Abstract: A transmitter circuit assembly in an ultrasonic diagnostic system intermittently transmitting ultrasonic energy in bursts beamed through a probe into an organism according to control parameters defined by organic diagnostic requirements input into the circuit assembly. The transmitter circuit assembly includes a probe drive-signal output circuit driving the probe-to emit ultrasonic energy; a drive voltage determining circuit determining drive signal voltage, and a circuit computing a drive voltage-limit reference voltage, both voltages being determined according to the control parameters defined by the organic diagnostic requirements; and a drive signal transmission prohibition circuit comparing the drive voltage with the reference voltage and prohibiting the drive signal from being output when the drive voltage is higher than the reference voltage.