Method and device for detecting and determining irregularities in the flow of a medium

摘要

In order to detect and determine irregularities in the flow of a medium, such as a blood circulation, signal waves of acoustic signals which emanate from the flowing medium are monitored by means of the Doppler effect, the amplitude of the received Doppler signal being determined continuously and the fluctuations thereof being measured continuously, it being the case, moreover, that the frequency of the received Doppler signal is continuously determined from the temporal spacing of its zero crossings and fluctuations of this frequency are measured in this process, it being the case, furthermore, that higher frequencies are raised and the raised frequencies thus generated are continuously determined from the temporal spacing of the zero crossings of the same and fluctuations of these frequencies are measured, the two frequencies thus determined being compared to one another and the comparison signals being obtained in the process being visualised by means of the signals corresponding to the amplitude for the purpose of evaluation. The comparison of the frequencies can be performed by subtracting or dividing.