Which of the following statements accurately describes demodulation?

1. Which Doppler controls need adjustment in this spectral display?

 

a. scale; gain; angle correction

b. baseline shift; invert; wall filter

c. invert; baseline; angle correction

d. sample gate size, baseline shift; wall filter

2. Which of the following is equal to one half of the pulse repetition frequency?

a. Nyquist limit

b. pulsatility index

c. Reynolds number

d. attenuation coefficient

3. Equal intensity for all similar structures regardless of the depth is a function of:

a. suppression

b. rectification

c. amplification

d. compensation

4. Which imaging technique is most likely to visualize structures beneath a highly attenuating structure?

a. pulse inversion

b. pixel interpolation

c. spatial compounding

d. harmonic frequencies

5. Contrast agents improve visualization by increasing:

a. scatter

b. reflection

c. refraction

d. reverberation

6. Frequency is proportional to:

a. period

b. attenuation

c. wavelength

d. penetration depth

7. Which of the following changes will optimize the diagnosis of this sonogram?

a. increase overall gain c. controls the amplitude of the received signals

d. adjusts the pulse repetition frequency for imaging depth

4. The knee of a time gain compensation curve represents the:

a. area of minimum amplification

b. area of maximum amplification

c. depth at which variable compensation begins

d. deepest region attenuation compensation can occur

5. Which component of the ultrasound system adjusts the pulse repetition frequency with changes in imaging depth?

a. pulser

b. T/R switch

c. beam former

d. master synchronizer

6. The transmit and receiver switch is part of which of the following instruments?

a. pulser

b. receiver

c. beam former

d. digital scan converter

7. Which of the following constitutes a transmission channel?

a. an electrical voltage and an element

b. an electrical voltage and firing delay

c. a delay path and an individual element

d. an independent pulse delay and an element

8. Which of the following statements accurately describes demodulation?

a. Demodulation suppresses low-level echoes.

b. Demodulation changes the gray-scale charac­teristics of an image.

c. Structure boundaries are accentuated when using demodulation.

d. Processing the received signal is made possible by demodulation.

9 Which of the following receiver functions decreases acoustic noise?

a. smoothing

b. threshold

c. rectification

d. compression

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