INDUSTRIAL TRAINING REPORT

DOORDARSHAN KENDRA PATNA

TRAINING PERIOD :- 04/06/12 TO 01/07/12 SUBMITTED BY:- MD EJAZ MOBASHIR INTEGRAL UNIVERSITY LUCKNOW, U.P DDK REG. NO:-362

ACKNOWLEDGMENT

I do take it pleasure to express my deepest sense of gratitude and respect to our eminent and most dynamic person Mr. S.R.F YUSUF(A.S.E) for their affectionate guidance and kind support through out my training in the department.

It was my great pleasure to start my training under the expert guidance and able supervision of most esteemed and qualified person Mr. N.K.SINGH who gave me full cooperation and suggestion.So I am extremely grateful to both of them.

I am greatly indebted to rest all engineering operative and employee of DDK PATNA who gave me full cooperation providing all facilities and all sorts of help in connection with in plant training at DDK PATNA.

CONTENT

1) INTRODUCTION

2) TELEVISION STANDARD

3) TELEVISION PRINCIPLE AND SCANNING

4) COLOUR COMPOSITE VIDEO SIGNAL

5) TELEVISION STUDIO

6) COLOUR TEMPERATURE

7) SATELLITE COMMUNICATIOM a)EARTH STATION b)UPLINK & DOWNLINK c)TRANSMITTER

8)HDTV

INT RODUCTION Doordarshan

Type Broadcast , radio, television

network and online

Country India

Availability Nationwide

Founded by   Government of India   in 1959

Motto Satyam Shivam Sundaram

Headquarters New Delhi ,   Delhi , India ,

Owner Prasar Bharati

Key people Prof. Amukurajah Das,   CEO

Launch   date 15 September 1959

Former   names All India Radio

Picture format 480i   ( 16:9   SDTV ) 720p   ( HDTV )

Official website www.ddindia.gov.in

DOORDARSHAN (Hindi: दूरदर्श�न; literally Distant Show) is an Indian public service broadcaster, a division of Prasar Bharati. It is one of the largest broadcasting organizations in India in terms of the infrastructure of studios and transmitters. Recently, it has also started Digital Terrestrial Transmitters. On September 15, 2009, Doordarshan celebrated its 50th anniversary. The DD provides television, radio, online and mobile services

throughout metropolitan and regional India, as well as overseas through the Indian Network and Radio India

Doordarshan had a modest beginning with the experimental telecast starting in Delhi on 15 September 1959 with a small transmitter and a makeshift studio. The regular daily transmission started in 1965 as a part of All India Radio. The television service was extended to Bombay (now Mumbai) and Amritsar in 1972. Up until 1975, only seven Indian cities had a television service and Doordarshan remained the sole provider of television in India. Television services were separated from radio in April 1 1976 Each office of All India Radio and Doordarshan were placed under the management of two separate Director Generals in New Delhi. Finally, in 1982, Doordarshan as a National Broadcaster came into existence.

National telecasts were introduced in 1982. In the same year, colour TV was introduced in the Indian market with the live telecast of the Independence Day speech by then prime minister Indira Gandhi on 15 August 1982, followed by the 1982 Asian Games which were held in Delhi. Now more than 90 percent of the Indian population can receive Doordarshan (DD National) programmes through a network of nearly 1,400 terrestrial transmitters. There are about 46 Doordarshan studios producing TV programmes today

Presently, Doordarshan operates 21 channels – two All India channels - DD National and DD News, 11 Regional language Satellite Channels (RLSC), four State Networks (SN), an International channel, a Sports Channel DD Sports and two channels Rajya Sabha TV & DD-Lok Sabha for live broadcast of parliamentary proceedings.On DD National (DD-1), Regional programmes and Local Programmes are carried on time-sharing basis. DD News channel, launched on 3 November 2003, which replaced the DD Metro (DD-2)Entertainment channel, provides 24-Hour news service.The Regional Languages Satellite channels have two components – The Regional service for the particular state relayed by all terrestrial transmitters in the state and additional programmes in the Regional Language in prime time and non-prime time available only through cable operators. DD-Sports Channel is exclusively devoted to the broadcasting of sporting events of national and international importance. This is the only Sports Channels which telecasts rural sports like Kho-Kho, Kabbadi etc. something which private broadcasters will not attempt to telecast as it will not attract any revenues.

