Physics-Describing Pulsed Waves

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 Author: aprilh4485 ID: 115203 Filename: Physics-Describing Pulsed Waves Updated: 2011-11-07 15:34:35 Tags: Sonography Folders: Description: Describing Pulsed Waves Show Answers:

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1. Which of these four values for pulse repetition frequency would have the longest pulse repetition period?
A. 2 kHz
B. 4000 Hz
C. 6 Hz
D. 1 kHz
• C. 6 Hz
• PRP and PRF are recipricals. This choice has the lowest pulse repetition frequency and, thus, the longest pulse repetition period.
2. Four pulses have PRPs as listed below. Which of the following four waves has the highest pulse repetition frequency?
A. 8 s
B. 80 ms
C. 5 ms
D. 400 ks
• C. 5 ms
• The pulse with the shortest pulse duration will have the highest pulse repetition frequency.
3. Which of these four pulses with PRFs listed below has the shortest pulse repetition period?
A. 12 kHz
B. 6,000 Hz
C. 20 kHz
D. 1 kHz
• C. 20 kHz
• The highest PRF will have the shortest PRP.
4. Four waves have PRPs as listed below. Which of the following four waves has the lowest PRF?
A. 8 s
B. 80 μs
C. 8000 ns
D. 800 ms
• A. 8 s
• The pulse with the longest pulse duration will have the lowest PRF
5. True or False.
Two waves can have identical pulse repetition frequencies, even if their pulse repetition periods are different.
• False.
• Two waves never have idendical PRFs if their PRPs are different
6. True or False.
Two waves can have identical PRFs, even if their periods are different.
• True.
• Period and PRF are unrelated.
7. True or False.
Two waves canhave identical PRFs, even if their frequencies are different.
• True.
• Frequency and PRF are unrelated.
8. True or False.
PRF and PRP are determined only by imaging depth.
• True.
• This is a very important concept!!
9. If all other factors remain unchanged, what happens to the duty factor (increases, decreases, or remains the same) when the PRF increases?
increases
10. If all other factors remain unchanged, what happens to the duty factor (increases, decreases, remains the same) when imaging depth increases?
decreases
11. If all other factors remain unchanged, what happens to the duty factor (increases, decreases, or remains the same) when the PRP increases?
decreases
12. If all other factors remain unchanged, what happens to the duty factor (increases, decreases, or remains the same) when the sonographer uses a new transducer with a longer pulse duration?
increases
13. What is the duty factor if the pulse duration is 1 μs and the PRP is 1 ms?
A. 0.01
B. 100%
C. 0.1
D. 0.001
D.
(this multiple choice question has been scrambled)
14. Which of the following terms does not belong with the others?
A. shallow imaging
B. short PRP
C. high duty factor
D. low PRF
D. low PRF is associated with deeper imaging. The other choices are associated with shallow imaging
(this multiple choice question has been scrambled)
15. Which of the following terms does not belong with the others?
A. low PRF
B. low duty factor
C. shallow imaing
D. long PRP
C. shallow imaging does not belong. The other choices are associated with deeper imaging
(this multiple choice question has been scrambled)
16. __________ is the time from the start of a pulse to the end of that pulse.
Pulse duration
17. __________ is the time from the start of one pulse to the start of the next pulse.
pulse repetition period (PRP)

18. What are the duty factors of the 4 waves that appear in the figure?
• wave A: 100%
• wave B: 33%
• wave C: 0%
• wave D: 50%
• Hint: to determine a duty factor, use a single pair of complete pulse duration and PRP times.

19. Which of the patterns in the figure indicates a system with superficial imaging depth?
D. it has the shallowest imaging depth because PRP is shortest

20. Which of the patterns in the figure indicates a system with a deep imaging depth?
B. it has the deepest imaging depth because the PRP is the longest.

21. Which two of the patterns in the figure identify an ultrasound system that cannot perform anatomic imaging?
• A. it is continuous wave and does not create images
• C. cannot perform imaging because it does not produce sound.

