Medical Ultrasound Source Output Sound Intensity Testing Instrument

Accompany with the continuous development of the medical treatment and family planning, ultrasonic diagnosis already becomes one of the essential medical treatment instruments with the clinic. In the past ten years, people use ultrasonic to diagnose a patient, detect and show the acoustics characteristic of human body's organization and organ to examine the disease. At the same time of people use various ultrasonic detectors in clinic, the safety problem of ultrasonic detectors becomes very important but doesn't thoroughly resolve yet. Since 1980's, this problem is more arrestive. One of its backgrounds is ultrasonic diagnosis expands increasingly in the application of the obstetrics and gynecology, cause the possible influence problem of early pregnancy diagnosis becomes very sensitive; the second is the ultrasonic exportation of some Doppler imaging apparatuses tend to high, is existence of the latent insecurity arouse people's concern. Therefore, the National Quality and Technology Supervision Administration draw up and promulgate national standards and measurement calibration regulations to restrict and normalize the exportation of the medical ultrasonic source.This text commences from the basic contents of ultrasonic, introduces the basic concept of ultrasonic realm, and emphasis on introducing the definition of acoustic intensity and acoustic power. Because measurand is average acoustic intensity of time and space, according to the relationship of acoustic intensity and acoustic power, the system turns to measure acoustic power. There are many methods for measuring acoustic power, and the system adopts the classic radiometric force method, this kindof method also matches to original purpose-portable type, good stability, andeasy to spot measurement. The system improves the radiometric force method on the textbook, it places the vertical circular target instead of vertical taper target or horizontal circular target, and the type of target is total reflection. The system also spread sound absorbing material inside the water tank all over; make sure the almost total function of ultrasonic. The system adopts the magnetoelectricity type force balance service-detecting method. Its principle is that the current in the electric coil of the balance system interact with stationary magnetic field of moving coil, then a driving moment produced balances with the moment of radiation pressure in ultrasonic beam's functioning on the total reflection target, as a result, the system can get the relationship of electric current and acoustic power, mechanical parameters' measurement turns to electricity parameters' measurement, and the system can adopt some common circuits to carrying out the measurement of electricity parameters. The whole thinking way is a conversion method of Acoustic to Force to Electricity, and then carry out the high accuracy for measurement.In the following data-processing, the system adopts MC14433 type A/D conversion chip for realizing a display, then the system sends the BCD type data code to a computer by RS232 interface, the examination software judges qualified or not automatically, and it can make a qualified certificate or examination result notification finally.