Lock-in amplifier error prediction and correction in frequency sweep measurements

2007 ◽  
Vol 78 (1) ◽  
pp. 014701 ◽  
Author(s):  
Maximiliano Osvaldo Sonnaillon ◽  
Fabian Jose Bonetto
Keyword(s):  
Error Prediction ◽  
Frequency Sweep ◽  
Lock In

scholarly journals Laser Photothermoacoustic Heterodyned Lock-in Depth Profilometry in Turbid Tissue Phantoms

2021 ◽  
Author(s):  
Ying Fang ◽  
Andreas Mandelis ◽  
Gloria Spirou ◽  
I. Alex Vitkin ◽  
William M. Whelan
Keyword(s):  
Frequency Domain ◽  
Delay Time ◽  
Turbid Media ◽  
Laser Source ◽  
Depth Information ◽  
Chirp Signal ◽  
Sweep Method ◽  
Frequency Sweep ◽  
Linear Frequency ◽  
Lock In

Frequency-domain correlation and spectral analysis photothermoacoustic FD-PTA imaging is a promisingnew technique, which is being developed to detect tumor masses in turbid biological tissue. Unlike conventional biomedical photoacoustics which uses time-of-flight acoustic information induced by a pulsed laser to indicate the tumor size and location, in this research, a new FD-PTA instrument featuring frequency sweep chirp and heterodyne modulation and lock-in detection of a continuous-wave laser source at 1064 nm wavelength is constructed and tested for its depth profilometric capabilities with regard to turbid media imaging. Owing to the linear relationship between the depth of acoustic signal generation and the delay time of signal arrival to the transducer, information specific to a particular depth can be associated with a particular frequency in the chirp signal. Scanning laser-fluence modulation frequencies with a linear frequency sweep method preserves the depth-to-delay time linearity and recovers FD-PTA signals from a range of depths. Combining with the depth information carried by the back-propagated acoustic chirp signal at each scanning position, one could rapidly generate subsurface three-dimensional images of the scanning area at optimal signal-to-noise ratios and low laser fluences, a combination of tasks that is difficult or impossible by use of pulsed photoacoustic detection. In this paper, results of PTA scans performed on tissue mimicking control phantoms with various optical, acoustical, and geometrical properties are presented. A mathematical model is developed to study the laser-induced photothermoacoustic waves in turbid media. The model includes both the scattering and absorption properties of the turbid medium. A good agreement is obtained between the experimental and numerical results. It is concluded that frequency domain photothermoacoustics using a linear frequency sweep method and heterodyne lock-in detection has the potential to be a reliable tool for biomedical depth-profilometric imaging.

scholarly journals Laser Photothermoacoustic Heterodyned Lock-in Depth Profilometry in Turbid Tissue Phantoms

2021 ◽  
Author(s):  
Ying Fang ◽  
Andreas Mandelis ◽  
Gloria Spirou ◽  
I. Alex Vitkin ◽  
William M. Whelan
Keyword(s):  
Frequency Domain ◽  
Delay Time ◽  
Turbid Media ◽  
Laser Source ◽  
Depth Information ◽  
Chirp Signal ◽  
Sweep Method ◽  
Frequency Sweep ◽  
Linear Frequency ◽  
Lock In

Frequency-domain correlation and spectral analysis photothermoacoustic FD-PTA imaging is a promisingnew technique, which is being developed to detect tumor masses in turbid biological tissue. Unlike conventional biomedical photoacoustics which uses time-of-flight acoustic information induced by a pulsed laser to indicate the tumor size and location, in this research, a new FD-PTA instrument featuring frequency sweep chirp and heterodyne modulation and lock-in detection of a continuous-wave laser source at 1064 nm wavelength is constructed and tested for its depth profilometric capabilities with regard to turbid media imaging. Owing to the linear relationship between the depth of acoustic signal generation and the delay time of signal arrival to the transducer, information specific to a particular depth can be associated with a particular frequency in the chirp signal. Scanning laser-fluence modulation frequencies with a linear frequency sweep method preserves the depth-to-delay time linearity and recovers FD-PTA signals from a range of depths. Combining with the depth information carried by the back-propagated acoustic chirp signal at each scanning position, one could rapidly generate subsurface three-dimensional images of the scanning area at optimal signal-to-noise ratios and low laser fluences, a combination of tasks that is difficult or impossible by use of pulsed photoacoustic detection. In this paper, results of PTA scans performed on tissue mimicking control phantoms with various optical, acoustical, and geometrical properties are presented. A mathematical model is developed to study the laser-induced photothermoacoustic waves in turbid media. The model includes both the scattering and absorption properties of the turbid medium. A good agreement is obtained between the experimental and numerical results. It is concluded that frequency domain photothermoacoustics using a linear frequency sweep method and heterodyne lock-in detection has the potential to be a reliable tool for biomedical depth-profilometric imaging.

Amplitude-Modulated Lock-In Vibrothermography for NDE of Polymers and Composites

1995 ◽  
Vol 7 (1) ◽  
pp. 215-228 ◽  
Author(s):  
J. Rantala ◽  
D. Wu ◽  
G. Busse
Keyword(s):  
Lock In

A Raman signature of the incommensurate-commensurate phase transition (lock-in) in a crystalline monomer diacetylene : pTS

1982 ◽  
Vol 43 (5) ◽  
pp. 755-759 ◽  
Author(s):  
M. Bertault ◽  
M. Krauzman ◽  
M. Le Postollec ◽  
R.M. Pick ◽  
M. Schott
Keyword(s):  
Phase Transition ◽  
Commensurate Phase ◽  
Lock In

Examination of Measurement Method for Magnetostriction of Electrical Steel Sheet with Lock-in Amplifier

2012 ◽  
Vol 132 (11) ◽  
pp. 1033-1038
Author(s):  
Yuichiro Kai ◽  
Yuji Tsuchida ◽  
Takashi Todaka ◽  
Masato Enokizono
Keyword(s):  
Measurement Method ◽  
Steel Sheet ◽  
Electrical Steel ◽  
Lock In ◽  
Electrical Steel Sheet

Frequency sweep implementation of adaptive multi-level substructuring

1997 ◽  
Author(s):  
Jeffrey Bennighof ◽  
Matthew Kaplan ◽  
Jeffrey Bennighof ◽  
Matthew Kaplan
Keyword(s):  
Frequency Sweep ◽  
Multi Level
Sign in / Sign up

Export Citation Format

Share Document