EARLY NATIONAL PROGRAMMING:-

The 80s were noted for Hum Log (1984), Buniyaad (1986–87) and comedy shows like Yeh Jo Hai Zindagi (1984).

Hum Log , Buniyaad, and Nukkad along with mythological dramas such as Ramayan (1987–88) and Mahabharat (1989–90), Shaktimaan, India's First Superhero, glued millions to Doordarshan as did shows such as Bharat Ek Khoj, The Sword of Tipu Sultan and The Great Maratha.

Hindi film songs based programmes like Chitrahaar, Rangoli, Ek Se Badkar Ek and Superhit Muqabla.

Crime thrillers like Barrister Vinod (starring Parikshit Sahni), Karamchand (starring Pankaj Kapoor), Aparadhi Kaun, PC 1008 (starring Kanwaljeet), Police File Se, Byomkesh Bakshi (starring Rajit Kapoor), Reporter (Shekhar Suman), Tehkikaat and Janki Jasoos, Suraag (starring Sudesh Berry).

Shows targeted at children include Faerie Tale Theatre, Dada Dadi ki Kahaniyan, Vikram Betaal, Space City Sigma, Stone Boy, Malgudi Days, Tenali Rama, Potli Baba Ki (puppet show), He-Man, Superhuman Samurai Cyber Squad, Knight Rider, Teletubbies, Street Hawk and a horror serial Kile ka Rahasya (1989).

Other popular shows include Oshin a Japanese drama series, Trishna[disambiguation needed], Mr. Yogi, Neem Ka Ped, Circus, Fauji (launching Shahrukh Khan), Rani Laxhmibai, Dastan-E-Hatim Tai, Alif Laila, Gul Gulshan Gulfam, Udaan, Rajani, Talaash[disambiguation needed], Phir Wohi Talash, Katha Saagar, Nupur, Mirza Ghalib, Wagle ki Duniya, Phulvanti, Sangharsh,Lifeline[disambiguation needed], Kashish (launching Malvika Tiwari), Srimaan Srimati, Tu Tu Mein Mein, Junoon[disambiguation needed], Ajnabi (starring Danny Denzongpa), Zabaan Sambhal Ke,Dekh Bhai Dekh, Sansaar, Swabhimaan, Chanakya, Shanti[disambiguation

needed] (launching Mandira Bedi), Sea Hawks[disambiguation needed] (starring R. Madhavan), Surabhi, Tana Bana, Mujrim Hazir (launching Navni Parihar), Jaspal Bhatti's Flop Show, Meri Awaaz Suno, Captain Vyom, and Chandrakanta and Tootne Ke Baad (TV Serial by Paigham Afaqui)

Not many remember but Doordarshan used to have serials before sponsored programmes came into existence. Serials like Dadi Maa Jagi, Bibi Natiyonwali, Aur Bhi Ghum Hai Zamane Mein, and Laddoo Singh Taxi Wala (starring Paintal) were also popular.

Sarab Sanji Gurbani was the first sponsored programme on Doordarshan, sponsored by Texla TV.

Doordarshan also telecast English cartoons at 12.00 noon during summer vacations in a programme named "Fun Time" which showed cartoons like Spider-Man, Giant Robo, Gayab Aaya,Guchhae, 

TELEVISION STANDARDS

There are three main television standards used throughout the world.

NTSC - National Television Standards Committee

Developed in the US and first used in 1954, NTSC is the oldest existing broadcast standard. It consists of 525 horizontal lines of display and 60 vertical lines. Only one type exists, known as NTSC M. It is sometimes irreverently referred to as "Never Twice the Same Color."

SECAM - Système Électronique pour Couleur avec Mèmoire. 

Developed in France and first used in 1967. It uses a 625-line vertical, 50-line horizontal display. Different types use different video bandwidth and audio carrier specifications. Types B and D are usually used for VHF. Types G, H, and K are used for UHF. Types I, N, M, K1 and L are used for both VHF and UHF. These different types are generally not compatible with one another. SECAM is sometimes irreverently referred to as "Something Essentially Contrary to the American Method" or "SEcond Color Always Magenta."

