Ultrasonic sensor detecting Doppler shift caused by target movements - has compensation system which suppresses artifacts caused by sensor movements

摘要

The ultrasonic transducer (1) directs pulsed signals at a target, e.g. large blood vessels inside the human body, and detects echoes. The echo signal is processed (25) by a demodulator (21) and frequency calculator (22), before being fed to an image processor (23) and visual display unit (24). The compensation circuit in the signal processor compares each echo signal, W2, with an average, W1, of previous signals. The output of the compensation circuit is an average of the two signals, i.e. (W2 + W1)/2.