模拟电路的低频噪声检测方法

Electrical noise originates from the inherent disturbance of the internal components of electronic circuits. Low-frequency noise in the circuit refers to the voltage(current) noise which frequencies are below 100KHz, and they are sensitive to the internal defects and decay in circuit, according to the investigations of the statistical analysis reports of the integrated circuit equipment production industry, there is low-frequency noise on varying degrees existing in more than 90% of the Analog Circuit. In the project, low-frequency is adopted to analyze the working status of the analog circuits, En-In noise model equivalent to analog circuit is studied, the theoretical noise spectrum and its tolerance threshold is calculated, large-scale network tearing algorithm is used to decompose the circuit, Cross spectrum measurement method is adopted to test and analysis the noise spectrum of sub-circuit, and the method of anti-interference of the test system had been taken into research.Then the methods of weak signal detection are used to effectively extract low-frequency noise from the circuit noise spectrum , and compare the results with the theoretical noise spectrum to determine whether the results exceed the tolerance threshold, analyze the working state of the analog circuit based on low frequency noise. The project is to make a major breakthrough in the field of detections of the low-frequency noise in the circuit, and to provide effective processes to diagnose and predict circuit faults.

电噪声起源于电子线路内部元器件的内在固有扰动。电路中低频噪声是指频率低于100KHz的电压（电流）噪声，它对电路内部的的缺陷和衰变很敏感，近年来集成电路生产设备行业统计分析报告的调查研究发现，90%以上的模拟电路中都存在不同程度的低频噪声。本项目应用低频噪声来分析模拟电路的工作状态，研究模拟电路等效En-In噪声模型，计算理论噪声谱和其容差阈值，运用大规模网络撕裂算法将电路分解，采用互谱测量法测试分析子电路噪声谱，研究测试系统的抗干扰方法。利用微弱信号检测方法从电路噪声谱中有效提取低频噪声，将其与理论噪声谱比较，判定是否超出容差阈值，分析了基于低频噪声的模拟电路电路工作状态，力争在电路低频噪声检测领域取得重大突破，为电路故障诊断和预测提供新的有效途径。

电噪声起源于电子线路内部半导体元件的固有扰动，它对电路内部的缺陷和衰变很敏感，近年来集成电路设备行业统计分析调查报告研究发现，模拟电路在不同程度上都存在低频噪声。由于模拟电路是由多个元器件互连的复杂系统，且对复合低频噪声进行分析也有难度，通过对模拟电路噪声进行分析来判断其工作状态的系统在国内外还未曾见到过。基于此，项目应用低频噪声来分析模拟电路的工作状态，研究了模拟电路等效En-In噪声模型。运用大规模电路网络撕裂算法分解模拟电路，将大规模模拟电路分解为若干个小规模的子电路，单独分析、测量这些小规模子电路的噪声谱，从而减少了计算与测量的复杂程度。使用分立器件设计放大器前置偏置电路，采用噪声匹配变压器法在降低放大器背景噪声的同时，设计了可以测量nV级低频低噪声的放大器。采集半导体器件和模拟电路的低频噪声，采用双通道互谱分析法及EMD，LMS等算法分析采集得到的半导体器件的RTS噪声，散粒噪声， 噪声、 噪声、爆裂噪声及电路噪声谱，利用谱密度与频率有关的特性，分析测量得到复合噪声中各种低频噪声所占比例及相关参数，并与正常噪声谱进行比较来判断其是处于正常工作状态、故障状态、还是潜在故障状态。设计了放置待测器件和放大电路的高导电导磁材料屏蔽模块，以增强噪声信号对空间电场的抵抗力，防止测试时发生噪声信号漂移严重和无法稳定的问题。.项目通过对模拟电路低频噪声的综合分析与探讨，可以实现对模拟电路及器件的工作状态进行无创、准确地诊断；对于航空航天、精密仪器制造等这些对故障要求极低的领域，此项研究有着广泛的应用前景。