PAL - Phase Alternating Line

Developed in Germany and first used in 1967. A variant of NTSC, PAL uses a 625/50-line display. Different types use different video bandwidth and audio carrier specifications. Common types are B, G, and H. Less common types include D, I, K, N, and M. These different types are generally not compatible with one another. Proponents of PAL irreverently call it "Perfection At Last," while critics of its enormous circuit complexity call it "Pay A Lot" or "Picture Always Lousy.

TELEVISION STANDARD USED IN INDIA IS PAL.

PAL(PHASE ALTERNATING LINE):-PAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system. The articles on broadcast television systems and analogue television further describe frame rates, image resolution and audio modulation. For discussion of the 625-line / 50 field (25 frame) per second television standard.In the 1950s, the Western European countries commenced planning to introduce colour television, and were faced with the problem that the NTSC standard demonstrated several weaknesses, including colour tone shifting under poor transmission conditions. To overcome NTSC's shortcomings, alternative standards were devised, resulting in the development of the PAL and SECAM standards. The goal was to provide a colour TV standard for the European picture frequency of 50 fields per second (50 hertz), and finding a way to eliminate the problems with NTSC.PAL was developed by Walter Bruch at Telefunken in Germany. The format was unveiled in 1963, with the first broadcasts beginning in the United Kingdom and West Germany in 1967, the one BBC channel initially using the broadcast standard was BBC2 which had been the first UK TV service to introduce '625-lines' in 1964. Telefunken PALcolor 708T was the first PAL commercial TV set. It was followed by Loewe S 920 & F 900.Telefunken was later bought by the French electronics manufacturer Thomson. Thomson also bought the Compagnie Générale de Télévision where Henri de France developed SECAM, the first European Standard for colour television. Thomson, now called Technicolor SA, also owns the RCA brand and licenses it to other companies; Radio Corporation of America, the originator of that brand, created the NTSC colour TV standard before Thomson became involved.The term PAL is often used informally and somewhat imprecisely to refer to the 625-line/50 Hz television system in general, to differentiate from the 525-line/60 Hz system generally used with NTSC. Accordingly, DVDs are labelled as either PAL or NTSC (referring informally to the line count and frame rate) even though technically the discs do not have either PAL or NTSC composite colour. The line count and frame rate are defined as EIA 525/60 or CCIR 625/50; PAL and NTSC are only the method of embedding colour in the transmission.

COLOUR ENCODING:-

Both the PAL and the NTSC system use a quadrature amplitude modulated subcarrier carrying the chrominance information added to the luminance video signal to form a composite videobaseband signal. The frequency of this subcarrier is 4.43361875 MHz for PAL, compared to 3.579545 MHz for NTSC. The SECAM system, on the other hand, uses a frequency modulation scheme on its two line alternate colour subcarriers 4.25000 and 4.40625 MHz.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. Lines where the colour phase is reversed compared to NTSC are often called PAL or phase-alternation lines, which justifies one of the expansions of the acronym, while the other lines are called NTSC lines. Early PAL receivers relied on the human eye to do that cancelling; however, this resulted in a comb-like effect known as Hanover bars on larger phase errors. Thus, most receivers now use a chrominance delay line, which stores the received colour information on each line of display; an average of the colour information from the previous line and the current line is then used to drive the picture tube. The effect is that phase errors result in saturation changes, which are less objectionable than the equivalent hue changes of NTSC. A minor drawback is that the vertical colour resolution is poorer than the NTSC system's, but since the human eye also has a colour resolution that is much lower than its brightness resolution, this effect is not visible. In any case, NTSC, PAL, and SECAM all have chrominance bandwidth (horizontal colour detail) reduced greatly compared to the luminance signal.

