| 摘要 |
<p>ULTRASONIC TRANSMITTER/RECEIVER An ultrasonic transmitter/receiver for moving member measurement wherein an ultrasonic pulse beam is transmitted into and received from a subject under examination at a fixed pulse-repetition frequency, the signal received during each transmission/reception cycle is compared with the signal received during the previous transmission/reception cycle to obtain a Comparison signal and the movement of a moving member in the subject is detected and measured on the basis of the comparison signal. The ultrasonic transmitter/receiver is further provided with a scanner for causing an ultrasonic beam to reciprocally scan the subject, a memory for storing comparison signals at addresses corresponding to the scanning positions of the ultrasonic beam, the memory being responsive to address data representing the scanning position of the ultrasonic beam to output the comparison signal stored at the corresponding address one scan earlier and simultaneously store at the same address the comparison signal for the same scanning position of the current scan, and an adder for adding the comparison signal for said position of the current scan and the comparison signal for said position one scan earlier output by the memory, whereby scanning noise contained in the comparison signals is eliminated.</p> |
