分辨率,并准确地反映直流偏置下的电阻噪声特性。

A Method for Low Frequency Noise Resistance Detection Based on the Current sampling modulation

To overcome the drawback of the existing resistance low frequency noise testing technology, a new detection method based on DC offset and current sampling modulation technology is proposed. The transimpedance amplifier (TIA) is used to sample the noise current of measured resistance, and the crossbar is used to modulate of the sampled noise current. Low frequency noise current and noise voltage for preamplifier will not be modulated, and the low-frequency noise frequency of the measured resistance will migrate to higher frequencies. In order to improve the gain of the amplifier circuit, high-pass filter are used to effectively achieve low frequency noise performance of amplifier circuit. Based on synchronous phase-sensitive detection and low-pass filter, low frequency noise of amplifier circuit can be further suppressed, so that the low frequency noise of measured resistance can be detected accurately. Theoretical and experimental results have indicated that the proposed method can obtain a higher test resolution of resistance low frequency noise, and can reflect the characteristics of resistor noise under DC bias accurately.