A portable low noise low frequency three-axis search coil magnetometer

1980 ◽  
Vol 16 (5) ◽  
pp. 761-763 ◽  
Author(s):  
S. Macintyre
Keyword(s):  
Low Frequency ◽  
Low Noise ◽  
Search Coil

Fluxgate and Search Coil Hybrid: A Low-Noise Wide-Band Magnetometer

2012 ◽  
Vol 48 (11) ◽  
pp. 3700-3703 ◽  
Author(s):  
Feng Han ◽  
Shoumu Harada ◽  
Ichiro Sasada
Keyword(s):  
Wide Band ◽  
Low Noise ◽  
Search Coil

scholarly journals A Low-Power Opamp-Less Second-Order Delta-Sigma Modulator for Bioelectrical Signals in 0.18 µm CMOS

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6456
Author(s):  
Fernando Cardes ◽  
Nikhita Baladari ◽  
Jihyun Lee ◽  
Andreas Hierlemann
Keyword(s):  
Low Power ◽  
Low Frequency ◽  
Cmos Technology ◽  
Low Noise ◽  
Second Order ◽  
Frequency Noise ◽  
Voltage Controlled Oscillator ◽  
Noise Shaping ◽  
Delta Sigma Modulator ◽  
Delta Sigma

This article reports on a compact and low-power CMOS readout circuit for bioelectrical signals based on a second-order delta-sigma modulator. The converter uses a voltage-controlled, oscillator-based quantizer, achieving second-order noise shaping with a single opamp-less integrator and minimal analog circuitry. A prototype has been implemented using 0.18 μm CMOS technology and includes two different variants of the same modulator topology. The main modulator has been optimized for low-noise, neural-action-potential detection in the 300 Hz–6 kHz band, with an input-referred noise of 5.0 μVrms, and occupies an area of 0.0045 mm2. An alternative configuration features a larger input stage to reduce low-frequency noise, achieving 8.7 μVrms in the 1 Hz–10 kHz band, and occupies an area of 0.006 mm2. The modulator is powered at 1.8 V with an estimated power consumption of 3.5 μW.

EXPERIMENTAL INVESTIGATION OF TURBULENCE EFFECTS ON AERODYNAMICS NOISE OF CHANNELED NACA 0012 AIRFOIL

2021 ◽  
pp. 1-6
Author(s):  
Hussein Mohammad ◽  
Latif Ibraheem ◽  
Viktor Kilchyk ◽  
S. O. Bade Shrestha
Keyword(s):  
Wind Turbines ◽  
Low Frequency ◽  
Clean Energy ◽  
Low Noise ◽  
Aerodynamic Noise ◽  
Continuous Exposure ◽  
Residential Housing ◽  
Technology Advancement ◽  
Turbulence Effects ◽  
Noise Measurements

Abstract Wind power is rapidly growing worldwide as a renewable and clean energy of choice due to its competitiveness in cost and technology advancement. However, as the wind turbines grow, the aerodynamic noise generated from the rotating blades is becoming a major concern that limits the use of wind turbines, especially near residential housing areas. A significant low sleep quality has been reported within 2km of wind turbines locations that is becoming a problem for wider use of wind energy. [1]. Generally, continuous exposure to 85-90 dBA noise causes permanent hearing loss to human [2]. To reduce the aerodynamic noise, channeled blades were implemented in this work to damp the airflow turbulence that causes the aerodynamic noise. Samples of different diameter sizes and angle of inclinations with respect to the cord have been tested and compared to a regular unchanneled blade. Noise measurements have been carried out using low-frequency microphones with frequencies ranging between 0-10000 Hz. While turbulence measurements were performed using a hot-wire anemometer. The measured noise around the blades ranged between 20-70 dB up to 600 Hz has proven to be directly related to turbulence intensity. The best low noise blade design was recommended based on noise measurement.

scholarly journals Low-Frequency Noise Evaluation on a Commercial Magnetoimpedance Sensor at Submillihertz Frequencies for Space Magnetic Field Detection

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4888
Author(s):  
Tao Wang ◽  
Chen Kang ◽  
Guozhi Chai
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
Temperature Stability ◽  
Space Missions ◽  
Low Noise ◽  
Integration Time ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Field Detection ◽  
Measurement Limit

The purpose of this study was to measure the low-frequency noise and basic performance of a commercial magnetoimpedance (MI) sensor at sub-millihertz frequencies for use in space missions. Normally, space missions require measuring very weak magnetic fields with a long integration time, such as the space gravitational wave detection mission requiring sub-millihertz frequencies. We set up a platform for measuring the performance on this MI sensor, including low-frequency noise, measurement limit, linearity, and temperature stability. The results show that the low-frequency noise of the MI sensor is below 10 nT/√Hz at 1 mHz and below 100 nT/√Hz at 0.1 mHz; its measurement limit is 600 pT. The MI sensor is characterized by high precision, small size, and low noise, demonstrating considerable potential for application in magnetically sensitive experiments requiring long integration time. This is an effect way to solve the problem that there is on one suitable magnetic sensor at space magnetic field detection, but the sensor requires improvements in temperature stability.

scholarly journals Low-Frequency Noise and Microplasma Analysis for c-Si Solar Cell Characterization

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Jiří Vanek ◽  
Jan Dolensky ◽  
Zdenek Chobola ◽  
Mirek Luňák ◽  
Aleš Poruba
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Conversion Efficiency ◽  
Low Frequency ◽  
Low Noise ◽  
Frequency Noise ◽  
Noise Spectral Density ◽  
Selective Emitter ◽  
Noise Spectroscopy ◽  
Cell Conversion

This paper brings the comparison of solar cell conversion efficiency and results from a noise spectroscopy and microplasma presence to evaluate the solar cell technology. Three sets of monocrystalline silicon solar cells (c-Si) varying in front side phosphorus doped emitters were produced by standard screen-printing technique. From the measurements it follows that the noise spectral density related to defects is of 1/ftype and its magnitude. It has been established that samples showing low noise feature high-conversion efficiency. The best results were reached for a group solar cells with selective emitter structure prepared by double-phosphorus diffusion process.

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