1. Means communication at distance
Tele-communication
Means communication at distance

2. Not a New Idea

3. Early developments for passing messages

4. The modern era Telegraph started in Europe in 1830s
Electronic transmission of morse code
Under the Atlantic in Cables
Radio transmissions from early 20th Century
Usually one way though there were radio phones
Use radiowaves
Telephone patented 1876 Alexander Graham Bell (but others involved!)
Converts sound into electronic messages in mouth piece
Message converted back to sound at other end. Used electric cables

5. The phone

6. Changes to the phone Changed to optical fibre Became mobile
Used satellites for long-distance
Now use microwave signals boosted by phone masts

7. Basic physics Energy Understanding technology
Use longer parts of EM Spectrum
Understanding
Basic grasp of wave behaviour
technology
Optical fibres
Microwave transmissions
Digital signals

8. Transverse: em spectrum
Waves
Longitudinal: sound
Transverse: em spectrum

9. Key terms 1.
When waves interact you get constructive or destructive interference 2.
Waves bouncing off things is called reflection 3.
Waves passing through materials change speed and therefore direction at boundaries. This is called refraction.

10. Wave interference

11. Reflection

12. Refraction

13. Total internal reflection

14. Optical fibre

15. Why replace copper 1. 2. 3. Fibre bundles much finer Much lighter
Carry much more information. Separate messages can pass down same cable simultaneously.

16. Signals

17. Satellite transmission

18. Attenuation
Over a distance the energy in a signal is dissipated as it spreads out so the signal at any one point gets weaker.
This is why we need phone, tv and radio masts to boost the signals.
Imagine as you move away from a light source in the night – its effect gets less. It is just the same with radiowaves and microwaves.

19. Electromagnetic spectrum

20. EM spectrum telecommunication1.
light –
optical fibres 2. IR
remote controls 3
microwaves
Telephones, GPS 4
UHF TV 5
Radio waves
Radio transmissions

21. A bit of physics V = λ x f Where v = velocity λ = wavelength
f = frequency
In the case of em spectrum v is called c as in Einstein´s famous equation
E = mc²
C = 3 x 108 m/s
Rearrange the equation to find the frequency of 15 cm microwaves.

22. 1. 2. 3. This means As wavelength gets longer frequency gets lower
High frequency waves attenuate more quickly so need regular boosting 2.
This is why we need lots of phone masts
But relatively few radio masts. 3.

23. Types of signal

24. Practical difference
Analogue
Digital

25. Benefits and disadvantages of analogue
Allows much greater info. storage
Easier to reproduce
Easier to send and transport
Looses information

26. Does it matter? Then Our brain perceives the
Information to be analogue
Why not?
Our senses sample information
Like a digital signal
Digital loses information
But does it matter?
No!

27. e.g. film A moving picture is made up of 24 still frames a second
Our eyes use this discrete information and our brain perceives it as if we were looking at movement in normal life.
Conversely digital allows us now to project many more frames per second giving much greater resolution e.g phantom cameras.

28. Challenge: A poster Financial and business benefits
Timeline of the development of telecommunications
Social benefits
Financial and business benefits
Must include benefits to poor people
Environmental costs
Social costs
Must include an academic article on effects on society or individual
Explain a key area of telecommunicational technology

29. Rubric Marks Timeline Social benefits Social costs Economic benefit
Environmentalcosts
Example of technology
Effort 1
A comment 2
A relevant statement or comment 3
Some elements of task acheived 4
Generally achieved with some omissions or faults. 5
Includes all elements with times to scale
Explains how it has changed our lives for the better with before and after examples supported by quotes
Explanation of harm to society clearly put and based on a referenced article
Clearly explains how people benefit comapred with before and must include example alleviating poverty
Identifies pollution issues at all stages of life cycle with examples of types of harm
One area of technology explained in detail with diagrams
Full effort recorded by teacher and confirmed by team leader.