Filtering of chirped ultrasound echo signals with the fractional Fourier transform

Michael J. Bennett, Steve McLaughlin, Tom Anderson, N McDicken

Research output: Chapter in Book/Report/Conference proceedingConference contribution

20 Citations (Scopus)


The fractional Fourier transform represents a generalisation of the conventional Fourier transform. Previous work [2] has shown that the application of the fractional Fourier transform to conventional, un-coded ultrasound signals has little advantage over conventional filtering techniques such as bandpass filtering. However, the fractional Fourier transform can he 'tuned' to be sensitive to signals of a particular chirp rate [4] and can achieve levels of pulse compression similar to those obtained using a matched filter. To this end a system was developed which could generate and transmit linear chirp coded ultrasound signals. The fractional Fourier transform was then used to process the signals received from a simple phantom arrangement. When the transform was used with the 'optimum' transform order corresponding to the chirp rate of the signals, the transform domain signals demonstrated a degree of pulse compression similar to that given by a matched filter. Results are also presented which demonstrate that a chirp signal identified in the fractional Fourier domain may be completely recovered in the time domain through the use of the inverse transform. Matched filtering was found to give a greater degree of pulse compression, but the fraction Fourier method can be applied without a-priori knowledge of the transmitted signal. Further work will be carried out to determine the best way of extracting useful information from the fractional domain signals.

Original languageEnglish
Title of host publication2004 IEEE Ultrasonics Symposium, Vols 1-3
EditorsMarjorie Passini Yuhas
Number of pages5
ISBN (Print)0-7803-8413-X
Publication statusPublished - 2004
Event2004 IEEE Ultrasonics Symposium - Montreal, Canada
Duration: 23 Aug 200427 Aug 2004


Conference2004 IEEE Ultrasonics Symposium


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