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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| Format: | Article |
| Language: | English |
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MDPI AG
2019-08-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/19/16/3519 |
| _version_ | 1811183957017886720 |
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| author | Kan Huang Yangye Geng Xibin Zhang Dihu Chen Zhigang Cai Min Wang Zhen Zhu Zixin Wang |
| author_facet | Kan Huang Yangye Geng Xibin Zhang Dihu Chen Zhigang Cai Min Wang Zhen Zhu Zixin Wang |
| author_sort | Kan Huang |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-04-11T13:05:25Z |
| format | Article |
| id | doaj.art-dad0018b0ac44271846f38b39a72239c |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-04-11T13:05:25Z |
| publishDate | 2019-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-dad0018b0ac44271846f38b39a72239c2022-12-22T04:22:48ZengMDPI AGSensors1424-82202019-08-011916351910.3390/s19163519s19163519A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance MeasurementKan Huang0Yangye Geng1Xibin Zhang2Dihu Chen3Zhigang Cai4Min Wang5Zhen Zhu6Zixin Wang7School of Electronics and Information Technology, Sun Yat-Sen University, Xingang Xi Road 135, Guangzhou 510275, ChinaKey Laboratory of MEMS of Ministry of Education, School of Electronic Science and Engineering, Southeast University, Sipailou 2, Nanjing 210096, ChinaSchool of Electronics and Information Technology, Sun Yat-Sen University, Xingang Xi Road 135, Guangzhou 510275, ChinaSchool of Electronics and Information Technology, Sun Yat-Sen University, Xingang Xi Road 135, Guangzhou 510275, ChinaSchool of Electronics and Information Technology, Sun Yat-Sen University, Xingang Xi Road 135, Guangzhou 510275, ChinaGuangzhou Institute of Geochemistry, Chinese Academy of Sciences, Kehua Street 511, Guangzhou 510640, ChinaKey Laboratory of MEMS of Ministry of Education, School of Electronic Science and Engineering, Southeast University, Sipailou 2, Nanjing 210096, ChinaSchool of Electronics and Information Technology, Sun Yat-Sen University, Xingang Xi Road 135, Guangzhou 510275, ChinaIn 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.https://www.mdpi.com/1424-8220/19/16/3519digital lock-in amplifierwide-bandfully differential analog circuitreconfigurable hardwareelectrical impedance spectroscopy |
| spellingShingle | Kan Huang Yangye Geng Xibin Zhang Dihu Chen Zhigang Cai Min Wang Zhen Zhu Zixin Wang A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement Sensors digital lock-in amplifier wide-band fully differential analog circuit reconfigurable hardware electrical impedance spectroscopy |
| 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 | digital lock-in amplifier wide-band fully differential analog circuit reconfigurable hardware electrical impedance spectroscopy |
| url | https://www.mdpi.com/1424-8220/19/16/3519 |
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