Spectrum of a System I television channel with PAL

TELEVISION PRINCIPLES AND SCANNING

The earliest mechanical television systems used spinning disks with patterns of holes punched into the disc to "scan" an image. A similar disk reconstructed the image at the receiver. Synchronization of the receiver disc rotation was handled through sync pulses broadcast with the image information. However these mechanical systems were slow, the images were

dim and flickered severely, and the image resolution very low. Camera systems used similar spinning discs and required intensely bright illumination of the subject for the light detector to work.Analog television did not really begin as an industry until the development of the cathode-ray tube (CRT), which uses a steered electron beam to "write" lines of electrons across a phosphor coated surface. The electron beam could be swept across the screen much faster than any mechanical disc system, allowing for more closely spaced scan lines and much higher image resolution, while slow-fade phosphors removed image flicker effects. Also far less maintenance was required of an all-electronic system compared to a spinning disc system.

Displaying an imageA cathode-ray tube (CRT) television displays an image by scanning a beam of electrons across the screen in a pattern of horizontal lines known as a raster. At the end of each line the beam returns to the start of the next line; at the end of the last line it returns to the top of the screen. As it passes each point the intensity of the beam is varied, varying the luminance of that point. Acolor television system is identical except that an additional signal known as chrominance controls the color of the spot.Raster scanning is shown in a slightly simplified form below.

When analog television was developed, no affordable technology for storing any video signals existed; the luminance signal has to be generated and transmitted at the same time at which it is displayed on the CRT. It is therefore essential to keep the raster scanning in the camera (or other device

for producing the signal) in exact synchronization with the scanning in the television.The physics of the CRT require that a finite time interval be allowed for the spot to move back to the start of the next line (horizontal retrace) or the start of the screen (vertical retrace). The timing of the luminance signal must allow for this.The human eye has a characteristic called Persistence of vision. Quickly displaying successive scan images will allow the apparent illusion of smooth motion. Flickering of the image can be partially solved using a long persistence phosphor coating on the CRT, so that successive images fade slowly. However, slow phosphor has the negative side-effect of causing image smearing and blurring when there is a large amount of rapid on-screen motion occurring.The maximum frame rate depends on the bandwidth of the electronics and the transmission system, and the number of horizontal scan lines in the image. A frame rate of 25 or 30 hertz is a satisfactory compromise, while the process of interlacing two video fields of the picture per frame is used to build the image. This process doubles the apparent number of video fields per second and further reduces flicker and other defects in transmission.

Receiving signals:-

The television system for each country will specify a number of television channels within the UHF or VHF frequency ranges. A channel actually consists of two signals: the picture information is transmitted using amplitude modulation on one frequency, and the sound is transmitted with frequency modulation at a frequency at a fixed offset (typically 4.5 to 6 MHz) from the picture signal.The channel frequencies chosen represent a compromise between allowing enough bandwidth for video (and hence satisfactory picture resolution), and allowing enough channels to be packed into the available frequency band. In practice a technique called vestigial sideband is used to reduce the channel spacing, which would be at least twice the video bandwidth if pure AM was used.Signal reception is invariably done via a superheterodyne receiver: the first stage is a tuner which selects a television channel and frequency-shifts it to a fixed intermediate frequency (IF). The signal amplifier (from the microvolt range to fractions of a volt) performs amplification to the IF stages.

Extracting the sound:-At this point the IF signal consists of a video carrier wave at one frequency and the sound carrier at a fixed offset. A demodulator recovers the video signal and sound as an FM signal at the offset frequency (this is known as intercarrier sound).The FM sound carrier is then demodulated, amplified, and used to drive a loudspeaker. Until the advent of the NICAM and MTS systems, television sound transmissions were invariably monophonic.

COLOUR COMPOSITE VIDEO SIGNAL

The video carrier is demodulated to give a composite video signal; this contains luminance, chrominance and synchronization signals;[5] this is identical to the video signal format used by analog video devices such as VCRs or CCTV cameras. Note that the RF signal modulation is inverted compared to the conventional AM: the minimum video signal level corresponds to maximum carrier amplitude, and vice versa. The carrier is never shut off altogether; this is to ensure that intercarrier sound

demodulation can still occur.

