Beath High School - Int 1 Physics1 Intermediate 1 Physics Telecommunication Radio Television Satellites Optical Fibres Telephone

Beath High School - Int 1 Physics2 Intermediate 1 Physics Telecommunication Radio

Beath High School - Int 1 Physics3 At one time a radio was called a "wireless" because the signal it received did not come through w _ _ _ _. A radio transmitter s _ _ _ _ out invisible waves of energy which can be picked up by an aerial r _ _ _ _ _ _ _. wires. sends receiver. Radio

Beath High School - Int 1 Physics4 The radio waves can travel through air the air at a speed of metres per s _ _ _ _ _. ( = 300 hundred million.) This means that they travel l _ _ _ _ distances in a very short time. second. large Radio

Beath High School - Int 1 Physics5 Parts of a radio receiver A radio is an electronic system which is used to detect radio w _ _ _ _ and change them into speech and music. Every radio has five main parts, all having a different j _ _ to do. waves job Radio

Beath High School - Int 1 Physics6 The five parts are, a _ _ _ _ _ t _ _ _ _ d _ _ _ _ _ _ a _ _ _ _ _ _ _ _ l _ _ _ _ _ _ _ _ _ Parts of a radio receiver aerial tuner decoder amplifier loudspeaker Radio

Beath High School - Int 1 Physics7 Aerial- Detects all r _ _ _ _ waves. Tuner- Selects one radio s _ _ _ _ _ _ by picking out one frequency. Decoder- Separates the s _ _ _ _ signal from the radio w _ _ _. Amplifier- Makes the small electrical s _ _ _ _ _ stronger. (The extra e _ _ _ _ _ is supplied to the amplifier by a battery or the mains). Loudspeaker- Changes the e _ _ _ _ _ _ _ _ _ signal into a sound wave. Functions of the main parts of a radio radio station sound wave. signal energy electrical

Beath High School - Int 1 Physics8 Each radio station broadcasts on a d _ _ _ _ _ _ _ _ radio frequency. The f _ _ _ _ _ _ _ _ of a wave is the number of waves produced in one second. The frequency is measured in h _ _ _ _ (Hz). Radio frequency different Hz = 1 _ _ _ _ hertz (kHz) This means waves in one second Hz = 1 _ _ _ _ hertz (MHz) This means waves in one second. frequency hertz kilo mega

Beath High School - Int 1 Physics9 A h _ _ _ frequency wave looks like this: Radio frequency high A l _ _ frequency wave looks like this: low

Beath High School - Int 1 Physics10 You can t _ _ _ a radio by selecting the frequency you want. Radio frequency tune Forth 1 has a frequency of _ _. _ MHz ( Hz) and is a local FM radio station. 97.3

Beath High School - Int 1 Physics11 The medium wave band (MW) contains l _ _ _ _ frequency radio stations like Radio 5, which has a frequency of 909 kHz ( _ _ _ _ _ _ Hz). Radio frequency lower Signs at the side of motorways give d _ _ _ _ _ _ information about radio frequencies. drivers FM stations have a h _ _ _ _ _ frequency than medium wave (MW) higher

Beath High School - Int 1 Physics12 Intermediate 1 Physics Telecommunication Television

Beath High School - Int 1 Physics13 A television receiver picks up very h _ _ _ frequency radio waves. These signals travel at 300 million m _ _ _ _ _ per second through the air but have a higher frequency than signals from a r _ _ _ _ transmitter. This means radio and T.V. signals travel at the s _ _ _ speed Television radio same high metres

Beath High School - Int 1 Physics14 Television high frequency waves

Beath High School - Int 1 Physics15 Each television station transmits a d _ _ _ _ _ _ _ _ frequency. Television different The following table shows some of the well known television stations and frequencies they use in one area of Scotland.

Beath High School - Int 1 Physics16 Aerial Parts of a television receiver tuner Sound decoder Vision decoder Sound amplifier Vision amplifier loudspeakerPicture tube

Beath High School - Int 1 Physics17 - The aerial detects many r _ _ _ _ signals and changes them into e _ _ _ _ _ _ _ _ signals. - The t _ _ _ _ selects the signal you want. (i.e. the ch _ _ _ _ _ of your choice) - The decoders separate the sound and vision signals from the c _ _ _ _ _ _ wave. Parts of a television receiver radio Aerial tuner Sound decoder Vision decoder electrical tuner channel carrier

Beath High School - Int 1 Physics18 - The amplifiers make the electrical s _ _ _ _ _ _ stronger. One amplifier is for the s _ _ _ _ signal and the other amplifier is for the p _ _ _ _ _ _ signal. - The l _ _ _ _ _ _ _ _ _ _ changes the audio signal into a sound wave, - The p _ _ _ _ _ _ t _ _ _ changes the video signal into pictures. Parts of a television receiver signals Sound amplifier Vision amplifier loudspeakerPicture tube sound picture loudspeaker picture tube

