Broadcast standards

Unit 21: Understanding Video Technology


1. Television Standards

NTSC, PAL and SECAM are all television standards for analogue television. PAL is most used in the UK, Germany and Eastern Europe. SECAM is used in France, Russia and a few other countries. NTSC is used in the US, Canada and parts of South America.

These analogue system have now largely been replaced with digital terrestrial systems. Digital systems have advantages over analogue systems in that they have more capacity for data, lower operating costs and a better quality of picture. 

Digital

Advantages:
Better resolution 
Narrower bandwidth signal transmission

More compatible with modern technology such as computers, DVDs, Blu-Ray, and modern video processors in TVsMore precise, sharper, less blurry for higher resolutions

Disadvantages:
Difficult to modulate, digital tuners more expensive than analog
Limited color range 
Not backwards-compatible with older technology 
Easy to manipulate
Flexible
Compatibility with other analogue systems
Easy internet connection 

More reliable
pixelating, and can freeze up (buffering)


Analogue 

Advantages:
Less expensive
Digital communications require greater bandwidth than analogue to transmit the same information.


Disadvantages:
Uses less bandwidth
Worse quality 





PAL




 In 1962 Walter Burch created PAL to keep up with the rapidly introduced colour television. PAL, short for Phase Alternating Line, is a colour encoding system for analogue television and is used in the UK today.  

Description	English: Oscilogram of PAL signal - 2 lines.
Date	1 December 2008 (original upload date)
Source	Transferred from en.wikipedia to Commons by Plrk using CommonsHelper.
Author	Markome at English Wikipedia

The name "Phase Alternating Line" describes the way that the phase of part of the colour information on the video signal is reversed with each line, which automatically corrects phase errors in the transmission of the signal by cancelling them out, at the expense of vertical frame colour resolution





(fps 25, 50 htz)
(Pal Signal)

Advantages and disadvantages of PAL
Advantages:
Adopted by most of Europe
Modification of NTSC to avoid colour distortion
Higher number of scan lines than NTSC
Higher gamma ratio than NTSC

Disadvantages:
Only runs at 25 frames per second (the lower the frame rate the worse for fast motion and more flicker)
Visibly colour saturation
Variable colour saturation



SECAM 

                                                                                       SECAM was developed in 1956 by soviet technicians. The first proposed system was called SECAM I in 1961, followed by other studies to improve compatibility and image quality. The first color television sets cost 5000 Francs. Colour TV was not very popular initially; only about 1500 people watched the inaugural program in colour. A year later, only 200,000 sets had been sold of an expected million. This pattern was similar to the earlier slow build-up of colour television popularity in the USA.

Short for Sequential Colour with Memory, SECAM is a colour TV standard that was introduced in the early 1960 in France. SECAM uses the same resolution as PAL(625 lines) but transmits the colour information slightly differently. 
(Fps 30)

(Broadcast systems in different countries)


Advantages and disadvantages of SECAM
Advantages:
Uses an FM frequency  - therefore less errors
Lower cost than NTSC and PAL
Higher number of scan lines than NTSC and PAL

Disadvantages:
Not suitable for studio use
Half the colour information is lost on each line

NTSC



National Television System Committee or NTSC is the analogue television system used in most of Northern and Southern America. 

NTSC colour encoding is used with the system television signal, which consists of 29.97 frames per second . Each frame is composed of two fields, each consisting of 262.5 scan lines, for a total of 525 scan lines. 

Original NTSC colorimetry (1953)	CIE 1931 x	CIE 1931 y
primary red	0.67	0.33
primary green	0.21	0.71
primary blue	0.14	0.08
white point (CIE Standard illuminant C)	0.310	0.316

After nearly 70 years of use, the vast majority of over-the-air NTSC transmissions in the United States were turned off on June 12, 2009, and August 31, 2011, in Canada and most other NTSC markets


(fps 29, 60htz)

Advantages and disadvantages of NTSC
Advantages:
Runs at nearly 30 frames per second (good for fast motion as the higher the frame rate the better, smoother the action appears and reduces visible flicker)
Has simpler circuits than PAL and SECAM
Has a less obvious picture noise
Is less costly than PAL

Disadvantages:
Small signal bandwidth which increases likelihood of interference
More costly than SECAM
Lower number of scan lines which reduces the quality on a large picture

2. Broadcasting Systems

Types of Television / ways to watch



Cable 
                                                          
Cable television previously known as Community Antenna Television or CATV originated in Pennsylvania in 1948.
Virgin media and BT broadband TV are 2 examples of cable TV. Many cable companies have upgraded to digital cable in the last 5 years but Virgin and BT have not as they both maintain a very fast connection. Fibre-optic cable provides the fastest internet and TV connection on the market at the moment which is one of the one of the major advantages to having cable. It's by far the quickest. 



