| 摘要 |
PURPOSE:To automatically set an STC curve with good reproducibility, by mounting an STC (Sensitivity Time Control) curve control signal generating circuit comparing the value of a comparing value calculation circuit with the reference value from a reference value generating circuit and increasing and decreasing a gain corresponding to the magnitude of both values. CONSTITUTION:A comparing value calculation circuit 20 calculates an average value at every depth regions l1-l5 and a control circuit 28 reads each of the reference values calculated at every depth regions l1-l5 from a reference value generating circuit 22 on the basis of the code number of an examinee and applies the same to the comparator 30 of an STC curve control signal generating circuit 24 along with the average value to compare both values. An STC curve forming circuit 8 responds to the depth change-over signal applied from the control circuit 28 in matching relation to the receiving timing of the ultrasonic echo corresponding to the intermediate point of the depth regions l1-l5 and the output of a counter 42 is changed over by a multiplexer MPX. Said output is applied to a D/A converter 44 as an STC control signal through the multiplexer MPX to be converted to an analogue value and the integrated value thereof is applied to a main amplifier 6 from an integration circuit 46. By this method, an STC curve can be automatically reset to as to coincide with the reference value.
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