High-Performance Analog Front-End (AFE) for EOG Systems

Electrooculography is a technique for measuring the corneo-retinal standing potential of the human eye. The resulting signal is called the electrooculogram (EOG). The primary applications are in ophthalmological diagnosis and in recording eye movements to develop simple human–machine interfaces (HCI). The electronic circuits for EOG signal conditioning are well known in the field of electronic instrumentation; however, the specific characteristics of the EOG signal make a careful electronic design necessary. This work is devoted to presenting the most important issues related to the design of an EOG analog front-end (AFE). In this respect, it is essential to analyze the possible sources of noise, interference, and motion artifacts and how to minimize their effects. Considering these issues, the complete design of an AFE for EOG systems is reported in this work.

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Design of Analog Front-end Circuit for Audio-frequency Magnetotelluric Instrument

Journal of Environmental and Engineering Geophysics ◽

10.2113/jeeg23.3.305 ◽

2018 ◽

Vol 23 (3) ◽

pp. 305-318

Author(s):

Yinglu Zhang ◽

Zhenzhu Xi ◽

Xingpeng Chen ◽

Honglan Wei ◽

Long Huang ◽

...

Keyword(s):

Electric Field ◽

High Performance ◽

Notch Filter ◽

Noise Levels ◽

High Quality ◽

Pass Filter ◽

Input Noise ◽

Front End ◽

Analog Front End ◽

Power Frequency

High-performance audio-frequency magnetotelluric (AMT) instrument is one means of obtaining high-quality electromagnetic (EM) data. To improve the ability of AMT system to obtain high-quality data, this paper presents a design for a high-performance analog front-end circuit for AMT instrument. It mainly consists of the input protection, preamplifier, passive high pass filter, power frequency notch filter, programmable amplifier, and active low pass filter. In addition, this paper proposes a design of low-noise, high-performance preamplifier, which improves the common-mode rejection ratio (CMRR) of analog front-end circuit and effectively enhances the signal-to-noise ratio (SNR) of the circuit. The front-end circuit utilized two-stage twin-T notch filter to effectively suppress the strong interference of fundamental component of power frequency. Also, it used signal relays to control circuit gain and selection of cutoff frequency of anti-aliasing filter, resulting in the improvement of the capability of the analog-to-digital Converter (ADC) to distinguish weak EM signal. The measured results of the electric field and magnetic field channel showed that: 1) The circuit works in frequency range of 1 Hz∼100 kHz; 2) The CMRR values of the preamplifier of electric field channel at low frequencies (1 Hz∼1 kHz) are 111 dB and 97 dB when the gains are 20 dB and 6 dB respectively; 3) The maximum attenuation fundamental power frequency can reach −39.46 dB and −39.04 dB respectively; 4) The total harmonic distortion rate at 1 kHz is 0.022% and 0.029% respectively; 5) The input noise levels of electric field channel are 12.67nV / [Formula: see text] @10Hz and 8.15V / [Formula: see text] @1kHz, while the input noise levels of magnetic field channel are 8.97nV / [Formula: see text] @10Hz and 6.16V / [Formula: see text] @1kHz; and 6) In conclusion, the analog front-end circuit is superior to meet the requirements of the AMT methods, and provides a useful reference for the development of AMT instrument.

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A Design of a High-Performance Analog Front-End for Passive UHF RFID Tag EPC C1G2

Journal of Communications Software and Systems ◽

10.24138/jcomss.v14i2.464 ◽

2018 ◽

Vol 14 (2) ◽

Author(s):

Smail Hassouni ◽

Hassan Qjidaa

Keyword(s):

High Performance ◽

Uhf Rfid ◽

Rfid Tag ◽

Passive Uhf Rfid ◽

Front End ◽

Analog Front End

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The Development of 12 channel ECG Measurement and Arrhythmia Discrimination System with High Performance Medical Analog Front-End(AFE)

Journal of the Korea Academia-Industrial cooperation Society ◽

10.5762/kais.2014.15.4.2217 ◽

2014 ◽

Vol 15 (4) ◽

pp. 2217-2224

Author(s):

Hyun-Chul Ko ◽

SeungHwan Lee ◽

JungHyun Heo ◽

Jeong-Jick Lee ◽

Woo-Hyuk Choi ◽

...

Keyword(s):

High Performance ◽

Front End ◽

Analog Front End

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A Compact High-Performance Programmable-Gain Analog Front End for HomePlug AV2 Communication in 0.18- $\mu \text{m}$ CMOS

IEEE Transactions on Circuits and Systems I Regular Papers ◽

10.1109/tcsi.2017.2707638 ◽

2017 ◽

Vol 64 (11) ◽

pp. 2858-2870

Author(s):

Zhangming Zhu ◽

Jingyu Wang

Keyword(s):

High Performance ◽

Front End ◽

Analog Front End ◽

Programmable Gain

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Coping with Motion Artifacts by Analog Front-End ECG Microchips under Variable Digital Resolution and Gain

Engineering Proceedings ◽

10.3390/ecsa-7-08247 ◽

2020 ◽

Vol 2 (1) ◽

pp. 12

Author(s):

Daniel Cuevas-González ◽

Miguel Bravo-Zanoguera ◽

Eladio Altamira-Colado ◽

Roberto López-Avitia ◽

Juan Pablo García-Vázquez ◽

...

Keyword(s):

Integrated Circuits ◽

Mobile Health ◽

Motion Artifact ◽

Motion Artifacts ◽

Analog To Digital ◽

Cardiac Monitor ◽

Front End ◽

Analog Front End ◽

Amplitude Resolution ◽

Digital Resolution

The development of portable ECG technology has found growing markets, from wearable ECG sensors to ambulatory ECG recorders, encountering challenges of moderately complex to tightly regulated devices. This study investigated how a typical 0.5–40 Hz bandwidth ECG is affected by motion artifact when using analog front-end (AFE) integrated circuits such as the AD823X family. It is known that the typical amplitude resolution of current mobile health ECG devices is 10–12 bits, and sometimes 16-bits, which is enough for monitoring but might be insufficient to identify the small potential amplitudes useful in diagnoses. The interest now is on the interplay of how a digital resolution choice and variable gain can cope with motion artifacts inherent in mobile health devices. With our methodology for a rapid prototyping of an ECG device, and using the AFE AD8232 and Bluetooth communication, a specific cardiac monitor ECG configuration was evaluated under two microcontroller systems of different resolution: a generic Arduino Nano board which featured a 10-bit analog-to-digital converter (ADC) and the 24-bit ADC of Silicon Labs C8051F350 board. The ECG cardiac monitor setup, recommended by Analog Devices, featuring two gain values under these two different microcontroller systems, was explored as to its ability to solve motion artifact problems.

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