P1g: Wireless Signals

Today’s hi-tech world demands that people can always receive both phone calls and email very rapidly. This item develops ideas about global communication, the benefits of wireless transmission, and the impact of this culture on modern society. The expanding use of digital signals is examined. 

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How are wireless signals reflected? What does this mean?
Wireless signals can be reflected off buildings and other large objects. This means that signals may be received even if the receiver is not in direct sight of the transmitter.
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What type of radiation can be used for wireless signals? Give two examples.
Electromagnetic. E.g. radio waves are used to transmit television and radio programmes and microwaves are used to transmit mobile phone calls.
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What are the four advantages of wireless technology?
Allows access when on the move, no external/direct connection to a telephone wire needed, portable and convenient.
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What is the disadvantage of wireless technology?
An aerial is needed to pick up the signals.
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What can happen to radiation used for communication?(2)
It can be refracted/reflected.
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What can refraction and reflection be for a good signal?(2)
A disadvantage or an advantage.
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Give a disadvantage of reflection.
It can cause ‘ghosting’ on television pictures.
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Give four common uses of wireless technology.
Mobile phones, Radio, Laptops and TV.
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What do long distance communications depend on?
The refraction and resulting reflection of waves from the ionosphere being received by and re-transmitted from satelittles.
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Talk about the refraction of radio waves.
Radio waves are refracted by different layers in the Earth’s atmosphere. This leads to a reduction in the signal, making it difficult for them to be received over long distances.
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Talk about the refraction of microwaves.
microwaves are not refracted, so they are used for satellite communications.
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What is the refraction and refection in the ionosphere similar to?
TIR for light.
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Why do nearby radio stations use different transmission frequencies?
Radio stations whose transmitters are near each other need to broadcast on different frequencies to avoid interference between the signals.
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Give two advantages of DAB broadcasts.
DAB makes more radio stations available and suffers from less interference from other broadcasts.
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Give two disadvantages of DAB broadcasts.
DAB may have a poorer audio quality than FM, and not all areas of the UK are currently covered by DAB broadcasts.
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How can refraction of radiation affect communications?
At the interfaces of different layers at the Earth's atmosphere.
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How can diffraction of radiation affect communications?
By transmission dishes resulting in signal loss.
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Explain the main advantage of using DAB.
They suffer less interference so many signals can broadcast at the same frequency - multiplexing - so an increase in the potential number of radio stations available.
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Other cards in this set

Card 2

Front

What type of radiation can be used for wireless signals? Give two examples.

Back

Electromagnetic. E.g. radio waves are used to transmit television and radio programmes and microwaves are used to transmit mobile phone calls.

Card 3

Front

What are the four advantages of wireless technology?

Back

Preview of the front of card 3

Card 4

Front

What is the disadvantage of wireless technology?

Back

Preview of the front of card 4

Card 5

Front

What can happen to radiation used for communication?(2)

Back

Preview of the front of card 5
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