Fourier transform of high frequency ultrasonic waves propagated with a transmission mode
Abstract
When ultrasonic propagates as a wave, the frequencies contained in the propagated waves may carry information regarding to the medium. The transformation of time-domain propagated signals into those of frequency domain is a common digital signal processing (DSP) technic to extract such important information. This requires quite a high resolution of the detection device which relates to the high frequency ultrasonic waves. The advancement of microprocessor technologies enables the complex and fast digital signal processing in the frequency domain. This allows measurement and evaluation using a broadband frequency domain analysis which is effective in the extraction of information contained in the ultrasonic signals. This work presents the implementation of Fourier transform of propagated ultrasonic signals through air medium. The generation of ultrasonic waves employs two pairs of transmitter-receiver ultrasonic transducers which have the center frequencies of 200 kHz and 1 MHz, respectively. The transmitter transducer was excited by a 107.1-ns negative spike to generate ultrasonic waves propagating through the air and converted into an electrical signal by a receiver transducer. This was amplified and recorded as a digital signal for subsequent offline digital signal processing.
- Publication:
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Journal of Physics Conference Series
- Pub Date:
- August 2018
- DOI:
- 10.1088/1742-6596/1080/1/012034
- Bibcode:
- 2018JPhCS1080a2034H