From Radio Waves to Internet Streaming: An introduction to broadcast technology.
The definition of Broadcasting is “To sow over a wide area…” In Broadcast technology this means communicating over television or radio to an audience ,using video and audio transmission. The main methods of television broadcasting are:
- VOD (Video On Demand)
Analogue uses electromagnetic waves which are a type of energy, electromagnetic waves can carry information as they move which can be used to transfer information from one point to another. Electromagnetic waves are a type of radiation which can vary in size e.g radio waves, light waves and X-rays. It is with radio waves that broadcasters are able to transfer information.
Broadcasters can use radio waves to transfer their programmes to a viewers television. Analogue works by sending the information as radio waves from a transmitter(towers/masts) to a receiver(aerials). The receiver catches the signal from the transmitter and sends it down a wire to the TV. TV channels are tuned in on the TV according to their frequency. The 2 main frequencies employed by analogue are UHF(Ultra High Frequency) and VHF(Very High Frequency).
The information is sent as variations in the amplitude, frequency and phase of the electromagnetic signal. This simply means the TV programe is sent over Radio waves from a TV mast to the aerial on top of your home(or where ever it is).
Terrestrial Broadcast History
1929 BBC begins Broadcasting “over the Air”.
1961 a conference in Stockholm (ST61) gives each European country its own frequency to broadcast its programmes.
1985: UK stops using VHF to broadcast.
2010 – 2012 UK digital switchover takes effect, all terrestrial broadcasting in the EU is set to end in 2012.
Cheap, able to broadcast to both local and national audiences, can serve a variety of different reception modes like Handheld, Aerial on house or TV, Transmission quality stays the same regardless of the size of the audience.
limited interactivity, line of sight obstructions can weaken the signal strength, Takes up a considerable airspace which puts it at odds with other broadband users, Image quality can suffer “ghosting”.
So in the future of Broadcasting terrestrial will no longer exist as the digital age has come.
Cable is a method of broadcasting where the Programme’s information is transmitted by cables rather than through the air. The transmission begins at a head end facility which is the programmes are processed and then transmitted down a large coaxial cable, which is named a Trunk Cable, which runs through the middle of a town or city. Feeder cables break off from the Trunk cable kind of like a tree’s roots and take the signal into a neighborhood, Drop cables then branch off from the Feeder cables and carry the signal into a set top box or cable modem which processes the signal. This is then sent to the TV along a video connector.
Cable Broadcast History
CATV(Community Antenna Television) is often used to mean “Cable TV”. Cable TV originated from 1948 when certain areas were out of terrestrial broadcast range or couldn’t get a good signal so these big antennas were made that used cables to feed the signals into homes.
Cable in most common in North America, Europe, Australia and East Asia.
Reliability is a factor as it can deliver signals where dishes cant e.g mountainous areas.
Lightwave and Fibre-optic Cables provide on demand and interactive services.
“Lossy” signal. This means that parts of the sound and picture could be lost over a certain difference. Because of this many companies have had to install Signal Amplifiers at half-mile intervals to boost the signals strength and thats going to cost alot of money. Because of the expense many companies have switched to Lightwave signals which travel down a fibre-optic cable which goes straight to a node in a neighborhood. The Node will then convert the signal to an RF signal which gives a stronger signal strength which reduces signal distortion and noise.
Overall Cable TV is still popular today and one of the most popular Cable providers in the UK is Virgin Media.
Satellite works by transmitting signals to uplink dishes, which transmit the electromagnetic signal to a specific satellite high in the planets orbit. The Satellite then transmits the signal back down to the Earth on a different frequency which is caught by a Parabolic dish on the customers home. The Dish amplifies the signal which has become after traveling tens of thousands of miles, the signal is then sent down a cable to a receiver e.g Sky Box. The Signal is then taken to from the receiver to the TV by a video connector.
History of Satellite Broadcasting
In 1976 the first hints of Satellite TV emerged in the form of a broadcast of the heavyweight boxing match called the “Thriller from Manilla” which was broadcast through Satellites.
