Describing Pulsed Waves Practice Flashcards

The actual time from the start of a pulse to the end of that pulse; uses μs; determined by sound source; not adjustable

Pulse Duration

A sequence of short bursts of energy separated by periods of no transmission, rather than a continuous flow

Pulsed Waves

The distance that a pulse occupies in space from the start to the end of a pulse; units of distance; determined by source and medium; not adjustable

Spatial Pulse Length

Which kind of waves create anatomic images?

Pulsed waves

Made up of many cycles or longer periods

Long Pulse

Preferred in ultrasound; made up of fewer cycles or shorter periods

Short Pulse

The number of pulses that an ultrasound system transmits into the body each second; units of hertz; determined by sound source; is adjustable

Pulse Repetition Fequency

Higher frequency, shorter wavelength, and fewer cycles per pulse all shorten the SPL, and create what kind of images?

High quality images

The time from the start of one pulse to the start of the next pulse: units of μs and ms; determined by the sound source and imaging depth

Pulse Repetition Period

If you change the depth of your image, you are also changing what?

Pulse Repetition Period

Depth and PRP are related how?

Directly

Difference between pulse duration and SPL?

Pulse duration measures time and SPL measures length

SPL is directly proportional to what?

Number of cycles in the pulse and wavelength

Shorter Imaging

Shorter listening time

Deep Imaging

Longer listening time

How are pulse repetition frequency and depth of view related?

Inversely related

When the system is imaging shallow, the PRF is what?

Higher

When the system is imaging deep, the PRF is what?

Lower

PRP and PRF have what kind of relationship?

Inverse

Which of these values for PRF has the longest PRP?

6Hz

Which of the following PRFs listed will have the shortest PRP?

20kHz

Two waves can have identical PRF, even if their PRP are different?

False

Pulse repetition period are determined only by the imaging depth

True

The percentage or fraction of time that the system transmits a pulse; no units; determined by sound source; is adjustable

Duty Factor

How is duty factor calculated?

pulse duration / PRP x 100

Maximum value of duty factor?

1 or 100%

Minimum value of duty factor?

0%

Which of the following terms does not belong with the others?

Low PRF

What is the duty factor if the pulse duration is 1μs and the PRP is 1 ms?

0.001

What is being demonstrated in this image?

Pulse Repetition Period (PRP)

What is being demonstrated in this image?

Pulse Repetition Frequency (PRF)

What is being demonstrated in this image?

Pulse Duration

What is being demonstrated by the red and blue arrows in the image?

Red arrow: Long Pulse

Blue Arrow: Short Pulse

Which is the continuous wave and which is the pulsed wave?

Top: Continuous

Bottom: Pulsed