PROPUESTA PARA EL DESARROLLO ANALÓGICO DE UN AMPLIFICADOR LOCK-IN( PROPOSAL FOR THE ANALOG DEVELOPMENT OF A LOCK-IN AMPLIFIER)
Resumen
Las técnicas de promediado y filtrado, para recuperar señales inmersas en altos niveles de ruido, repercuten en el ancho de banda efectivo de la señal cuando se busca mantener una relación señal a ruido elevada. En estos casos, un equipo muy apreciado es el Amplificador Lock-in. Los equipos comerciales son costosos y no siempre son accesibles en los laboratorios académicos y de investigación; sin embargo, su principio de funcionamiento es relativamente simple, y su implementación con limitaciones aceptables es factible. En este trabajo se exponen las etapas que conforman un Amplificador Lock in y los elementos necesarios para su desarrollo analógico. Se ofrece un ejemplo de diseño, en donde se determina el valor de los componentes para la implementación de un prototipo. En el documento, se reporta el desempeño del prototipo durante la recuperación de una señal senoidal de 354 μV rms (500 μV pico) contaminada con ruido blanco de 15 mV rms, con lo que se demuestra la viabilidad del circuito.
Palabras Claves: Amplificador Lock-in, Diseño analógico, Relación señal a ruido.
Abstract
Averaging and filtering techniques, to recover signals immersed in high noise levels, impact the effective bandwidth of the signal when trying to maintain a high signal-to-noise ratio. In these cases, a highly appreciated device is the Lock-in Amplifier. Commercial equipment is expensive and not always accessible in academic and research laboratories; however, its operating principle is relatively simple, and its development with acceptable limitations is feasible. This work presents the stages that make up a Lock-in Amplifier and the elements necessary for its analog development. A design example is offered, where the value of the components is determined for the implementation of a prototype. In the document, the prototype performance during the recovery of a 354 μV rms sinusoidal signal (500 μV peak) that as contaminated with 15 mV rms white noise is reported, thus demonstrating the viability of the circuit.
Keywords: Analog Design, Lock-in Amplifier, Prototype, Signal-to-noise ratio.
Texto completo:
PDFReferencias
Aguirre, J., García-Romeo, D., Medrano, N., Calvo, B. Square-signal-based algorithm for analog Lock-in amplifiers. IEEE Transactions on Industrial Electronics, Volume 61, Issue 10, pp. 5590-5598, October 2014.
Bengtsson, L. E. A microcontroller-based lock-in amplifier for sub-milliohm resistance measurements. Review of Scientific Instruments, Volume 83, Issue 7, 7075103, pp. 1-8. July 2012.
Best, R. Phase-Locked loops, 5th edition, USA, McGraw Hill Professional Engineering. June 2003.
Bhagyajyoti, Immanuel, J., Sudheer, L. S., Bhaskar, P., Parvathi, C. S. Review on Lock-in Amplifier. International Journal of Science, Engineering and Technology Research (IJSETR) Volume 1, Issue 5, pp. 40-45. November 2012.
Chen, X., Chang, J., Wang, F., Wang, Z., Wei, W., Liu, Y, Qin, Z. A portable analog Lock-In amplifier for accurate phase measurement and application in high-precision optical oxygen concentration detection. Photonic Sensors, Volume 7, Issue. 1, pp. 27–36, 2017.
De Marcellis, A., Ferri, G., Patrizi, M., Stornelli, V., D’Amico, A., Di Natale, C., Martinelli, E., Alimelli, A., Paolesse, R. An integrated analog lock-in amplifier for low-voltage low-frequency sensor interface. IWASI 2007, 2nd International Workshop on Advances in Sensors and Interface, pp. 1-5, Bari, Italy. June 2007.
De Marcellis, A., Palange, E., Liberatore, N., Mengali, S. Low-cost portable 1 MHz Lock-In amplifier for fast measurements of pulsed signals in sensing applications. IEEE Sensor Letter, Volume1, Issue 4, June 2017.
Dorrington, A. A., Kunnemeyer, R. A simple microcontroller based digital lock-in amplifier for the detection of low-level optical signals. Proceedings First IEEE International Workshop on Electronic Design, Test and Applications 2002, pp. 486-488, Christchurch, New Zealand. August 2002.
Kishore, K, Akbar, S. A. Evolution of Lock-In Amplifier as Portable Sensor Interface Platform: A Review. IEEE Sensors Journal, Volume 20, Issue 18, pp. 10345-10354, September 2020.
Franco, S. Design with operational amplifiers and analog integrated circuits. 4th edition, New York, USA, McGraw-Hill Series in Electrical and Computer Engineering, pp. 678-693. 2015.
Gabal, M., Medrano, N., Calvo, B., Martínez, P. A., Celma, S., Valero, M. R. A complete low voltage analog lock-in amplifier to recover sensor signals buried in noise for embedded applications. Elsevier, Procedia Engineering 5, pp. 74-77. 2010.
Hofmann, M., Bierl, R., Rueck, T. Implementation of a dual-phase lock-in amplifier on a TMS320C5515 digital signal processor. 5th European DSP Education and Research Conference (EDERC), Amsterdam, pp. 20 24. 2012.
Horowitz, P., Hill W. The Art of Electronics, 3rd edition, USA, Cambridge University Press, pp. 955-974. 2015.
Liang, T., Bai, X., Suo, P., Tian, W., Sun, J., Xu, L. Design and comparison of two Lock-In amplifiers using demodulators AD630 and ADA2200, 2023 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), Kuala Lumpur, Malaysia, pp. 01-06, 2023.
Libbrecht, K. G., Black, E. D., Hirata, C. M. A basic lock-in amplifier experiment for the undergraduate laboratory. American Journal of Physics, Volume 71, Issue 11, pp. 1208 1213. November 2003.
Liu, Y. L., Zhang, R. AD630 Lock-in amplifier circuit for weak signal. Advanced materials research, Vols. 482-484, pp. 975-980, 2012.
Scofield, J. H., Frequency‐domain description of a lock‐in amplifier. American Journal of Physics Volume 62, Issue 2, pp. 129-133. February 1994.
URL de la licencia: https://creativecommons.org/licenses/by/3.0/deed.es
Pistas Educativas está bajo la Licencia Creative Commons Atribución 3.0 No portada. 
TECNOLÓGICO NACIONAL DE MÉXICO / INSTITUTO TECNOLÓGICO DE CELAYA
Antonio García Cubas Pte #600 esq. Av. Tecnológico, Celaya, Gto. México
Tel. 461 61 17575 Ext 5450 y 5146
pistaseducativas@itcelaya.edu.mx