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Questions and Answers
What is pulse duration?
What is pulse duration?
The actual time from the start of a pulse to the end of that pulse
What is the pulse duration equation?
What is the pulse duration equation?
Pulse duration (μs) = # of cycles in pulse x period (μs)
Shorter duration pulses are desirable for imaging because they create images of greater accuracy.
Shorter duration pulses are desirable for imaging because they create images of greater accuracy.
True
What is spatial pulse length (SPL)?
What is spatial pulse length (SPL)?
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What is the relationship of spatial pulse length to cycles and wavelength?
What is the relationship of spatial pulse length to cycles and wavelength?
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What is pulse duration?
What is pulse duration?
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What is the distance of the pulse end to end referred to?
What is the distance of the pulse end to end referred to?
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What is the equation for spatial pulse length?
What is the equation for spatial pulse length?
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What characteristics contribute to long pulses?
What characteristics contribute to long pulses?
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What characteristics lead to short pulse lengths?
What characteristics lead to short pulse lengths?
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What is pulse repetition period?
What is pulse repetition period?
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When imaging at shallow depths, the time from one pulse to the next is long.
When imaging at shallow depths, the time from one pulse to the next is long.
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When imaging more deeply, the time from one pulse to the next is longer.
When imaging more deeply, the time from one pulse to the next is longer.
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Pulse repetition period is unrelated to the period.
Pulse repetition period is unrelated to the period.
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Pulse repetition period and imaging depth are directly related.
Pulse repetition period and imaging depth are directly related.
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What can a sonographer not change regarding pulse duration?
What can a sonographer not change regarding pulse duration?
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Only the listening time portion of the pulse repetition period is changed when the sonographer alters imaging depth.
Only the listening time portion of the pulse repetition period is changed when the sonographer alters imaging depth.
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What is pulse repetition frequency (PRF)?
What is pulse repetition frequency (PRF)?
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How are pulse repetition frequency and depth related?
How are pulse repetition frequency and depth related?
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What is the relationship between pulse repetition period and pulse repetition frequency?
What is the relationship between pulse repetition period and pulse repetition frequency?
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What is the equation for pulse repetition frequency?
What is the equation for pulse repetition frequency?
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Which of these four values of pulse repetition frequency would have the longest pulse repetition period?
Which of these four values of pulse repetition frequency would have the longest pulse repetition period?
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Which of the following four waves has the highest pulse repetition frequency?
Which of the following four waves has the highest pulse repetition frequency?
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Which of these four pulses with PRS listed below has the shortest pulse repetition period?
Which of these four pulses with PRS listed below has the shortest pulse repetition period?
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Which of the following four waves has the lowest pulse repetition frequency?
Which of the following four waves has the lowest pulse repetition frequency?
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Two waves can have identical pulse repetition frequencies even if their pulse repetition periods are different.
Two waves can have identical pulse repetition frequencies even if their pulse repetition periods are different.
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Two waves can have identical PRFs even if their periods are different.
Two waves can have identical PRFs even if their periods are different.
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Two waves can have identical PRFs even if their frequencies are different.
Two waves can have identical PRFs even if their frequencies are different.
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What is duty factor?
What is duty factor?
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Study Notes
Pulse Duration
- Defines the time from the start to the end of a pulse, measured in time units.
- Is determined by the sound source and is not adjustable.
Pulse Duration Equation
- Calculated as: pulse duration (μs) = number of cycles in pulse x period (μs).
Imaging and Pulse Duration
- Shorter duration pulses enhance imaging accuracy.
Spatial Pulse Length (SPL)
- Represents the distance occupied by a pulse, measured in distance.
- Determined by both the sound source and the medium, and is non-adjustable.
- Directly proportional to the number of cycles and wavelength, and inversely proportional to frequency.
SPL Equation
- Calculated as: SPL (mm) = number of cycles x wavelength (mm).
- Characteristics for long pulses include many cycles and longer wavelengths, while short pulse lengths have fewer and shorter wavelength cycles.
Pulse Repetition Period
- The interval from the start of one pulse to the next, measured in time.
- Determined by the sound source and is adjustable.
Imaging Depth and Pulse Repetition Period
- Imaging at shallow depths results in shorter intervals between pulses.
- Deeper imaging causes longer intervals.
- PRP and imaging depth have a direct relationship.
Pulse Duration and Sonographer Control
- Sonographers cannot change pulse duration as it is a fixed characteristic of the transducer.
Altering Imaging Depth
- Only the listening time portion of the pulse repetition period is modified when imaging depth is adjusted.
Pulse Repetition Frequency (PRF)
- Indicates the number of pulses transmitted per second, measured in Hz.
- Determined by the sound source, which is not adjustable.
PRF and Depth Relationship
- Inversely related: increasing depth decreases PRF, while decreasing depth increases PRF.
Pulse Repetition Period and Frequency Relation
- They are reciprocals: a longer PRP corresponds to a lower PRF and a shorter PRP corresponds to a higher PRF.
PRF Equation
- Expressed as: PRF x PRP = 1, or PRF = 1/PRP.
Multiple Choice Questions on PRF
- The longest pulse repetition period is associated with a PRF of 6 Hz.
- A pulse repetition period of 5 ms corresponds to the highest PRF.
- A PRF of 20 kHz corresponds to the shortest pulse repetition period.
- The pulse repetition frequency with the lowest value is associated with a period of 8 s.
True or False Statements
- Two waves cannot have identical PRFs if their pulse repetition periods differ (False).
- Identical PRFs may exist even if their periods are different (True).
- Two waves can have identical PRFs even if their frequencies differ (True).
Duty Factor
- Represents the proportion of time that the system is actively transmitting pulses.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your understanding of key concepts from Chapter 4 on ultrasound physics with these flashcards. Focus on important terms like pulse duration and its impact on imaging accuracy. Perfect for reinforcing knowledge for exams or class discussions.
