Ultra weak signal detection method using active noise control system

利用主动噪声控制系统的超微弱信号检测方法

基本信息

批准号：
17560372
负责人：
SAKUTA Ken
金额：
$ 1.98万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560372/
关键词：
Active noise control magnetic noise radio frequency interference phase control digital signal processing field programmable gate array 電磁波雑音 SQUID

项目摘要

It is important to remove large environmental noise in measurement using hypersensitive sensors without electromagnetic shielding. This research topic has aimed to decrease the environmental noise input to the sensor by active noise control (ANC). The target frequency regions were several hundreds Hz or less and the MHz region.In the low frequency region, the measurement system assumed the nondestructive testing using the superconducting quantum interference device (SQUID) magnetometer as a sensor. The noise cancellation was attempted using the negative feedback loop composition. To prevent the signal from attenuating, this feedback loop contains the low pass filter (LPF). The large low-frequency noise was extracted by the LPF firstly. Then a signal with an antiphase component was fed back to a compensation circuit. Finally, the magnetic field was canceled by the compensation magnetic field. This ANC system made scanning measurement using robot-arms become possible, while the large noise was observed in the case of steel sample without the ANC system. It is important to choose the optimum characteristics of the LPF in order to get high sensitivity of detection.On the other hand, the environmental noise in the MHz radio-frequency region, so-called radio frequency interference (RFI) was attempted to be reduced by the ANC system. Firstly, the ANC system including a phase and amplitude control circuit has been designed to allow precise adjustments of the phase and the amplitude of the anti-phase wave against the noise waves in the MHz region. The ANC system suppressed this sinusoidal wave to the white noise level by about 54 dB. Next, the feasibility of the ANC system for MHz RFI that used the digital signal processing was studied for high speed processing. This ANC system suppressed the MHz sinusoidal waves effectively. The amount of reduction was about 40 dB.

在使用无电磁屏蔽的超灵敏传感器进行测量时消除较大的环境噪声非常重要。本研究课题旨在通过主动噪声控制（ANC）来减少输入到传感器的环境噪声。目标频率区域为数百Hz以下和MHz区域。在低频区域，测量系统假设使用超导量子干涉装置（SQUID）磁力计作为传感器进行无损检测。尝试使用负反馈环路组合来消除噪声。为了防止信号衰减，该反馈环路包含低通滤波器 (LPF)。较大的低频噪声首先由LPF 提取。然后具有反相分量的信号被反馈到补偿电路。最后，通过补偿磁场抵消磁场。该 ANC 系统使使用机械臂进行扫描测量成为可能，而在没有 ANC 系统的钢样品中观察到较大的噪声。为了获得高检测灵敏度，选择 LPF 的最佳特性非常重要。另一方面，人们试图降低 MHz 射频区域的环境噪声，即所谓的射频干扰 (RFI)通过 ANC 系统。首先，ANC系统包括相位和幅度控制电路，其设计允许针对MHz区域的噪声波精确调整反相波的相位和幅度。 ANC 系统将此正弦波抑制至白噪声水平约 54 dB。接下来，研究了使用数字信号处理的 MHz RFI ANC 系统进行高速处理的可行性。该ANC系统有效抑制了MHz正弦波。降低量约为 40 dB。