Abstract
Three methods of deriving directional signals from phase quadrature Doppler signals, using digital techniques, are described. These are the phasing-filter technique, the Weaver receiver technique and the complex FFT. The basic theory behind the three methods is presented, together with the results of digital simulations. Each of the methods has been implemented in real time using a commercially available digital signal-processing board, and their relative processing times are compared. All the methods work well, and the decision to implement one or other in a specific application is likely to rest on secondary factors, such as the need to tape-record the time domain output.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Abu-El-Haije, A. I., andAl-Ibrahim, M. M. (1986): ‘Improving performance of digital sinusoidal oscillators by means of error feedback circuits’,IEEE Trans.,CAS-33, pp. 373–380
Ansari, R. (1987): ‘IIR discrete-time Hilbert transformers’,IEEE Trans.,ASSP-35, pp. 116–119
Brigham, E. O. (1974): ‘The fast Fourier transform’ (Prentice-Hall, Inc., Englewood Cliffs, New Jersey) pp. 11–49
Bush, G., andEvans, D. H. (1993): ‘Digital audio tape as a method of storing Doppler ultrasound signals’,Physiol. Meas. 14, pp. 381–386
Coghlan, B. A., andTaylor, M. G. (1976): ‘Directional Doppler techniques for detection of blood velocities’,Ultrasound Med. Biol.,2, pp. 181–188
Fliege, N. J., andWintermantel, J. (1992): ‘Complex digital oscillators and FSK modulators’,IEEE Trans.,SP-40, pp. 333–342
Furuno, K., Mitra, S. K., Hirano, K., andIto, Y. (1975): ‘Design of digital sinusoidal oscillators with absolute periodicity’,IEEE Trans.,AES-11, pp. 1286–1299
Gold, B., Oppenheim, A. V., andRader, C. M. (1970): ‘Theory and implementation of discrete Hilbert transform’.Proc. Symp. Comput. Process. Comm. (Polytechnic Press), pp. 235–250
Oppenheim, A. V., andSchafer, R. W. (1975): ‘Digital signal processing’ (Prentice-Hall, Inc., Englewood Cliffs, New Jersey) pp. 337–366
Rabiner, L. R., andSchafer, R. W. (1974): ‘On the behaviour of minimax FIR digital Hilbert transformers’,Bell Syst. Tech. J.,53, pp. 363–389
Schwartz, M., Bennett, W. R., andStein, S. (1966): ‘Communication systems and techniques’ (McGraw-Hill, Inc.) pp. 29–35
Smallwood, R. H. (1985): ‘Recording Doppler blood flow signals on magnetic tape’,Clin. Phys. Physiol. Meas.,6, pp. 357–359
Taylor, F. J. (1983). ‘Digital filter design handbook’ (Marcel Dekker, Inc., New York and Basel), pp. 183–188
Weaver, D. K. Jr. (1956): ‘A third method of generation and detection of single-sideband signals’,Proc. IRE,44, pp. 1703–1705
AT&T Microelectronics (1990): WE DSP32C Digital Signal Processor Information Manual
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Aydin, N., Evans, D.H. Implementation of directional Doppler techniques using a digital signal processor. Med. Biol. Eng. Comput. 32 (Suppl 1), S157–S164 (1994). https://doi.org/10.1007/BF02523342
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02523342