CIRCUIT FOR GENERATING ULTRASONIC TRANSMISSION PULSE FOR ULTRASONIC TOMOGRAPHY DEVICE

摘要

PURPOSE:To always transmit the input signal as continuous wave transmission at the TTL level with simple and inexpensive construction by connecting diodes in the reverse direction for the polarity of the power supply across the resistances to be connected between the gate and source of one FET. CONSTITUTION:A ultrasonic transmission pulse generation circuit in the ultrasonic diagnostic device used for blood flow measurement is provided with a pair of FETs 11 and 12 of N and P channel type with the drain D connected each other. The source S of one FET 11 is grounded and the source S of the other FET 12 is connected to the power supply +HV. A capacitor C1 is connected between the both gates G. Resistance R1 is connected between the gate B and the source S of the FET 12, and a signal Vin from an FET driver 15 consisting of a reference signal generating circuit 14 and a TTL circuit is inputted to an input terminal IN. The diode D1 is connected across the resistance R1 so as to output a continuous wave signal by means of the input vibration at the TTL level.