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A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement

In this work, we report on the design of a wide-band digital lock-in amplifier (DLIA) of up to 65 MHz and its application for electrical impedance measurements in microfluidic devices. The DLIA is comprised of several dedicated technologies. First, it features a fully differential analog circuit, wh...

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Detalles Bibliográficos
Autores principales: Huang, Kan, Geng, Yangye, Zhang, Xibin, Chen, Dihu, Cai, Zhigang, Wang, Min, Zhu, Zhen, Wang, Zixin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6719078/
https://www.ncbi.nlm.nih.gov/pubmed/31405249
http://dx.doi.org/10.3390/s19163519
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author Huang, Kan
Geng, Yangye
Zhang, Xibin
Chen, Dihu
Cai, Zhigang
Wang, Min
Zhu, Zhen
Wang, Zixin
author_facet Huang, Kan
Geng, Yangye
Zhang, Xibin
Chen, Dihu
Cai, Zhigang
Wang, Min
Zhu, Zhen
Wang, Zixin
author_sort Huang, Kan
collection PubMed
description In this work, we report on the design of a wide-band digital lock-in amplifier (DLIA) of up to 65 MHz and its application for electrical impedance measurements in microfluidic devices. The DLIA is comprised of several dedicated technologies. First, it features a fully differential analog circuit, which includes a preamplifier with a low input noise of 4.4 nV/√Hz, a programmable-gain amplifier with a gain of 52 dB, and an anti-aliasing, fully differential low-pass filter with −76 dB stop-band attenuation. Second, the DLIA has an all-digital phase lock loop, which features a phase deviation of less than 0.02° throughout the frequency range. The phase lock loop utilizes an equally accurate period-frequency measurement, with a sub-ppm precision of frequency detection. Third, a modified clock link is implemented in the DLIA to improve the signal-to-noise ratio of the analog-to-digital converter affected by clock jitter of up to 20 dBc. A series of measurements were performed to characterize the DLIA, and the results showed an accurate performance. Additionally, impedance measurements of standard-size microparticles were performed by frequency sweep from 300 kHz to 30 MHz, using the DLIA in a microfluidic device. Different diameters of microparticle could be accurately distinguished according to the relative impedance at 2.5 MHz. The results confirm the promising applications of the DLIA in microfluidic electrical impedance measurements.
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spelling pubmed-67190782019-09-10 A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement Huang, Kan Geng, Yangye Zhang, Xibin Chen, Dihu Cai, Zhigang Wang, Min Zhu, Zhen Wang, Zixin Sensors (Basel) Article In this work, we report on the design of a wide-band digital lock-in amplifier (DLIA) of up to 65 MHz and its application for electrical impedance measurements in microfluidic devices. The DLIA is comprised of several dedicated technologies. First, it features a fully differential analog circuit, which includes a preamplifier with a low input noise of 4.4 nV/√Hz, a programmable-gain amplifier with a gain of 52 dB, and an anti-aliasing, fully differential low-pass filter with −76 dB stop-band attenuation. Second, the DLIA has an all-digital phase lock loop, which features a phase deviation of less than 0.02° throughout the frequency range. The phase lock loop utilizes an equally accurate period-frequency measurement, with a sub-ppm precision of frequency detection. Third, a modified clock link is implemented in the DLIA to improve the signal-to-noise ratio of the analog-to-digital converter affected by clock jitter of up to 20 dBc. A series of measurements were performed to characterize the DLIA, and the results showed an accurate performance. Additionally, impedance measurements of standard-size microparticles were performed by frequency sweep from 300 kHz to 30 MHz, using the DLIA in a microfluidic device. Different diameters of microparticle could be accurately distinguished according to the relative impedance at 2.5 MHz. The results confirm the promising applications of the DLIA in microfluidic electrical impedance measurements. MDPI 2019-08-11 /pmc/articles/PMC6719078/ /pubmed/31405249 http://dx.doi.org/10.3390/s19163519 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Huang, Kan
Geng, Yangye
Zhang, Xibin
Chen, Dihu
Cai, Zhigang
Wang, Min
Zhu, Zhen
Wang, Zixin
A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement
title A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement
title_full A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement
title_fullStr A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement
title_full_unstemmed A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement
title_short A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement
title_sort wide-band digital lock-in amplifier and its application in microfluidic impedance measurement
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6719078/
https://www.ncbi.nlm.nih.gov/pubmed/31405249
http://dx.doi.org/10.3390/s19163519
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