Comparisons between PW Doppler system and enhanced FM Doppler system

Jens E. Wilhjelm, P. C. Pedersen

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This paper presents a new implementation of an echo-ranging FM Doppler system with improved performance, relative to the FM Doppler system reported previously. The use of long sweeps provides a significant reduction in peak to average power ratio compared to pulsed wave (PW) emission. A PW Doppler system exploits the direct relationship between arrival time of the received signal and range from the transducer. In the FM Doppler systems, a similar relationship exists in the spectral domain of the demodulated received signals, so that range is represented by frequency. Thus, a shift in location of moving scatterers between consecutive emissions corresponds to a frequency shift in the spectral signature. The improvement relative to the earlier version of the FM Doppler system is attained by utilizing cross-correlation of real spectra rather than of magnitude spectra for assessing flow velocity. This approach requires a priori knowledge of the envelope of the received sweep from a point scatterer
Original languageEnglish
Title of host publicationProceedings of the IEEE Ultrasonics Symposium
VolumeVolume 2
Publication date1995
ISBN (Print)07-80-32940-6
Publication statusPublished - 1995
Event1995 IEEE Ultrasonics Symposium - Seattle, WA, United States
Duration: 7 Nov 199510 Nov 1995


Conference1995 IEEE Ultrasonics Symposium
Country/TerritoryUnited States
CitySeattle, WA

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