22. What best describes A?
pulse duration
23. What best describes B?
amplitude

24. What best describes C?
pulse repetition period (PRP)

25. What best describes D?
period and wavelength

26. What best describes E?
listening time only

27. What best describes F?
peak to peak amplitude

28. What best describes the duty factor?
• A/C
• Duty factor is calculated by dividing the pulse duration by the PRP
29. Pulse repetition frequency is the reciprocal of _________.
PRP
30. By changing the imaging depth, which of the following does the operator also change? (more than one may be correct)
A. PRF
B. duty factor
C. propagation speed
D. PRP
E. amplitude
F. spatial pulse length
PRF, duty factor, PRP
31. The speed fo a 5 MHz continuous wave is 1.8 km/sec. The wave is then pulsed with a duty factor of 0.5. Calculate the new speed.
the propagation speed for pulsed and continuous wave sound is the same, 1.9 km/s. It depends only upon the medium through which it is traveling.
32. What is the duty factor if the pulse duration id 1 microsecond, and the PRP is 1 ms?
• 0.001 or 10-3
• 10-6 divided by 10-3 = 10-3
33. What is the duty factor if the pulse duration is 1 millisecond, and PRP is 1 second?
• 0.001 or 0.1%
• 0.001 divided by 1.0 = 0.001
34. A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would PERIOD increase, decrease, or remain the same?
remains same
35. A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would FREQUENCY increase, decrease, or remain the same?
remains same
36. A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would WAVELENGTH increase, decrease, or remain the same?
remains same
37. A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would SPEED increase, decrease, or remain the same?
remains same
38. A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would AMPLITUDE (INITIAL) increase, decrease, or remain the same?
remains same
39. A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would PULSE DURATION increase, decrease, or remain the same?
remains same
40. A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would PULSE REPETITION FREQUENCY increase, decrease, or remain the same?
decreases
41. A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would DUTY FACTOR increase, decrease, or remain the same?
decreases
42. A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would SPATIAL PULSE LENGTH increase, decrease, or remain the same?
remains same
43. A sonographer adjusts the depth of view of an ultrasound scan from 8 cm to 16 cm. Would PULSE REPETITION PERIOD increase, decrease, or remain the same?
increases
44. A sonographer is using a 3 MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would PERIOD increase, decrease, or remain the same?
decreases
45. A sonographer is using a 3 MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would FREQUENCY increase, decrease, or remain the same?
increases
46. A sonographer is using a 3 MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would WAVELENGTH increase, decrease, or remain the same?
decreases
47. A sonographer is using a 3 MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would SPEED increase, decrease, or remain the same?
remains same
48. A sonographer is using a 3 MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would INTENSITY (INITIAL) increase, decrease, or remain the same?
remains same
49. A sonographer is using a 3 MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would PULSE REPETITION FREQUENCY increase, decrease, or remain the same?
remains same
50. A sonographer is using a 3 MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would PULSE REPETITION PERIOD increase, decrease, or remain the same?
remains same
51. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would PERIOD increase, decrease, or remain the same?
remains same
52. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would FREQUENCY increase, decrease, or remain the same?
remains same
53. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would WAVELENGTH increase, decrease, or remain the same?
remains same
54. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would SPEED increase, decrease, or remain the same?
remains same
55. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would POWER (INITIAL) increase, decrease, or remain the same?
increases
56. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would INTENSITY (INITIAL) increase, decrease, or remain the same?
increases
57. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would PULSE DURATION increase, decrease, or remain the same?
remains same
58. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would PULSE REPETITION FREQUENCY increase, decrease, or remain the same?
remains same
59. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would DUTY FACTOR increase, decrease, or remain the same?
remains same
60. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would SPATIAL PULSE LENGTH increase, decrease, or remain the same?
remains same
61. A sonographer is using a 3 MHz transducer and increases the output power to visualize structures that are positioned deeper in the patient. No other controls are adjusted. Would PULSE REPETITION PERIOD increase, decrease, or remain the same?
remains same

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