Each line of the displayed image is transmitted using a signal as shown above. The same basic format (with minor differences mainly related to timing and the encoding of color) is used for PAL,NTSC and SECAM television systems. A monochrome signal is identical to a color one, with the exception that the elements shown in color in the diagram (the color burst, and the chrominance signal) are not present.The front porch is a brief (about 1.5 microsecond) period inserted between the end of each transmitted line of picture and the leading edge of the next line sync pulse. Its purpose was to allow voltage levels to stabilise in older televisions, preventing interference between picture lines. The front porch is the first component of the horizontal blanking interval which also contains the horizontal sync pulse and the back porch. The back porch is the portion of each scan line between the end (rising edge) of the horizontal sync pulse and the start of active video. It is used to restore the black level (300 mV.) reference in analog video. In signal processing terms, it compensates for the fall time and settling time following the sync pulse. In color television systems such as PAL and NTSC, this period also includes the colorburst signal. In the SECAM system it contains the reference subcarrier for each consecutive color difference signal in order to set the zero-color reference.

In some professional systems, particularly satellite links between locations, the audio is embedded within the back porch of the video signal, to save the cost of renting a second channel.

Monochrome video signal extraction:-The luminance component of a composite video signal varies between 0 V and approximately 0.7 V above the "black" level. In the NTSC system, there is a blanking signal level used during the front porch and back porch, and a black signal level 75 mV above it; in PAL and SECAM these are identical.In a monochrome receiver the luminance signal is amplified to drive the control grid in the electron gun of the CRT. This changes the intensity of the electron beam and therefore the brightness of the spot being scanned. Brightness and contrast controls determine the DC shift and amplification, respectively.

Color video signal extraction:-

A color signal conveys picture information for each of the red, green, and blue components of an image (see the article on Color space for more information). However, these are not simply transmitted as three separate signals, because:

Such a signal would not be compatible with monochrome receivers (an important consideration when color broadcasting was first introduced);

it would occupy three times the bandwidth of existing television, requiring a decrease in the number of television channels available; and,

typical problems with signal transmission (such as differing received signal levels between different colors) would produce unpleasant side effects.

Instead, the RGB signals are converted into YUV form, where the Y signal represents the overall brightness, and can be transmitted as the luminance signal. This ensures a monochrome receiver will display a correct picture. The U and V signals are the difference between the Y signal and the B and R signals respectively. The U signal then represents how "blue" the color is, and the V signal how "red" it is. The advantage of this scheme is that the U and V signals are zero when the picture has no color content. Since the human eye is more sensitive to errors in luminance than in color, the U and V signals can be transmitted in a relatively lossy (specifically: bandwidth-

limited) way with acceptable results. The G signal is not transmitted in the YUV system, but rather it is recovered electronically at the receiving end.In the NTSC and PAL color systems, U and V are transmitted by adding a color subcarrier to the composite video signal, and using quadrature amplitude modulation on it. For NTSC, the subcarrier is usually at about 3.58 MHz, but for the PAL system it is at about 4.43 MHz. These frequencies are within the luminance signal band, but their exact frequencies were chosen such that they are midway between two harmonics of the horizontal line repetition rate, thus ensuring that the majority of the power of the luminance signal does not overlap with the power of the chrominance signal.In the British PAL (D) system, the actual chrominance center frequency is 4.43361875 MHz, a direct multiple of the scan rate frequency. This frequency was chosen to minimize the chrominance beat interference pattern that would be visible in areas of high color saturation in the transmitted picture.The two signals (U and V) modulate both the amplitude and phase of the color carrier, so to demodulate them it is necessary to have a reference signal against which to compare it. For this reason, a short burst of reference signal known as the color burst is transmitted during the back porch (re-trace period) of each scan line. A reference oscillator in the receiver locks onto this signal (see phase-locked loop) to achieve a phase reference, and uses its amplitude to set an AGC system to achieve an amplitude reference.

The U and V signals are then demodulated by band-pass filtering to retrieve the color subcarrier, mixing it with the in-phase and quadrature signals from the reference oscillator, and low-pass filtering the results.

NTSC uses this process unmodified. Unfortunately, this often results in poor color reproduction due to phase errors in the received signal. The PAL D (delay) system corrects this by reversing the phase of the signal on each successive line, and the averaging the results over pairs of lines. This process is achieved by the use of a 1H (where H = horizontal scan frequency) duration delay line. (A typical circuit used with this device converts the low frequency color signal to ultrasonic sound and back again). Phase shift errors between successive lines are therefore cancelled out and the wanted signal amplitude is increased when the two in-phase (coincident) signals are re-combined.In the SECAM television system, U and V are transmitted on alternate lines, using simple frequency modulation of two different color subcarriers.

