What does the autogain button mean on an ultrasound machine

Autogain. ultrasound was invented in 1950 by Professor Ian Donald of the University of Glasgow, Scotland, UK, and was first used in gynecological examinations. And autogain button on b ultrasound machine is the meaning of auto gain, turn on this will keep the total output volume constant when adjusting the parameters.B ultrasound machine utilizes the physical properties of ultrasound for diagnosis and treatment of an imaging discipline called ultrasound medicine.