Chapter 16/17 Q&A: quiz 1

Question 1

An uncompressed signal within the receiver of an ultrasound system has a dynamic range of 110dB. The signal undergoes 40dB of compression. What is the dynamic range of the compressed signal?

Answer 1

The dynamic range of the compressed signal is:

110dB - 40dB = 70dB

Question 2

An uncompressed signal has a dynamic range of 85dB. The signal undergoes 30dB of compression. What is the dynamic range of the compressed signal?

Answer 2

85dB - 30dB = 55dB

Question 3

After compression, a signal within the ultrasound system has a dynamic range of 70dB. The original signal was compressed by 40dB. What is the dynamic range of the original, uncompressed signal?

Answer 3

The dynamic range of the original signal is 70dB + 40dB = 110dB

Question 4

A signal within a system’s receiver has a dynamic range of 60dB after compression. The original signal was compressed by 50dB. What is the dynamic range of the original, uncompressed signal?

Answer 4

60dB + 50dB = 110dB

Question 5

Sound with a frequency of 4MHz is created by a transducer. What is the fundamental frequency?

Answer 5

4 MHz

Question 6

Sound with a frequency of 4MHz is created by a transducer. What is the harmonic frequency?

Answer 6

8MHz

Question 7

What creates harmonics?

Answer 7

nonlinear behavior

Question 8

Where are harmonics created?

Answer 8

in the tissues

Question 9

What nonlinear behavior creates tissue harmonics?

Answer 9

Tissue harmonics are created by nonlinear behavior; sound travels faster in compressions and slower in rarefactions.

Question 10

What nonlinear behavior creates contrast harmonics?

Answer 10

Contrast harmonics are created by nonlinear behavior; microbubbles expand to a greater extent than they compress.

Question 11

What is associated with the highest mechanical index?

Answer 11

low frequency, extreme peak rarefactional pressure