Frequency-domain description of a lock-in amplifier

Scofield, John

doi:10.1119/1.17629

Cited by 188 publications

(134 citation statements)

References 0 publications

Supporting

Mentioning

117

Contrasting

Unclassified

Order By: Relevance

“…O amplificador Lock-iné uma excelente ferramenta para medir sinais com pequenas amplitudes em sistemas imersos em ruído [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Neste caso, um Lock-in de 16 bits de resolução recebe um sinal do Chopper como referência e outro sinal do fotodector através do condicionador de sinais.…”

Section: Metodologiaunclassified

Aparato experimental para medidas de atividade óptica da sacarose usando um amplificador Lock-in

Fauth¹,

Batista²

2018

View full text Add to dashboard Cite

Resumo: Este trabalho apresenta a montagem de um polarímetro digital para medidas de atividadeóptica em modo pulsado. Em termos de instrumentação científica, foi desenvolvido um circuito eletrônico para medir a intensidade luminosa usando um fotodetector em conjunto com outros componentesópticos e um amplificador Lock-in. Além disso, um porta amostra foi projetado utilizando uma lente de quartzo acoplada em uma tampa e conectada a um tubo de PVC. O desempenho do sistema de medidasé investigado considerando a resolução e o limite de detecção a partir da determinação da rotaçãoóptica específica da sacarose. Este trabalho foi desenvolvido tendo como base o paradigma open source hardware e, portanto, toda a documentação estará disponível para que possa ser utilizada e aprimorada pela comunidade científica.Palavras chave: AtividadeÓptica, Polarímetro, Lock-in, Open Source Hardware. Abstract:This work presents the assembly of a digital polarimeter for measurements of optical activity in pulsed mode.In terms of scientific instrumentation, an electronic circuit was developed to measure light intensity using a photodetector in conjunction with other optical components and a Lock-in amplifier. In addition, a sample port was designed using a quartz lens attached to a cap and connected to a PVC pipe. The performance of the measurement system is investigated considering the resolution and the limit of detection from the determination of the specific optical rotation of sucrose. This work was developed based on the open source hardware paradigm and, therefore, all the documentation will be available so that it can be used and improved by the scientific community.

show abstract

Section: Metodologiaunclassified

Aparato experimental para medidas de atividade óptica da sacarose usando um amplificador Lock-in

Fauth¹,

Batista²

2018

View full text Add to dashboard Cite

show abstract

“…For a more detailed description of lock-in amplifier work principles we refer, for example, to Ref. [16].…”

Section: Methodsmentioning

confidence: 99%

Development of a Wideband EPR Spectrometer with Microstrip and Loop Antennas

Ponomaryov¹,

Choi²,

Suh³

et al. 2013

Journal of Magnetics

View full text Add to dashboard Cite

We have developed a new non-conventional electron paramagnetic resonance (EPR) spectrometer, in which no resonant cavity was used. We previously demonstrated a wide frequency range operation of an EPR spectrometer using two loop antennas, one for a microwave transmission and the other for signal detection [1]. In contrast to Ref.[1], the utilization of a microstrip antenna as a transmitter enhanced a capability of wide-band operation. The replacement of conventional capacitors with varactor diodes makes resonance condition easily reproducible without any mechanical action during tuning and matching procedure since the capacitance of the diodes is controlled electronically. The operation of the new EPR spectrometer was tested by measuring a signal of 1,1-diphenil-2-picrylhydrazyl (DPPH) sample in the frequency range of 0.8-2.5 GHz.

show abstract

“…The signal to be measured is modulated by a reference frequency. The receiver "locks in" to this frequency thus reducing the effect of ambient noise (Scofield, 1994). This results in detection at very low signal-to-noise ratios.…”

Section: Introductionmentioning

confidence: 99%

A remote-control datalogger for large-scale resistivity surveys and robust processing of its signals using a software lock-in approach

Oppermann¹,

Günther²

2018

Geosci. Instrum. Method. Data Syst.

View full text Add to dashboard Cite

Abstract. We present a new versatile datalogger that can be used for a wide range of possible applications in geosciences. It is adjustable in signal strength and sampling frequency, battery saving and can remotely be controlled over a Global System for Mobile Communication (GSM) connection so that it saves running costs, particularly in monitoring experiments. The internet connection allows for checking functionality, controlling schedules and optimizing pre-amplification. We mainly use it for large-scale electrical resistivity tomography (ERT), where it independently registers voltage time series on three channels, while a square-wave current is injected. For the analysis of this time series we present a new approach that is based on the lock-in (LI) method, mainly known from electronic circuits. The method searches the working point (phase) using three different functions based on a mask signal, and determines the amplitude using a direct current (DC) correlation function. We use synthetic data with different types of noise to compare the new method with existing approaches, i.e. selective stacking and a modified fast Fourier transformation (FFT)-based approach that assumes a 1/f noise characteristics. All methods give comparable results, but the LI is better than the well-established stacking method. The FFT approach can be even better but only if the noise strictly follows the assumed characteristics. If overshoots are present in the data, which is typical in the field, FFT performs worse even with good data, which is why we conclude that the new LI approach is the most robust solution. This is also proved by a field data set from a long 2-D ERT profile.

show abstract

Frequency-domain description of a lock-in amplifier

Cited by 188 publications

References 0 publications

Aparato experimental para medidas de atividade óptica da sacarose usando um amplificador Lock-in

Aparato experimental para medidas de atividade óptica da sacarose usando um amplificador Lock-in

Development of a Wideband EPR Spectrometer with Microstrip and Loop Antennas

A remote-control datalogger for large-scale resistivity surveys and robust processing of its signals using a software lock-in approach

Contact Info

Product

Resources

About