Satellite TV truly came into being during the 80’s and was initially very expensive, gradually the price went down throughout the 80’s.
In the 90’s four cable companies launched a DBS (Direct Broadcast Satellite) named Primestar which kick started the small Satellite dish era.
Recently the number of Satellite TV subscribers has reach more than 18 million and its still growing.
It offers a lot of Channels, Companies are very competitive so a lot of companies offer free installation and low fees. Portable uplinks
The Satellites cost a considerable amount of money to maintain and provide for. Subscription and Installation Fees. Atmospheric interference. Signal Strength.
According to many Digital is seen as the future of Broadcasting. It can be sent by Cable, Satellite and Terrestrial(over the air). The Information is encoded as an “MPEG transport stream” which includes both audio and video data, It also contains error correction information and provides a higher picture quality than any Analogue signal. DVB-T is the European standard for Digital TV.
History of Digital Broadcasting
Digital is an emerging form of broadcasting and will soon be taking over Britain and most of Europe in the “Digital Switchover”.
Digital signals are better than Analogue because they take up less bandwidth which means there is more room available for other information and interactive services, another thing is the way that the signal is packaged should also mean it will not be as “Lossy” as an Analogue signal would be.
It costs a lot money to switch over from Analogue to Digital, Cliff effect which means if the signal degrades beyond a certain point the receiver will not be able to decode the signal. Switching channels is slower because of time delays in the decoding of the signal. You may require extra equipment and a new antenna.
VOD (Video On Demand)
VOD is used to download and/or stream videos to a computer or a similar device so people can watch them whenever they want.
It is new way to broadcast films and TV to an audience digitally when they want it, It is quickly catching on.
VOD gives the viewers full control of what they watch and when, some are free such as BBC iPlayer and others charge like Netflix and Zune.
VOD is also known as internet TV, which is also referred to as “Catch up TV” it is a way of broadcasting TV programes over an internet connection. The viewers have the choice of either Stream programmes or Download them directly onto their PC or other device. Among the most popular internet TV providers are BBC iPlayer, 4OD and 5 on Demand.
4OD for an example is an internet broadcast service that offers Streams and Downloads of programmes from Channel 4, E4 and More 4 for 7 – 30 days after they are first broadcast, 4OD operates on Windows (XP, Vista, 7) Mac OS X and Linux and is available at channel4.com, Virgin media, Talktalk TV, BT vision, Playstation 3 and iPAD although the number of days the programmes are available may differ between them.
According to http://www.rapidtvnews.com Channel 4 recently (at this time of writing 14th November) reported that the number of 4OD users had gone up by 2 million and has shown a continued rise in viewing across all platforms from the 31 million recorded in the previous month, Hollyoaks is ahead in the popularity charts with 2.3 million views.
In general http://thenextweb.com reported “Visits to online video sites grew by over a third in the uk over the past year, with 785 million visits to websites such as youtube in september alone”.
People have been interested in the idea of Internet TV ever since the creation of modern internet but it never came to be until now when the technology has caught up with Idea and subsequently boomed.
Streaming is when a video is converted into a specific code that is put into a container bitstream which is them streamed continuously to a client computer(Audience).
Choice the viewer is given free reign to choose whatever they want to watch at any time, It’s free, Accessiblility is not a problem as it can be viewed on trains, boats and planes.
Loss of Advertising means they take a hit to the Broadcast provider’s revenue as people would rather have something for free than have adverts. You need a large bandwidth otherwise the progame could become disrupted by loss of connection, only recently have large Bandwidths become readily available. It will cost money to Set up, Run and Maintain in order to keep up with consumer demand. Illegal torrents will rob them of their profits, sites like tvlinks and surfthechannel are examples of torrent sites.
Based on the way the television Industry is heading its seems like Digital is becoming the dominant broadcasting service. The Digital switchover which is occurring in Britain and is scheduled to end on the 24th of October 2012. However consumers are becoming more and more keen on VOD (Video On Demand) which allows them to watch what they want when and where they want. This is good news for the consumers but not so great for the advertisers whom rely on revenue from broadcast advertising.