Beath High School - Int 1 Physics19 In a colour television only t _ _ _ _ colours can be produced on the screen. The three colours are R _ _, G _ _ _ _ and B _ _ _. All the other colours are produced by m _ _ _ _ _ these three colours. When RED, GREEN and BLUE are all mixed together W _ _ _ _ is produced. three Television – Colour pictures Red,Green Blue. mixing WHITE

Beath High School - Int 1 Physics20 Any colour can be made by mixing the l _ _ _ _ of these colours. You can remember the order of colours in the "star" by remembering the following: light Television – Colour pictures Rich Young Girls Can Buy Meals R _ _ Y _ _ _ _ _ G _ _ _ _ C _ _ _ B _ _ _ M _ _ _ _ _ _ RedYellowGreenCyanBlueMagenta

Beath High School - Int 1 Physics21 RED + GREEN = Y _ _ _ _ _ GREEN + BLUE = C _ _ _ _ BLUE + RED = M _ _ _ _ _ _ YELLOW Television – Colour pictures CYAN MAGENTA

Beath High School - Int 1 Physics22 Intermediate 1 Physics Telecommunication Satellites

Beath High School - Int 1 Physics23 Radio waves can be sent around the w _ _ _ _ via satellites. For example, the American Superbowl competition can be seen l _ _ _ in the U.K. because of the signal being passed on by s _ _ _ _ _ _ _ _. world Satellites live satellite.

Beath High School - Int 1 Physics24 Modern satellites can beam various signals back to the ground. For example: T.V. p _ _ _ _ _ _ _ _ _ p _ _ _ _ calls w _ _ _ _ _ _ pictures t _ _ _ _ _ _ _ stolen cars. The satellites o _ _ _ _ the earth and t _ _ _ _ _ _ _ signals to or r _ _ _ _ _ _ signals from ground stations. programmes Uses of satellites phone weather tracking orbit transmit receive

Beath High School - Int 1 Physics25 A Geostationary satellite always remains above the s _ _ _ point of the Equator on the Earth's surface. The dish on the ground can be set to receive a strong signal and not be m _ _ _ _ again. same Geostationary satellites moved

Beath High School - Int 1 Physics26 Geostationary SatellitesOrbits once every _ _ hours Orbits above the E _ _ _ _ _ _. 24 Geostationary satellites Other SatellitesSeveral orbits completed every 24 hours. Height is l _ _ _ than that of Geostationary satellites. Equator. less

Beath High School - Int 1 Physics27 The signals from satellites travel great distances and a bare aerial cannot pick up a s _ _ _ _ _ e _ _ _ _ _ signal. A curved reflector can bring radio waves to a f _ _ _ _ just like curved mirrors cause l _ _ _ _ rays to meet at the focus. strong enough Curved Reflectors focus light

Beath High School - Int 1 Physics28 Ray diagram showing how radio waves are brought to a f _ _ _ _ by a c _ _ _ _ _ r _ _ _ _ _ _ _ _. focus Curved Reflectors curved reflector.

Beath High School - Int 1 Physics29 Aerial placed at the f _ _ _ _ focus Curved Reflectors C _ _ _ _ _ reflector receiver Curved

Beath High School - Int 1 Physics30 A strong/weak radio signal can be detected if the aerial is positioned at the focus of the curved reflector. More/Less of the wave energy is collected when these aerials are used. (This is because the dish collects more/less of the energy in the wave than a bare aerial. Also its curved shape f _ _ _ _ _ _ the collected energy on to the aerial.) focuses Curved Reflectors

Beath High School - Int 1 Physics31 Very large dish aerials are used to detect radio waves from distant stars. These detectors are called r _ _ _ _ t _ _ _ _ _ _ _ _ _. radio Curved Reflectors telescopes.

Beath High School - Int 1 Physics32 Intermediate 1 Physics Telecommunication Optical fibres

Beath High School - Int 1 Physics33 We can look at our r _ _ _ _ _ _ _ _ _ in a mirror or the light from any shiny object being reflected. The angles i and r are the s _ _ _ size. reflection Reflection r the angle of reflection same

Beath High School - Int 1 Physics34 At one time signals always were sent through copper w _ _ _ _. An e _ _ _ _ _ _ _ _ _ current flows through the phone lines but e _ _ _ _ _ is lost and the signal needs to be boosted every so often at repeater stations. An optical fibre is a very t _ _ _ piece of flexible g _ _ _ _ which can carry l _ _ _ _ energy. The light is r _ _ _ _ _ _ _ _ between the sides of the optical fibre. wires. Optical fibres electrical energy thin glass light reflected

Beath High School - Int 1 Physics35 In air, light travels at the s _ _ _ speed as radio waves, _ _ _ million metres per second. In optical fibres, the light travels slightly s _ _ _ _ _ at 200 million metres per second. same Optical fibres 300 slower

Beath High School - Int 1 Physics36 More and more people are receiving signals into their homes which have come through optical f _ _ _ _ _, for example: cable t _ _ _ _ _ _ _ _ _ p _ _ _ _ calls h _ _ _ banking I _ _ _ _ _ _ _ access fibres, Uses of optical fibres television phone home Internet

Beath High School - Int 1 Physics37 One disadvantage of using optical fibres is the inconvenience of having to lay the cables u _ _ _ _ _ _ _ _ _ _ which means digging trenches along the pavements. One advantage is not having to install a satellite d _ _ _ on the wall of the house. Another advantage is that the reception is not affected by b _ _ weather conditions, e.g. heavy s _ _ _. underground Uses of optical fibres dish bad snow.

