测量低信噪比电压的数字相敏解调算法及性能分析

The Performance Analysis of Digital Phase Sensitive Detection Algorithm used to Measure Voltage at Low Signal Noise Ratio

本文研究了低信噪比正弦电压幅值及相位测量用的数字相敏解调（ＤＰＳＤ）算法，给出了ＤＰＳＤ算法的主要参数（数据长度、取样频率、Ａ／Ｄ转换器位数）与低信噪比电压测量的性能指标（测量精度、频率分辨力、动态储备及最小可测电压）之间的关系。对纳伏电压的实际测量表明，理论分析与测量结果是一致的。

In this paper, the digital phase sensitive detection (DPSD) algorithm used to measure the amplitude and phase of a sinusoid at low signal noise ratio has been discussed. The relation between the major parameters of DPSD (data length, sampling frequency, the bits of A/D converter) and the algorithm performance (measurement accuracy, frequency resolving power, dynamic reserve and minimum measured voltage) has been introduced. The nV voltage measurement results demonstrate that the theoretical analysis and measurement results are coincidence, which can be used for program design and application of digital phase sensitive detection.