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.

重要的是，使用没有电磁屏蔽的超敏传感器来消除测量中的大型环境噪声。该研究主题旨在通过主动噪声控制（ANC）减少传感器的环境噪声输入。目标频率区域为数百个Hz或更小，MHz区域。在低频率区域，测量系统假定使用超导量子干扰装置（Squid）磁力计作为传感器进行非破坏性测试。使用负反馈回路组成尝试取消噪声。为了防止信号衰减，此反馈回路包含低通滤波器（LPF）。首先，LPF提取了较大的低频噪声。然后，将具有反相分量的信号馈回补偿电路。最后，通过补偿磁场取消磁场。该ANC系统进行了使用机器人臂进行扫描测量，而在没有ANC系统的钢样品的情况下，观察到大噪声。重要的是选择LPF的最佳特征以获得高灵敏度。另一方面，MHz射频区域中的环境噪声试图降低ANC系统的所谓射频干扰（RFI）。首先，已经设计了包括相位和振幅控制电路的ANC系统，以精确调整反相波和MHz区域噪声波的振幅。 ANC系统将这种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的ANC系统的可行性用于高速处理。该ANC系统有效地抑制了MHz正弦波。减少量约为40 dB。