Beath High School - Int 1 Physics38 Comparison of Copper cable and Optical Fibre: Optical fibres Copper CableOptical Fibre Repeater stations every 4 km Repeater stations every 1 _ _ km conversations at a time conversations at a time Thick and heavyT _ _ _ and very l _ _ _ _ Almost 300 million metres per second _ _ _ million metres per second Thin 100 light

Beath High School - Int 1 Physics39 Intermediate 1 Physics Telecommunication Telephone

Beath High School - Int 1 Physics40 People can speak to each other, over l _ _ _ distances, by telephone. Speech is changed into an e _ _ _ _ _ _ _ _ _ signal and changed back into s _ _ _ _ again at the receiver. Telephone long electrical sound m………….l..…………. MouthpieceEarpiece Sound T…………..R…………. Link:copper wire Carrier: electrical signal microphone loudspeaker TransmitterReceiver

Beath High School - Int 1 Physics41 Telephone PartEnergy Change Sound to electrical Electrical to sound microphone loudspeaker

Beath High School - Int 1 Physics42 Phones can be connected by copper w _ _ _ or optical f _ _ _ _ (shown below). Telephone wire microphoneloudspeaker M………….E…………. Sound TransmitterReceiver Link: o……. f……. Carrier: l……. signal Mouthpiece Earpiece Carrier: light signal fibre Link: optical fibre

Beath High School - Int 1 Physics43 Mobile phones rely on r _ _ _ _ signals travelling from the transmitter to the r _ _ _ _ _ _ _. These signals carry Mobile phones radio Carrier: r……. w….. microphoneloudspeaker MouthpieceEarpiece Sound TransmitterReceiver Link: no physical link Carrier: radio wave receiver. the message through air without wires. A mobile phone has to be a combined radio t _ _ _ _ _ _ _ _ _ _ and receiver. transmitter

Beath High School - Int 1 Physics44 There are advantages and disadvantages to using a mobile phone. You do not have to find a phone box when you want to make an urgent call. However, some drivers cause a _ _ _ _ _ _ _ _ when they use a m _ _ _ _ _ phone and drive at the same time. Mobile phones accidents mobile

Beath High School - Int 1 Physics45 Some locations prevent you using the mobile phone, for example: in the Scottish H _ _ _ _ _ _ _ _ (the hills s _ _ _ the signal) inside l _ _ _ tunnels. Mobile phones Highlands stop long

Beath High School - Int 1 Physics46 Mouthpiece A mouthpiece transmits the message. S _ _ _ _ energy enters the m _ _ _ _ _ _ _ _ _ and is changed into electrical e _ _ _ _ _. Energy changes in a telephone system Sound mouthpiece energy

Beath High School - Int 1 Physics47 Earpiece An earpiece receives the message. Electrical energy is changed back to s _ _ _ _ in the loudspeaker. Energy changes in a telephone system sound

Beath High School - Int 1 Physics48 Telephone signals Copper wires carry the message in the form of an e _ _ _ _ _ _ _ c _ _ _ _ _ _, which travels at almost _ _ _ million metres per second. Energy changes in a telephone system electric current 300

Beath High School - Int 1 Physics49 Fax Fax is the shortened term for f _ _ _ _ _ _ _ _. A document is inserted into the machine and a c _ _ _ of the document is received at the other end of the p _ _ _ _ line. Important documents can be transferred very q _ _ _ _ _ _. Before this invention, documents had to go by p _ _ _. facsimile. copy phone quickly. post.

Beath High School - Int 1 Physics50 The signal in a phone line can be displayed on the screen of an oscilloscope. The v _ _ _ _ _ _ of the signal varies as the caller speaks into the mouthpiece. Oscilloscope patterns voltage

Beath High School - Int 1 Physics51 Loudness Loud sounds produce a h _ _ _ _ _ voltage signal than a quiet soft sound. The a _ _ _ _ _ _ _ _ is greater for high voltages. Oscilloscope patterns higher amplitude smaller

Beath High School - Int 1 Physics52 Frequency Some sounds have a higher pitch (frequency) than others. For example, sound ‘A’ below could be a horn which produces a l _ _ pitched sound. Sound ‘B’ below could be a whistle which produces a high p _ _ _ _ _ _ s _ _ _ _. Oscilloscope patterns low pitched sound. high frequency

Beath High School - Int 1 Physics53 The oscilloscope can display waves of different frequencies. A high frequency wave produces m _ _ _ waves per second than low a frequency wave. Oscilloscope patterns more

Beath High School - Int 1 Physics54 Intermediate 1 Physics Telecommunication End of Unit