scholarly journals Noise Modeling and Simulation of Giant Magnetic Impedance (GMI) Magnetic Sensor

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 960
Author(s):  
Fang Jin ◽  
Xin Tu ◽  
JinChao Wang ◽  
Biao Yang ◽  
KaiFeng Dong ◽  
...  

The detection resolution of a giant magneto-impedance (GMI) sensor is mainly limited by its equivalent input magnetic noise. The noise characteristics of a GMI sensor are evaluated by noise modeling and simulation, which can further optimize the circuit design. This paper first analyzes the noise source of the GMI sensor. It discusses the noise model of the circuit, the output sensitivity model and the modeling process of equivalent input magnetic noise. The noise characteristics of three modules that have the greatest impact on the output noise are then simulated. Finally, the simulation results are verified by experiments. By comparing the simulated noise spectrum curve and the experimental noise spectrum curve, it is demonstrated that the preamplifier and the multiplier contribute the most to the output white noise, and the low-pass filter plays a major role in the output 1/f noise. These modules should be given priority in the optimization of the noise of the conditioning circuit. The above results provide technical support for the practical application of low-noise GMI magnetometers.

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4694
Author(s):  
Kyeongsik Nam ◽  
Hyungseup Kim ◽  
Yongsu Kwon ◽  
Gyuri Choi ◽  
Taeyup Kim ◽  
...  

Air flow measurements provide significant information required for understanding the characteristics of insect movement. This study proposes a four-channel low-noise readout integrated circuit (IC) in order to measure air flow (air velocity), which can be beneficial to insect biomimetic robot systems that have been studied recently. Instrumentation amplifiers (IAs) with low-noise characteristics in readout ICs are essential because the air flow of an insect’s movement, which is electrically converted using a microelectromechanical systems (MEMS) sensor, generally produces a small signal. The fundamental architecture employed in the readout IC is a three op amp IA, and it accomplishes low-noise characteristics by chopping. Moreover, the readout IC has a four-channel input structure and implements an automatic offset calibration loop (AOCL) for input offset correction. The AOCL based on the binary search logic adjusts the output offset by controlling the input voltage bias generated by the R-2R digital-to-analog converter (DAC). The electrically converted air flow signal is amplified using a three op amp IA, which is passed through a low-pass filter (LPF) for ripple rejection that is generated by chopping, and converted to a digital code by a 12-bit successive approximation register (SAR) analog-to-digital converter (ADC). Furthermore, the readout IC contains a low-dropout (LDO) regulator that enables the supply voltage to drive digital circuits, and a serial peripheral interface (SPI) for digital communication. The readout IC is designed with a 0.18 μm CMOS process and the current consumption is 1.886 mA at 3.3 V supply voltage. The IC has an active area of 6.78 mm2 and input-referred noise (IRN) characteristics of 95.4 nV/√Hz at 1 Hz.


2015 ◽  
Vol 645-646 ◽  
pp. 1279-1284
Author(s):  
Zhang Zhang ◽  
Zheng Xi Cheng ◽  
Yi Wei Zhuang

A low power low noise CMOS amplifier with integrated filter for neural signal recording is designed and fabricated with CSMC 0.5 μm CMOS process. DC offsets introduced by electrode-tissue interface are rejected through a feedback low-pass filter. The bandwidth of the amplifier is in 3.5Hz-5.5KHz range, and the gain is about 48dB in the midband. AC input differential mode voltage range is 10mV, and DC input differential mode voltage range is 180mV. The amplifier can accommodate 180mV DC offsets drift and 10mV neural spikes. The neural probe array is integrated directly on the surface of the amplifier array chip, and is tested in saline solution, and also is implanted in rats in vivo , the results of the experiments show that the amplifier is suitable for neural signal recording. The power dissipation is about 14μW while consuming 0.16 mm2 of chip area, which satisfies implantable devices requirements.


Author(s):  
Mohamad Khairul bin Mohd Kamel ◽  
Yan Chiew Wong

Harvesting energy from ambient Radio Frequency (RF) source is a great deal toward batteryless Internet of Thing (IoT) System on Chip (SoC) application as green technology has become a future interest. However, the harvested energy is unregulated thus it is highly susceptible to noise and cannot be used efficiently. Therefore, a dedicated low noise and high Power Supply Ripple Rejection (PSRR) of Low Dropout (LDO) voltage regulator are needed in the later stages of system development to supply the desired load voltage. Detailed analysis of the noise and PSRR of an LDO is not sufficient. This work presents a design of LDO to generate a regulated output voltage of 1.8V from 3.3V input supply targeted for 120mA load application. The performance of LDO is evaluated and analyzed. The PSRR and noise in LDO have been investigated by applying a low-pass filter. The proposed design achieves the design specification through the simulation results by obtaining 90.85dB of open-loop gain, 76.39º of phase margin and 63.46dB of PSRR respectively. The post-layout simulation shows degradation of gain and maximum load current due to parasitic issue. The measurement of maximum load regulation is dropped to 96mA compared 140mA from post-layout. The proposed LDO is designed using 180nm Silterra CMOS process technology.


Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1966
Author(s):  
Yiming Han ◽  
Fengjie Wang ◽  
Jiarui Liu ◽  
Zhiyu Wang ◽  
Faxin Yu

To improve the linearity of direct conversion receivers (DCRs), two high-linearity methods for high second-order intercept points (IP2s) and high third-order intercept points (IP3s) are proposed. To improve IP3s, a transconductance equalization technique for a complementary input operational amplifier (OPAMP) is proposed in an active-RC low-pass filter (LPF), while a digital-analog hybrid DC offset calibration (DCOC) method is proposed to improve IP2s. For one thing, the proposed transconductance equalization technique employs a pair of resistors to guarantee high voltage gain for an OPAMP with two-stage Miller topology under a high-input voltage swing to improve linearity with little deterioration of the noise performance. For another, during the DCOC method, the low-noise amplifier is turned off and replaced by an equivalent resistance of the output impedance of the low-noise amplifier to ensure the accuracy and effectiveness of the DCOC method. Fabricated in 40-nm CMOS technology, the receiver with proposed methods can realize a noise figure of 2.6–3.5 dB in the full frequency band, with an OIP3 of 28 dBm, an IM2 more than 70 dBc, and a remaining DC of −53.2 dBm under the total voltage gain of 60 dB.


Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 593
Author(s):  
Hyunki Jung ◽  
Dzuhri Radityo Utomo ◽  
Saebyeok Shin ◽  
Seok-Kyun Han ◽  
Sang-Gug Lee ◽  
...  

A broadband receiver front-end with low noise figure and flat conversion gain response is presented in this paper. The receiver front-end is a part of the broadband spectrum sensing receiver and processes 30–40 GHz of broad input spectrum followed by down-conversion to DC-10 GHz of IF signal. The proposed work is comprised of a low noise amplifier (LNA), on-chip passive Balun, down conversion mixer, and output buffer. To achieve front-end target specification over 10 GHz input bandwidth, the stagger-tuned LNA is employed and the down conversion mixer is loaded with a 3rd-order LC ladder low pass filter. The prototype chip was implemented in 45 nm CMOS technology. The chip achieves 10.3–16.5 dB conversion gain, 5.9 dB integrated NF, and −11 dBm IIP3 from 30 to 40 GHz. The chip is realized within 0.42 mm 2 and consumes 96 mW from a 1.2 V supply.


2018 ◽  
pp. 6-12 ◽  
Author(s):  
R. V. Magerramov

This article describes the method of converting an analog signal into a digital code using a phase locked loop (PLL) circuit. The functional structure of the voltage-to-digital conversion circuit is considered. The application of the principle of phase-locked loop for controlling the duty cycle of the output signal of a phase detector when the voltage at the positive input of the operational amplifier included in the low-pass filter is investigated. In the modern world, analog-to-digital converters (ADCs) are available in almost every electronic device. The application of different ADC architectures is determined by their parameters and features by circuit and technological implementation. The phase-locked loop with a digital part (16-bit counter, storage register and data transfer interface) allows to obtain a precision analog-to-digital converter, based on a relatively simple circuit design, which has high accuracy and low noise level. Negative feedback of the PLL loop makes it possible to level the error of the passive elements of the low-pass filter (LPF) and the voltage controlled oscillator (VCO). The result of this work is an analysis of the ADC characteristics in the technological basis of 250 nm.


2013 ◽  
Vol 734-737 ◽  
pp. 2945-2948
Author(s):  
Ting Ting Liu ◽  
Yong Wu ◽  
Jun Lin

Aiming at the low-frequency performance of the lowfrequency seismic pendulum CMG -3T, we design a data acquisition system can acquire the low-frequency seismic waves, at the same time we accomplish the process of adjusting the CMG-3T. This paper gives designing scheme include the low noise design of the power module, the design of the connector to RS232 which can send command to adjusting the mass of CMG-3T,the design of voltage attenuation network and no-source low-pass filter network of data acquisition system, the last is the design of software for adjusting the CMG-3T.


Author(s):  
Jhinhwan Lee

In order to solve the problems of waveform distortion and signal delay by many physical and electrical systems with linear low-pass transfer characteristics with multiple complex poles, a general digital-signal-processing (DSP)-based method of real-time recovery of the original source waveform from the distorted output waveform is proposed. From the convolution kernel representation of a multiple-pole low-pass transfer function with an arbitrary denominator polynomial with real valued coefficients, it is shown that the source waveform can be accurately recovered in real time using a particular moving average algorithm with real-valued DSP computations only, even though some or all of the poles are complex. The proposed digital signal recovery method is DC-accurate and unaffected by initial conditions, transient signals, and resonant amplitude enhancement. The noise characteristics of the data recovery shows inverse of the low-pass filter characteristics. This method can be applied to most sensors and amplifiers operating close to their frequency response limits or around their resonance frequencies to accurately deconvolute the multiple-pole characteristics and to improve the overall performances of data acquisition systems and digital feedback control systems.


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