scholarly journals High-Precision Acceleration Measurement System Based on Tunnel Magneto-Resistance Effect

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1117 ◽  
Author(s):  
Lu Gao ◽  
Fang Chen ◽  
Yingfei Yao ◽  
Dacheng Xu
Keyword(s):  
Magnetic Field ◽  
High Precision ◽  
Measurement System ◽  
Frequency Modulation ◽  
High Frequency ◽  
Low Noise ◽  
Acceleration Measurement ◽  
Field Source ◽  
Modulation Technique ◽  
Magneto Resistance

A high-precision acceleration measurement system based on an ultra-sensitive tunnel magneto-resistance (TMR) sensor is presented in this paper. A “force–magnetic–electric” coupling structure that converts an input acceleration into a change in magnetic field around the TMR sensor is designed. In such a structure, a micro-cantilever is integrated with a magnetic field source on its tip. Under an acceleration, the mechanical displacement of the cantilever causes a change in the spatial magnetic field sensed by the TMR sensor. The TMR sensor is constructed with a Wheatstone bridge structure to achieve an enhanced sensitivity. Meanwhile, a low-noise differential circuit is developed for the proposed system to further improve the precision of the measured acceleration. The experimental results show that the micro-system achieves a measurement resolution of 19 μg/√Hz at 1 Hz, a scale factor of 191 mV/g within a range of ± 2 g, and a bias instability of 38 μg (Allan variance). The noise sources of the proposed system are thoroughly investigated, which shows that low-frequency 1/f noise is the dominant noise source. We propose to use a high-frequency modulation technique to suppress the 1/f noise effectively. Measurement results show that the 1/f noise is suppressed about 8.6-fold at 1 Hz and the proposed system resolution can be improved to 2.2 μg/√Hz theoretically with this high-frequency modulation technique.

Study of a closed-loop high-precision front-end circuit for tunneling magneto-resistance sensors

2019 ◽  
Vol 33 (08) ◽  
pp. 1950085 ◽  
Author(s):  
Xiangyu Li ◽  
Jianping Hu ◽  
Xiaowei Liu
Keyword(s):  
High Precision ◽  
Closed Loop ◽  
Low Frequency ◽  
Cmos Technology ◽  
Low Noise ◽  
Corner Frequency ◽  
Cmos Process ◽  
Interface Circuit ◽  
Front End ◽  
Magneto Resistance

A closed-loop high-precision front-end interface circuit in a standard 0.35 [Formula: see text]m CMOS technology for a tunneling magneto-resistance (TMR) sensor is presented in this paper. In consideration of processing a low frequency and weak geomagnetic signal, a low-noise front-end detection circuit is proposed with chopper technique to eliminate the 1/f noise and offset of operational amplifier. A novel ripple suppression loop is proposed for eliminating the ripple in a tunneling magneto-resistance sensor interface circuit. Even harmonics is eliminated by fully differential structure. The interface is fabricated in a standard 0.35 [Formula: see text]m CMOS process and the active circuit area is about [Formula: see text]. The interface chip consumes 7 mW at a 5 V supply and the 1/f noise corner frequency is lower than 1 Hz. The interface circuit of TMR sensors can achieve a better noise level of [Formula: see text]. The ripple can be suppressed to less than 10 [Formula: see text]V by ripple suppression loop.

scholarly journals Low-Noise Chopper-Stabilized Multi-Path Operational Amplifier with Nested Miller Compensation for High-Precision Sensors

2019 ◽  
Vol 10 (1) ◽  
pp. 281 ◽  
Author(s):  
Jaesung Kim ◽  
Hyungseup Kim ◽  
Kwonsang Han ◽  
Donggeun You ◽  
Hyunwoo Heo ◽  
...  
Keyword(s):  
High Precision ◽  
Operational Amplifier ◽  
High Frequency ◽  
Flicker Noise ◽  
Low Frequency ◽  
Low Noise ◽  
Cmos Process ◽  
Miller Compensation ◽  
Chopper Stabilization ◽  
Nested Miller Compensation

This paper presents a low-noise multi-path operational amplifier for high-precision sensors. A chopper stabilization technique is applied to the amplifier to remove offset and flicker noise. A ripple reduction loop (RRL) is designed to remove the ripple generated in the process of up-modulating the flicker noise and offset. To cancel the notch in the overall transfer function due to the RRL operation, a multi-path architecture using both a low-frequency path (LFP) and high-frequency path (HFP) is implemented. The low frequency path amplifier is implemented using the chopper technique and the RRL. In the high-frequency path amplifier, a class-AB output stage is implemented to improve the power efficiency. The transfer functions of the LFP and HFP induce a first-order frequency response in the system through nested Miller compensation. The low-noise multi-path amplifier was fabricated using a 0.18 µm 1P6M complementary metal-oxide-semiconductor (CMOS) process. The power consumption of the proposed low-noise operational amplifier is 0.174 mW with a 1.8 V supply and an active area of 1.18 mm2. The proposed low-noise amplifier has a unit gain bandwidth (UGBW) of 3.16 MHz, an input referred noise of 11.8 nV/√Hz, and a noise efficiency factor (NEF) of 4.46.

New Large-Size Three-Dimensional Optical Measuring System Investigation

2013 ◽  
Vol 552 ◽  
pp. 271-275
Author(s):  
Jin Song Wang ◽  
Jian Liu ◽  
Li Juan Li ◽  
Shan Liu ◽  
Zhi Yong An
Keyword(s):  
Measurement System ◽  
Frequency Modulation ◽  
High Frequency ◽  
Optical Measurement ◽  
Three Dimensional ◽  
Automatic Measurement ◽  
High Accuracy ◽  
Measuring System ◽  
Laser Radar ◽  
Large Size

In this paper a new three-dimensional large-size optical measurement system by laser radar has been proposed in combination of double-optic circuit measuring technology, ultra-high frequency modulation technology and laser intellectual tracing and location technology. The system can measure 3d shape unconnectedly for lager-size object, which has the advantages of high accuracy, automatic measurement and freedom from being influenced by material and light ray.

scholarly journals High-Precision and Low-Cost Wireless 16-Channel Measurement System for Malachite Green Detection

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 646 ◽  
Author(s):  
Tong Shen ◽  
Tong Zhou ◽  
Ying Wan ◽  
Yan Su
Keyword(s):  
Malachite Green ◽  
High Precision ◽  
Measurement System ◽  
Detection System ◽  
Low Cost ◽  
Test Methods ◽  
Low Noise ◽  
Measurement Capability ◽  
Aquatic Product ◽  
Maximum Measurement

Focusing on the issue of the malachite green traditional test methods such as large volume, high cost and high complex, this paper proposed a novel multi-channel electrochemical malachite green detection system. Specific recognition properties of malachite green DNA adapter is employed to realize accurate sensing of concentration of malachite green, which can achieve precise detection of malachite green concentration with low noise and high precision. The maximum measurement capability of multi-channel acquisition system is 16 samples in a batch. According to the experimental results, malachite green could be detected quantitatively in the range from 10−3 μg/mL to 10 μg/mL, which performs well in the test of malachite green residues in aquatic product transportation.

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