Spi Prep Questions |296 Questions| With Correct Answers.

383. US systems using these transd do not actually steer the US beams to create a 2D image. a. linar switched (or linear sequential) array transd b. linear phased array transd c. mechanical transd d. annular phased array transd e. convex or curvilinear array transd f. vector array transd {Ans: a and e Linear and convex switched (or sequential arrays) do not steer sound beams. Rather, a small group of elements produce a pulse that travels straight ahead.}338. What will lower the value of an US system's lateral res? a. decrease the # of cycles in the pulse b. increase the effective damping material c. increase the pulse repetition period d. use an acoustic lens {Ans: d. use an acoustic lens To lower the numerical value of lateral res of an US syst, the diameter of the beam must be reduced. A commonly used technique to decrease the diameter of the beam is to focus the beam with an acoustic lens}Which of the following statements about doppler is most correct? a. non directional doppler uses phase quadrature processing, while bi directional doppler uses coherent processing b. non directional doppler uses autocorrelation processing, while bi directional doppler uses phase