Ultrasound imaging systems are based on the principle of pulse echo imaging. These systems require the use of short pulses of ultrasound to create two-dimensional, sectional images. Basically, a transducer pulses energy into a patient for a very short period of time and follows this pulse with a long silent period allowing the transducer to "listen" for returning echoes without interference from other outgoing pulses. The pulse of electricity that excites the transducer ranges from 1-300 volts and lasts less than 1 microsecond (µs).
Pulsed ultrasound MUST be used to create an image. Continuous wave ...