circuit by using the voltage controlled oscillator vco or the apparatus having the similar functions in the practical the low pass filter for the filter 44 will be selected as fig5 the second embodiment showing the second preferred embodiment for the signal processing circuit there are the clock controller 51 the microprocessor 52 and the filter 53 the microprocessor 52 can produce the square wave signal by using the coding method then the filter 53 will adjust the square wave signal to become as the output wave v 1 of the sinusoidal wave in the practical the low pass filter for the filter 53 will be selected observing the result of the test experimentation for the invention especially the effect of the multiple frequency ultrasound system using unique transducer ultrasonic and judging the strength of the u201c acoustic cavitation effect u201d will be carried out by using the binarization method in order to calculate the amount of the air bubble as fig6 a under the condition for the different output power for example 1 watt 2 watts 3 watts 4 watts 5 watts comparing with the produced air bubble amount by the single frequency for example f 83 khz ultrasound actuating about 5 air bubbles will be obtained under 4 watts another about 10 air bubbles will be obtained in 5 watts as fig6 b under the condition for the different output power for example 1 watt 2 watts 3 watts 4 watts 5 watts comparing with the produced.