Wave Theory

Question 1

Speed of light in nm

Answer 1

162 000 nm/s

Question 2

Amplitude

Answer 2

Distance between the top of the wave and zero value

Question 3

Anti phase

Answer 3

Opposite and cancel each other out

Question 4

Doppler effect

Answer 4

Frequency can be effected by the relative movement of the waves from the origination source

Question 5

Frequency shift

Answer 5

Occurs when a transmitter and a receiver move in relation to each other

Question 6

Modulation

Answer 6

Altering the wave to carry information

Question 7

4 types of modulation

Answer 7

Pulse
Frequency
Phase
Amplitude

Question 8

Imposing

Answer 8

To include speech or data information, a wave needs to be imposed on a carrier wave

This process of imposing is called modulation

Question 9

Amplitude modulation

Answer 9

Positive signal = high amplitude
Negative signal = low amplitude

Gets interference from the environment

Question 10

Frequency modulation

Answer 10

Putting a long frequency on a high frequency wave
High amplitude = high frequency on the carrier wave
Low amplitude = low frequency on the carrier wave

Question 11

Phase modulation

Answer 11

Complex modulation technique that requires a complex demodulator

Only current practical use is the GPS

Carrier wave is reversed

Question 12

Pulse modulation

Answer 12

Turning the signal on and off

Question 13

Side bands

Answer 13

Side product of imposing waves, radiation

Single side band (SSB) is used in VHF coms - VOLMET and normal coms

Question 14

Classification of radio signals 1st character

Answer 14

Type of modulation of the main carrier

Question 15

Classification of radio signals 2 nd character

Answer 15

Nature of the signal

Question 16

Classification of radio signals 3rd character

Answer 16

Type of info transmitted.