Term
Which of these four values for pulse repetition frequency would have the longest pulse repetition period
A. 2kHz
B. 4,000 Hz
C. 6 Hz
D. 1 kHz |
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Definition
| C. 6 Hz Pulse repetition period is the reciprocal of pulse repetition frequency. This choice has the lowest pulse repetition frequency and, thus, the longest pulse repetition period. |
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Term
Four pulses have pulse repetitition periods 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 |
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Definition
| C. 5 ms. The pulse with the shortest pulse duration will have the highest pulse repetition frequency. |
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Term
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. 400 ks |
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Definition
| C. 20 kHz Pulse repetition period is the reciprocal of pulse repetition frequency. This answer has the highest pulse repetition frequency and, thus, the shortest pulse repetition period. |
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Term
Four waves have pulse repetition periods as listed below. Which of the following four waves has the lowest pulse repetition frequency.
A. 8 s
B. 80 us
C. 8000 ns
D. 800 ms |
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Definition
| A. 8 s. The pulse with the longest pulse duration will have the lowest pulse repetition frequency. |
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Term
| True or False. Two waves can have identical pulse repetition frequencies, even if their pulse repetition periods are different. |
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Definition
| False. Two waves can never have identical PRFs if their pulse repetition periods are different. |
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Term
| True of False. Two waves can have identical PRFs, even if their periods are different. |
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Definition
| True. Period and pulse repetition frequency are unrelated. |
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Term
| True or False. Two waves can have identical PRFs, even if their frequencies are different. |
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Definition
| True. Frequency and pulse repetition frequency are unrelated. |
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Term
| True or False. PRF and pulse repetition period are determined only by the imaging depth. |
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Definition
| True. This is a very important concept. |
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Term
| If all other factors remain unchanged, what happens to the duty factor [increases, decreases, remains the same] when the pulse repetition frequency increases? |
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Definition
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Term
| If all other factors remain unchanged, what happens to the duty factor [increases, decreases, remains the same] when imaging depth increases? |
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Definition
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Term
| If all other factors remain unchanged, what happens to the duty factor [increases, decreases, remains the same] when pulse repetition period increases? |
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Definition
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Term
| If all other factors remain unchanged, what happens to the duty factor [increases, decreases, remains the same] when the sonographer uses a new transducer with a longer pulse duration? |
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Definition
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Term
What is the duty factor if the pulse duration is 1 us and the pulse repetition period is 1 ms
A. 100 %
B. 0.1
C. 0.01
D. 0.001 |
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Definition
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Term
Which of the following terms does not belong with the others?
A. high duty factor
B. shallow imaging
C. low PRF
D. short pulse repetition period |
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Definition
| C. Low PRF is associated with deep imaging. The other three choices are all associated with shallow imaging. |
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Term
Which of the following terms does not belong with the others?
A. low duty factor
B. shallow imaging
C. low PRF
D. long pulse repetition period |
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Definition
| B. Shallow imaging does not belong. The other three choices are all associated with deep imaging. |
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Term
| _______ is the time from the start of a pulse to the end of that pulse. |
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Definition
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Term
| _______ is the time from the start of a pulse to the start of the next pulse. |
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Definition
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Term
By changing the imaging depth, which of the folowing does the operator also change (more than 1 may be correct)?
A. pulse repetion frequency
B. duty factor
C. propagation speed
D. pulse repetition period
E. amplitude
F. spatial pulse length |
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Definition
A, pulse repetition frequency.
B, duty factor.
D, pulse repetition period. |
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Term
| The speed of 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 propagation speed. |
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Definition
| The propagation speed for the pulsed and continuous wave sound is the same; in this case, 1.8 km/s. It depends only upon the medium through which the sound travels |
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Term
| What is the duty factor if the pulse duration is 1 microsecond, and the pulse repetition period is 1 ms? |
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Definition
| The duty factor is 0.001, or 10 neg 3. 10 neg 6 divided by 10 neg 3 = 10 neg 3, or 0.001. |
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Term
| What is the duty factor if the pulse duration is 1 millisecond, and the pulse repetition period is 1 second? |
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Definition
| The duty factor is 0.001 or 0.1% 0.001 divided by 1.0 = 0.001. |
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Term
A sonographer adjusts the depth of view of an ultrasound scan form 8 cm to 16 cm. Would each of the following parameters increase, decrease, or remain the same?
A period
B. frequency
C. wavelength
D. speed
E. amplitude (initial)
F. pulse duration
G PRF
H. duty factor
I. spatial pulse length
J. pulse repetition period |
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Definition
A. remains the same
B. remains the same
C. remains the same
D. remains the same
E remains the same
F. remains the same
G decreases
H. decreases
I. remains the same
J. increases |
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Term
A sonographer is using a 3 MHz transducer and changes to a 6 MHz transducer. The imaging depth remains unchanged. Would each of the following parameters increase, decrease, or remain the same?
A. period
B. frequency
C. wavelength
D. speed
E. intensity (initial)
F. PRF
G. pulse repetition period |
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Definition
A.decreases
B increases
C decreases
D remains the same
F. remains the same
G. remains the same |
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Term
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 each of the following parameters increase, decrease, or remain the same?
A. period
B frequency
C. wavelength
D. speed
E. power (initial)
F intensity (initial)
G. pulse duration
H. PRF
I. duty factor
J. spatial pulse length
K. pulse repetition period |
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Definition
A. remains the same
B. remains the same
C. remains the same
D. remains the same
E. increases
F increases
G. remains the same
H. remains the same
I remains the same
J. remains the same
K. remains the same |
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