In analog color CRT displays, the brightness control signal (luminance) is fed to the cathode connections of the electron guns, and the color difference signals (chrominance signals) are fed to the control grids connections. This simple matrix mixing technique was replaced in later solid state designs of signal processing.

Synchronization:-Synchronizing pulses added to the video signal at the end of every scan line and video frame ensure that the sweep oscillators in the receiver remain locked in step with the transmitted signal, so that the image can be reconstructed on the receiver screen. A sync separator circuit detects the sync voltage levels and sorts the pulses into horizontal and vertical sync. (see section below – Other technical information, for extra detail.)Horizontal synchronizationThe horizontal synchronization pulse (horizontal sync HSYNC), separates the scan lines. The horizontal sync signal is a single short pulse which indicates the start of every line. The rest of thescan line follows, with the signal ranging from 0.3 V (black) to 1 V (white), until the next horizontal or vertical synchronization pulse.The format of the horizontal sync pulse varies. In the 525-line NTSC system it is a 4.85 µs-long pulse at 0 V. In the 625-line PAL system the pulse is 4.7 µs synchronization pulse at 0 V . This is lower than the amplitude of any video signal (blacker than black) so it can be detected by the level-sensitive "sync stripper" circuit of the receiver. Vertical synchronizationVertical synchronization (Also vertical sync or VSYNC) separates the video fields. In PAL and NTSC, the vertical sync pulse occurs within the vertical blanking interval. The vertical sync pulses are made by prolonging the length of HSYNC pulses through almost the entire length of the scan line.The vertical sync signal is a series of much longer pulses, indicating the start of a new field. The sync pulses occupy the whole of line interval of a number of lines at the beginning and end of a scan; no picture information is transmitted during vertical retrace. The pulse sequence is designed to allow horizontal sync to continue during vertical retrace; it also indicates whether each field represents even or odd lines in interlaced systems (depending on whether it begins at the start of a horizontal line, or mid-way through).The format of such a signal in 525-line NTSC is:

pre-equalizing pulses (6 to start scanning odd lines, 5 to start scanning even lines)

long-sync pulses (5 pulses) post-equalizing pulses (5 to start scanning odd lines, 4 to start

scanning even lines)Each pre- or post- equalizing pulse consists in half a scan line of black signal: 2 µs at 0 V, followed by 30 µs at 0.3 V.Each long sync pulse consists in an equalizing pulse with timings inverted: 30 µs at 0 V, followed by 2 µs at 0.3 V.In video production and computer graphics, changes to the image are often kept in step with the vertical synchronization pulse to avoid visible discontinuity of the image. Since the frame buffer of a computer graphics display imitates the dynamics of a cathode-ray display, if it is updated with a new image while the image is being transmitted to the display, the display shows a mishmash of both frames, producing a page tearing artifact partway down the image.Vertical synchronization eliminates this by timing frame buffer fills to coincide with the vertical blanking interval, thus ensuring that only whole frames are seen on-screen. Software such as video games and computer aided design (CAD) packages often allow vertical synchronization as an option, because it delays the image update until the vertical blanking interval. This produces a small penalty in latency, because the program has to wait until the video controller has finished transmitting the image to the display before continuing. Triple buffering reduces this latency significantly.Two timing intervals are defined – the front porch between the end of displayed video and the start of the sync pulse, and the back porch after the sync pulse and before displayed video. These and the sync pulse itself are called the horizontal blanking (or retrace) interval and represent the time that the electron beam in the CRT is returning to the start of the next display line.

Sync separator:-Image synchronization is achieved by transmitting negative-going pulses; in a composite video signal of 1 volt amplitude, these are approximately 0.3 V below the "black level". The horizontal sync signal is a single short pulse which indicates the start of every line. Two timing intervals are defined – the front porch between the end of displayed video and the start of the sync pulse, and the back porch after the sync pulse and before displayed video. These and the sync pulse itself are called the horizontal blanking (or retrace) interval and represent the time that the electron beam in the CRT is returning to the start of the next display line.