Advantages and disadvantages of Cable
Advantages:
Fast
Connection very rarely lost

Disadvantages:
Cost

Digital 

Digital TV originated in 1938 in the UK when towns such as Bristol used wires to carry television signals to homes which could not receive signals over the air.
Digital television is the transmission  and video  multiplexed signal, in contrast to the totally analog and channel separated signals used by analogue. An example of this is a freeview box.  The advantages of most digital TV systems is that after the initial payment for the box it is free which is why its still the most popular TV in the UK at the moment. 

Advantages and disadvantages of Digital
Advantages:
Free after the initial cost of the box

Disadvantages:
Fewer channels than SKY
Cannot receive box office channels

Satellite 




Satellite TV works by launching a satellite into orbit. This technique revolutionised popular entertainment and sparked an explosion in technological development.
Three years after the satellite was first introduced in 1965 it was used to show pictures of the moon  which were broadcast into people's homes.
Sky is an example of a satellite TV station. It works with the addition of a satellite dish which is attached to the edge of your house, a reviver near your tv then picks up the signal. the reviver then has a wire from it which then connects to your television allowing you to watch fast live tv. 




Advantages and disadvantages of SKY
Advantages:
Thousands of channels to choose from
A wide variety of box office channels

Disadvantages:
Monthly cost
Monthly costs can increase and extra cost for special programmes such as sporting events

Internet 



Before 2006 there was no catch up services which allowed viewers to watch programmes at their convenience but now this is part of modern life.
Nexflix, BBC iplayer and 4OD are examples of internet television. Internet TV is usually a catch up service offering showings of programs from the last week. This is what i think will soon take over in an internet dominated world its only a matter of time until everyone is watching globe TV through the internet on a television set. There are also services such as youtube and Vimeo which allow a viewer to browse  through millions of videos to find exactly what there looking for. 

  
Advantages and disadvantages of internet
Advantages:
Can watch at your own convenience and at times to suit you i,e, available on demand

Disadvantages:

WIFI is not 100% reliable and the connection can be lost

Neflix and similar services charge a monthly fee

6. Cables

Types of cables 





















































Component cable

• The all-in-one solution for high-definition and standard TVs
• High-definition gaming output of 720p or 1080i
• Progressive-scan DVD playback in 480p
• Dolby Digital 5.1 Surround Sound output
• Component (Y, Pr, Pb) high definition video output
• Usually about 8ft long 

These cables have been very common through out my lifetime but now they are slowly being replaced by the feaster and easier to use HDMI cables which are now used for all HD thing Including gaming. 

Composite Cable 

• 
  
• Color-coded connectors help simplify identification and installation.
• Connectivity : 3 RCA male (yellow, red and white) to RCA male
• Length : 5 feet (1.5 meter)

Transmits analog audio and composite video signals between devices such as televisions, satellite or cable receivers, VCRs, game console systems, speakers and more and usually comes with a red white and yellow cable which if not is only an audio cable. 

HDMI 

• Broadcast quality digital video, digital audio, and inter-component control signals all in one compact, high-performance connection
• Supports uncompressed audio/video signals
• Fully HDCP compliant to Provide highest level of signal quality
• Fully HDCP compliant to Provide highest level of signal quality
• Perfect for both high-definition video and standard video formats.

One of the most common cables around today and its used fro everything from Blu-ray to Xbox anything that requires an HD connection. 

Audio Jack 


Connect portable devices such as MP3 players to an amplifier/radio with a 3.5mm in port. Suitable for your In Car Sound system Fits all ipods, iphones Multimedia speakers, and Mp3 playes with a 3.5mm jack















S-Video




SVHS (also known as S-Video) plug (4 pins) to plug (4 pins). 

Carries video only (no sound). Results in better quality than composite cables. 
Standard now on most TV s and other visual devices (DVD players, camcorders, projectors) and now on most computers (as TV-Out or Video-In). 
In many European Union countries, S-Video is less common because of the dominance of the very well known and widely uses SCART cable which soon took over and gained world dominance because of its ability to transmit Sound 





DVI cabledigital Visual Interface (DVI)

DVI stands for Digital Video Interface; this type of cable is also used like an HDMI cable for high-definition television, DVD players, and game consoles such as an Xbox 360. Now that HDMI cables have become more of the standard and one sod the worlds most popular cables  used for HD television, DVI's are mostly used for computer connections, though they are still used to connect televisions to other components.

VGA

VGA (Video Graphics Array) originally intended computers in the 1980s though, now it has come to mean any cable or port with a VGA connector. It has a 15 pin connection and fits with most computer monitors today. . In addition, you will find VGA ports on many newer televisions so you can connect your computer to your TVs which enables a person to connect there laptop or computer to the TV to make the most of  a bigger screen. 

Mini-VGA

• Mini DisplayPort 1.1a compliant receiver offering 5.4 Gbps bandwidth over 2 lines
• Integrated triple 10-bit, 162 MHz video DAC for analog VGA signal output
• Supports up to 1080p, 1920 x 1200 reduced blanking video resolution

The Mini DVI to VGA display adapter for connecting Macs or some PCs such a s ones made by sony equipped with a DVI port to an external VGA monitor or projector at home.