Lesson 3 (Part 1)

Question 1

What does the T/R switch involve? (2)

Answer 1

1. Transmission channel

2. Reception channel

Question 2

What does the T/R switch do? (2)

Answer 2

1. Directs the returning echo voltage from the transducer to the amplifiers during reception
2. Protects the sensitive inputs from the larger voltages

Question 3

What does T/R prevent?

Answer 3

Incorrect direction of a signal

- acts as a traffic cop

Question 4

Which is stronger, the beam going out or coming back?

Answer 4

The beam going out

Question 5

What do amplifiers normally receive?

Answer 5

A weaker signal

- attenuated

Question 6

What happens if the amplifier receives a stronger voltage from the pulser/pulse delay?

Answer 6

The amplifier gets overloaded

Question 7

What does the T/R switch protect?

Answer 7

The amplifiers from the outgoing voltage

Question 8

What happens to the voltage at the transducer?

Answer 8

The pulse is converted to an electrical signal

Question 9

What gets sent to the amplifier?

Answer 9

The electrical signal that was converted from the pulse

Question 10

What does an amplifier do?

Answer 10

It increases voltage amplitude

Question 11

Amplification

Answer 11

Is the conversion of the smaller voltages received from the transducer elements to larger ones for storage

Question 12

Gain

Answer 12

Is the ratio of the output of the amplifier to the electric power input

Question 13

How is power ratio expressed?

Answer 13

In decibles

- dB

Question 14

What is the formula for gain?

Answer 14

Gain = output power/inputpower

Question 15

What is another term for gain?

Answer 15

Power ratio

Question 16

What is power ratio equal to?

Answer 16

Power ratio = voltage ratio^2

Question 17

What is amplification the opposite of?

Answer 17

Attenuation

• attenuation = -10
• amplification = +10

Question 18

What is 3dB equal to in intensity?

Answer 18

2x

Question 19

What is 10dB equal to in intensity?

Answer 19

10x

Question 20

What is used to counteract attenuation?

Answer 20

Amplifiers

Question 21

What are amplifiers involved with?

Answer 21

Gain/TGC

Question 22

What does gain control determine?

Answer 22

How much amplification is accomplished by the amplifier

Question 23

What happens if you have too little gain?

Answer 23

Weak echos are not expressed

Question 24

What happens if you have too much gain?

Answer 24

Saturation occurs

- cant get proper readings

Question 25

Why is the gain set?

Answer 25

So that echos appear with an appropriate brightness

Question 26

What does each channel have?

Answer 26

An amp that amplifies the voltages

Question 27

What can you figure out once you have voltage?

Answer 27

Power

- power ratio = voltage ratio^2

Question 28

What do amplifiers allow for? (2)

Answer 28

1. Amplification

2. Compensation

Question 29

TGC

Answer 29

Time gain compensation

Question 30

Time gain compensation

Answer 30

Equalizes the differences in the received echo amplitude arriving at the transducer if their travel distances are different

Question 31

What is another word for time gain compensation?

Answer 31

Depth gain compensation

Question 32

What happens to sound as you travel?

Answer 32

It gets weaker

Question 33

What does TGC produce?

Answer 33

Uniform brightness throughout the image

Question 34

How is TGC set?

Answer 34

By the operator

Question 35

Compensation

Answer 35

Amplification at specific depths