The physical medium over which the information is transmitted.
Oops!
Check
Okay!
Check
10
What are sky waves?
Radio waves reflected from the ionosphere by total internal reflection.
Oops!
Check
Okay!
Check
10
What is the effect of frequency modulation (FM) on the amplitude of the carrier wave?
None, the amplitude is constant but the frequency is varied depending on frequency variations of the audio signal.
Oops!
Check
Okay!
Check
10
What process do high-frequency carrier radio waves undergo before transmission over long distances?
Modulation using audio signal information.
Oops!
Check
Okay!
Check
5
Do FM or AM signals have higher noise immunity?
FM.
Oops!
Check
Okay!
Check
15
What is the relationship between AM bandwidth and the highest frequency in the audio signal, fH?
In amplitude modulation (AM), the carrier waveform amplitude is altered depending on variations in the audio signal: AM bandwidth = 2fH
Oops!
Check
Okay!
Check
25
What are 3 advantages of optical fibres compared to coaxial cables?
1. Larger bandwidth. 2. Lower attenuation of signal. 3. More secure.
Oops!
Check
Okay!
Check
20
What are Coaxial cables?(constructure, uses)
2 wire conductors, a signal transmits through a conductor which is surrounded by an insulator, an earthed wire braid protects from any interference.
Oops!
Check
Okay!
Check
20
What are some advantages of digital to analogue?
The signal is able to be regenerated so there is minimal noise. Extra data can be added so the signal can be checked for errors.
Oops!
Check
Okay!
Check
boom
Lose 50 points!
Oops!
gift
Win 10 points!
Okay!
rocket
Go to first place!
Okay!
lifesaver
Give 15 points!
Oops!
banana
Go to last place!
Oops!
gift
Win 20 points!
Okay!
shark
Other team loses 25 points!
Okay!
banana
Go to last place!
Oops!
20
What are microwave links?
Line of sight transmission paths to receive and transmit information at microwave frequencies.
Oops!
Check
Okay!
Check
20
What are 4 reasons for modulation?
1. Less interference. 2. A shorter aerial can be used. 3. Less attenuation. 4. Less distortion.
Oops!
Check
Okay!
Check
15
What are wire pairs? One example of uses
Wire pairs are links between information transmitters and receivers. Nowadays they are used for low frequency short distance communications, e.g. doorbells.
Oops!
Check
Okay!
Check
15
Which is a digital signal?
A digital signal is a signal which consists of a series of highs and lows with no intermediate values.