Title :
High frequency broadband arbitrary coded excitation in ultrasound microscopy
Author :
Merilainen, A.I. ; Fabritius, Tapio ; Eskelinen, J. ; Haeggstrom, Edward
Author_Institution :
Dept. of Phys., Univ. of Helsinki, Helsinki, Finland
Abstract :
We built a 200+ MHz ultrasound microscope that can employ broad band arbitrary coded signals. Our solution is based on quadrature modulation and T/R-switching. We show that the instrument works with linear and non-linear chirp signals (100 - 300 MHz). We imaged a 5 μm tall MEMS step structure with our device and with a commercial pulser, the results were comparable. Cross-talk from the local oscillator in the quadrature modulator affects the pulse compression. This limits the use of codes at the oscillator frequency.
Keywords :
acoustic microscopes; acoustic microscopy; acoustic signal processing; chirp modulation; crosstalk; micromechanical devices; ultrasonic materials testing; MEMS step structure; T/R-switching; broadband arbitrary coded signals; commercial pulser; cross-talk; frequency 100 MHz to 300 MHz; high frequency broadband arbitrary coded excitation; local oscillator; nondestructive imaging; nonlinear chirp signal; oscillator frequency; pulse compression; quadrature modulation; quadrature modulator; science imaging; surface profiling; ultrasound microscope; ultrasound microscopy; Chirp; Frequency modulation; Local oscillators; Micromechanical devices; Microscopy; Ultrasonic imaging;
Conference_Titel :
Ultrasonics Symposium (IUS), 2012 IEEE International
Conference_Location :
Dresden
Print_ISBN :
978-1-4673-4561-3
DOI :
10.1109/ULTSYM.2012.0614
