The development of an ultrasound flow velocity signal processing unit and studies in the flow velocity measurements using time and phase domain techniques

Clinical ultrasonic systems provide only video output signals which limit the data acquisition and signal processing capability from current systems. The purpose of this study is to develop a pulsed Doppler ultrasound signal processing unit. The architecture of this system include: central frequency generator, PRF generator, echo signal demodulator, and sample volume setting circuit. The computation architecture included FFT Doppler spectrum, autocorrelation phase shift and cross-correlation time shift analysis. The acquired RF and baseband signals were used for calculations of FFT, autocorrelation, and cross-correlation to verify the flow velocity measurements.