A new modulation method with range resolution for ultrasonic Doppler flow sensing

Abstract This paper proposes a new pair of sequences whose cross-correlation values are zero except for the peak value and presents a new modulation method for an ultrasonic Doppler flowmeter with high sensitivity utilizing these sequences. In this method, transmitted and received waves are modulated and demodulated, respectively, by the specified new sequences. Since unfavourable reflected waves can be almost completely eliminated by this proposed modulation method, a high signal-to-noise ratio is easily achieved. Elementary experimental results are also given.