Week 15 Pulsed Echo Instrumentation Part 2

Question 1

What are the order of Receiver Operations?

Answer 1

1. Amplification
2. Compensation
3. Compression
4. Demodulation
5. Reject

Question 2

Is amplification adjustable?

Answer 2

Yes

Question 3

How are the signals processed with Amplification?

Answer 3

All signals are treated identically.

Question 4

What effect does amplification have on an image?

Answer 4

Entire image gets brighter or darker

Question 5

Is Compensation adjustable?

Answer 5

Yes

Question 6

How are the signals processed with Compensation?

Answer 6

Signals treated differently based on reflector depth.

Question 7

What effect does compensation have on an image?

Answer 7

Image will be uniformly bright from top to bottom.

Question 8

Is Compression adjustable?

Answer 8

Yes

Question 9

How are the signals processed with Compression?

Answer 9

Signals are treated differently depending on the strength.

Question 10

What effect doe compression have on an image?

Answer 10

Changes gray scale mapping

Question 11

Is Demodulation adjustable?

Answer 11

No

Question 12

How are the signals processed with demodulation?

Answer 12

Prepares electrical signals to be suitable for display.

Question 13

What are the effects of demodulation on an image?

Answer 13

NONE

Question 14

Is reject or suppression
or threshold adjustable?

Answer 14

Yes

Question 15

How are the signals processed with reject?

Answer 15

Only weak signals are affected: Strong signals remain unchanged.

Question 16

What are the effect of reject on an image?

Answer 16

Weak echoes appear or are eliminated from an image.

Question 17

What are the units of Amplification?

Answer 17

Db

Question 18

What is the typical value of amplification?

Answer 18

60-100 Db

Question 19

Output power:

Answer 19

1. Changes brightness of the entire image
2. alters signal-to-noise ratio
3. alters patient exposure
4. bioeffect concerns
5. Decreases this first if image is too bright

Question 20

Receiver Gain:

Answer 20

1. Changes brightness of entire image.
2. Does not affect signal-to-noise ratio
3. Does not change patient exposure
4. No bioeffect concerns
5. Increase this first if image is too dark.

Question 21

What are the 2 ways Demodulation forms more suitable displays on a monitor?

Answer 21

1. Rectification
2. Smoothing

Question 22

What is Rectification?

Answer 22

Converts all negative voltages into positive voltages.

Question 23

What is smoothing or enveloping?

Answer 23

Places a smooth line around the “bumps” and evens them out.

Question 24

What is the purpose of preamplification?

Answer 24

process of improving the signal quality before amplification.

Question 25

Which receiver function will provide this image with equal brightness?

Answer 25

compensation

Question 26

“Compensation” receiver function is needed to ______.

Answer 26

correct for attenuation

Question 27

Another name for TGC’s are ______.

Answer 27

swept gain
compensation
depth gain compensation

Question 28

What could happen if the gain is not optimized appropriately throughout the image?

Answer 28

deeper structures may not be seen

Question 29

Which receiver function is important for seeing differences in weak reflections.

Answer 29

compression

Question 30

Due to ALARA which would you use first to decrease the energy emitted?

Answer 30

output power