G9 Wave Model - Going Digital

Gapfill exercise

Enter your answers in the gaps. When you have entered all the answers, click on the "Check" button.

   analogue      binary      booster      computers      decoded      diode-laser      electrical      information      interference      loss      more      multipath      multiplexing      optical      photo-diode      pulses      sampled      tapped      thinner   
Telecommunications are ways of transmitting information over long distances.

Analogue and Digital Systems
Continuous variations in the voltage of a signal are called signals.
These signals can be converted to digital signals. The original signal is many times a second. The measurements are converted into (1 and 0) and transmitted as a series of . At the receiving end they are and turned back into signals.
Digital transmission has many advantages.
1. Digital signals can be handled by
2. Digital signals can carry more every second than analogue ones.
3. Digital signals can be delivered without a of quality.

Transmitting through optical fibres
For long-distance transmission, fibres are used. These carry the signals as pulses of light produced by light-emitting diodes (LEDs) or a . At the receiving end a picks up the light signals and converts them into signals.
Optical fibres are and lighter than electrical cables, and carry many more signals. Electrical signals need stations because the signal gets weak quite quickly. With optical fibres the booster stations can be much further apart.
Optical signals are not affected by electrical and cannot be into by other people.

Digital Radio
DAB (Digital Audio Broadcasting) can use many stations than the AM and FM systems, and produces higher-quality broadcasts. In the AM and FM systems, reflection from hills and buildings give . Digital systems use the signals to improve the quality.
DAB transmitters all use the same frequency using a method called which allows many signals to be sent alongside each other.