1. Analogue and Digital

2. Digital and Analogue 1.What change is happening between 2008 and 2012? 2.List some of the ways that digital TV can be sent. 3.List two advantages of digital television compared to analogue television. 4.How are analogue signal sent? 5.How are digital signals sent?

3. Analogue Radio

6. Analogue Signals

7. Digital Radio

8. The sound is ‘sampled’ The values are send using binary numbers Lets learn to count in binary

9. Counting in Binary There are 10 types of people in this world, those that understand binary and those who don’t.

10. Digital Signals

11. Are these digital or analogue? 1.A light switched on or off. 2.A CD (information stored as hole or no hole) 3.A light with a dimmer switch. 4.A continuous variable. 5.A discrete variable. 6.An AM radio signal. 7.A DAB radio signal.

12. Digital Music The binary data you are about to see is the result from breaking down 1 millisecond of CD quality music (The Beatles — Let It Be). 5 seconds worth at the same font size would have taken over 1000 pages, so try to imagine how much data is stored on a CD containing 20 tracks, each 4 minutes long!!!

14. Advantages of Digital Signals Digital signals are less prone to interference than analogue.

15. Why don’t digital signals suffer from interference?

16. Adding Noise

17. Advantages of Digital Signals Digital signals can be easily be processed by computers. –Text (SMS) messages –Picture (Bitmap) editing –Sound (Wave -.wav) editing Digital signals are less prone to interference than analogue.

18. Bitmaps Jpegs, Gifs and Tiffs are bitmaps. These are essential ‘paint by numbers’ The picture is made up of picture elements –Shortened to Pixels Each pixels has a number associated with it which refers to a colour

19. Advantages of Digital Signals Digital signals can send information faster –More information in the same amount of time –Interactive TV Digital signals are less prone to interference than analogue. Digital signals can be easily be processed by computers.

20. Tele-Text

21. Multiplexing We can send digital information quicker than its needed for real time communications This allows us to use the same wire to send more than one phone call, for example

22. What are the advantages of Digital Signals Digital signals are less prone to interference than analogue. Digital signals can be easily be processed by computers. Digital signals can send information faster