Abstract
Microprocessor-based correlation processing is now widely used for the estimation of foetal heart rate from ultrasonic Doppler signals. The paper describes a technique having a, similar performance, to correlation but which will run three times faster on a microprocessor without an onboard hardware multiplier. This speed improvement results from replacing each multiplication operation of the correlation algorithm with a subtraction and a modulus operation. The algorithm, is thus referred to as the modulus difference algorithm. Typical waveforms are presented illustrating the responses of the two processors to continuous wave Doppler foetal heart signals for both wide (50 Hz) and narrow (4 Hz) preprocessor bandwidths. A quantitative comparison is given of the performance of the two methods in estimating the period of a synthetic signal with additive white Gaussian noise. This simulation represents the wideband preprocessor case. A theoretical derivation of the outputs for the narrowband preprocessor case is given, and actual outputs are shown for comparison. A tutorial approach is adopted throughout the paper.
Similar content being viewed by others
References
Atkinson, P. andWoodcock, J. P. (1982)Doppler ultrasound and its use in clinical measurement. Academic Press.
Bendat, J. S. andPiersol, A. G. (1980)Engineering applications of correlation and spectral analysis. Wiley.
Cousin, A. J. (1980) On processing of Doppler returns from the foetal heart: acoustic requirements for extraction of valvular timing information.Med. & Biol. Eng. & Comput.,18, 563–568.
Flynn, A. M. andKelly, J. (1977) Evaluation of fetal well-being by antepartum fetal monitoring.Br. Med. J.,1, 936.
Moorer, J. A. (1974) The optimum comb method of pitch period analysis of continuous digitized speech.IEEE Trans.,ASSP-22, 330–338.
Neilson, J. M. (1974) High speed anlaysis of ventricular arrhythmias from 24 hour recordings. InComputers in Cardiology. IEEE Computer Society, 55–61.
Patrick, J. E., Dalton, K. J. andDawes, G. S. (1976) Breathing patterns before death in fetal lambs.Am. J. Obstet. Gynecol.,125, 73.
Pearson, J. F. andWeaver, J. B. (1976) Fetal activity and fetal well-being: an evaluation.Br. Med. J.,1, 1305.
Ross, M. J., Schafer, H. L., Cohen, A., Freudberg, R. andManley, H. J. (1974) Average magnitude difference function pitch extractor.IEEE Trans.,ASSP-22, 221–226.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Manning, G.K., Dripps, J.H. Comparison of correlation and modulus difference processing algorithms for the determination of foetal heart rate from ultrasonic Doppler signals. Med. Biol. Eng. Comput. 24, 121–129 (1986). https://doi.org/10.1007/BF02443924
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02443924