Digital Signal Processing Implementation of a Novel Ultrasonic Doppler Flowmeter

摘要

Advanced high-speed digital signal processing (DSP) techniques were developed to improve performances of conventional ultrasonic Doppler flowmeters (UDFs). First the reflected ultrasonic Doppler signal was AGC (Automatic Gain Compensation) amplified, then digitized by a high-speed analog-to-digital (A/D) converter (12-bits, 40-MSPS), demodulated and filtered by a TMS320VC5410 DSP device based on a digital mixer and an 8-order low-pass (LP) digital Butterworth filter. Finally, the DSP device was applied to analyze spectrum of the demodulated Doppler shift signal based on a modified covariance (MCOV) estimator and work out the flow velocity. A simulation analysis was also presented to demonstrate effectiveness of this DSP implementation. Then, a few comparisons between the novel and the conventional UDFs were discussed in detail. Results indicate that the novel UDFs are more effective than the conventional UDFs in terms of accurate and stable flow measurement.