Authors: Karel Hajek; Josef Sikula
Addresses: Department of Electrical Engineering, University of Defence, Kounicova 65, 66210, Brno, Czech Republic. ' Department of Physics, FEKT, BUT Brno, Technicka 8, 616 00 Brno, Czech Republic
Abstract: This paper presents comparison of two basic methods of ultrasonic non-linear modulation spectroscopy and proposes new possibilities for rising of sensitivity. The rising of sensitivity by lowering of a dynamic range of the measured signals by using of analogue linear pre-filtration for suppressing of excitation signals is discussed in the first part. The second part discusses the possibility of using the burst exciting mode for ultrasonic non-linear modulation methods. The excitation by phase coupled burst signals is derived for obtaining of the resultant long time signal without the waste of its useful energy. The new variant of mixing method with burst signals is derived, where the linear analogue pre-filtration is used for the attenuation of exciting signals in sensing signal for the rising of signal processing dynamic range and the increasing of practical sensitivity.
Keywords: NDT; nondestructive testing; nonlinear spectroscopy; ultrasound; cracks; burst exciting; localisation; analogue prefiltration; digital signal processing; DSP; nonlinear modulation.
International Journal of Microstructure and Materials Properties, 2011 Vol.6 No.3/4, pp.283 - 292
Available online: 20 Oct 2011 *Full-text access for editors Access for subscribers Purchase this article Comment on this article