Arrays and transducer mechanics Flashcards
What is an annular array?
A transducer built with concentric circular elements.
Why is an annular array built with concentric circular elements?
They are built with circular elements to provide multiple focal zones. Focus is electronic but beam steering is mechanical.
What is the difference between a sequential linear array and a phased array?
A sequential linear array fires groups of elements and has a rectilinear display. A phased array has a smaller footprint and creates a sector shaped display.
At what gain setting does ultrasound become harmful to human tissue?
It’s a trick question. Gain is amplification of the return echo, it has nothing to do with what goes into tissue. That would be transmit power.
How is a beam formed?
The pulser creates pulses of voltage that travel to the transducer and produce sound. The pulser also determines PRF/PRP by controlling the timing of electrical pulses.
What does the beam former do?
The beam former contains the circuitry that times the electrical pulses that shape and steer the beam.
What is Apodization?
Apodization is a process within the beam former that reduces grating lobes ( extra sound energy at the sides of the beam that can degrade the image.
