Block 3 Concepts

Question 1

What type of signal has a modulation index of 1

Answer 1

100% modulated

Question 2

An over-modulated AM signal is more efficient than a 100% modulated signal.

Answer 2

True

Question 3

Envelope detector

Answer 3

a mechanism to demodulate an AM signal

Question 4

What does an envelope detector use?

Answer 4

diode, LPF, and HPF

Question 5

Which signals can an envelope detector be used?

Answer 5

100% modulated and under-modulated

Question 6

LOS is the only wireless channel that works for every frequency range. T/F

Answer 6

True

Question 7

In frequency modulation:
A. The frequency of the carrier changes
B. The frequency of the message changes
C. The amplitude of the carrier changes
D. The amplitude of the message changes

Answer 7

A. The frequency of the carrier changes

Question 8

What are the four types of communication channels?

Answer 8

Transmission lines
Fiber optics
Waveguides
Wireless

Question 9

Examples of transmission lines

Answer 9

Ethernet cable, coaxial cable

Question 10

Examples of fiber optics

Answer 10

fiber optic lines

Question 11

Examples of waveguides

Answer 11

antenna feeds

Question 12

Examples of wireless

Answer 12

radio

Question 13

. What are the three types of basic antennas

Answer 13

Dipole: Length = λ/2, Gain = 1.64
Monopole: Length = λ/2, 3.28
Dish antenna: Length = r, Gain = p2πrq2λ2 η