MECHANICAL SECTOR TYPE ULTRASONIC DIAGNOSTIC APPARATUS

摘要

PURPOSE:To eliminate the error caused by the measurement of a dimension on an image by minimizing the shaking or strain of the image and to reduce an erroneous diagnosis by calculating the error of a scanning position generated corresponding to negative load on the basis of the data of a rotary position and controlling a motor driving circuit so as to correct said error. CONSTITUTION:At first, a change-over switch 23 is operated to apply DC voltage to the motor in an ultrasonic probe. An angle-of-rotation detector 25 always monitors the signal of a rotary encoder 14 and calculates the speed variation corresponding to a rotary position on the basis of the data of the rotary position and the load data from a load torque calculator 28. A PLL control circuit 24 compares the phase of a corrected reference timing clock with that of the signal from the rotary encoder 14 to perform the PLL control of a motor driving circuit 21 and realizes constant speed rotation wherein the speed variation due to the load variation during rotation is corrected. By this method, the scanning speed of the ultrasonic probe is made constant and the strain or shaking of an image can be eliminated.