The vertical sync signal is a series of much longer pulses, indicating the start of a new field. The sync pulses occupy the whole of line interval of a number of lines at the beginning and end of a scan; no picture information is transmitted during vertical retrace. The pulse sequence is designed to allow horizontal sync to continue during vertical retrace; it also indicates whether each field represents even or odd lines in interlaced systems (depending on whether it begins at the start of a horizontal line, or mid-way through).In the television receiver, a sync separator circuit detects the sync voltage levels and sorts the pulses into horizontal and vertical sync.Loss of horizontal synchronization usually resulted in an unwatchable picture; loss of vertical synchronization would produce an image rolling up or down the screen.

TELEVISION STUDIO

A television studio is an installation in which video productions take place, either for the recording of live television to video tape, or for the acquisition of raw footage for post-production. The design of a studio is similar to, and derived from, movie studios, with a few amendments for the special requirements of television production. A professional television studio generally has several rooms, which are kept separate for noise and

practicality reasons. These rooms are connected via intercom, and personnel will be divided among these workplaces.

Studio floor:-

The studio floor is the actual stage on which the actions that will be recorded take place. A studio floor has the following characteristics and installations:

decoration and/or sets professional video camera (sometimes one, usually several) on

pedestals microphones stage lighting rigs and the associated controlling equipment. several video monitors for visual feedback from the production

control room (PCR) a small public address system for communication a glass window between PCR and studio floor for direct visual contact

is usually desired, but not always possibleWhile a production is in progress, people composing a television crew work the studio floor.

the on-screen "talent" themselves, and any guests - the subjects of the television show.

a floor manager, who has overall charge of the studio area stage management, and who relays timing and other information from the television director.

one or more camera operators who operate the professional video cameras, though in some instances these can also be operated from the PCR using remotely controlled robotic pan tilt zoom camera (PTZ) heads.

possibly a teleprompter operator, especially if this is a live television news broadcast

Production-control room:-

The studio control room (SCR) is the place in a television studio in which the composition of the outgoing program takes place. The production control room is occasionally also called a studio control room (SCR) or a "gallery" - the latter name comes from the original placement of the director on an ornately carved bridge spanning the BBC's first studio at Alexandra Palace which was once referred to as like a minstrels gallery.[1] Master

control is the technical hub of a broadcast operation common among most over-the-air television stations and television networks. Master control is distinct from a PCR in television studios where the activities such as switching from camera to camera are coordinated. A transmission control room (TCR) is usually smaller in size and is a scaled down version of central casting.Facilities in a PCR include:

A video monitor wall, with monitors for program, preview, VTRs, cameras, graphics and other video sources. In some facilities, the monitor wall is a series of racks containing physical television and computer monitors; in others, the monitor wall has been replaced with a virtual monitor wall (sometimes called a "glass cockpit"), one or more large video screens, each capable of displaying multiple sources in a simulation of a monitor wall.

A vision mixer, a large control panel used to select the multiple-camera setup and other various sources to be recorded or seen on air and, in many cases, in any video monitors on the set. The term 'vision mixer' is primarily used in Europe, while the term 'video switcher' is usually used in North America.

A professional audio mixing console and other audio equipment such as effects devices.

A character generator (CG), which creates the majority of the names and full digital on-screen graphics that are inserted into the program lower third portion of the television screen

Digital video effects, or DVE, for manipulation of video sources. In newer vision mixers, the DVE is integrated into the vision mixer; older models without built-in DVE's can often control external DVE devices, or an external DVE can be manually run by an operator.

A still store, or still frame, device for storage of graphics or other images. While the name suggests that the device is only capable of storing still images, newer still stores can store movingvideo clips and motion graphics.

The technical director's station, with waveform monitors, vectorscopes and the camera control units (CCU) or remote control panels for the CCUs.

In some facilities, VTRs may also be located in the PCR, but are also often found in the central apparatus room

Intercom and IFB equipment for communication with talent and television crew

A signal generator to genlock all of the video equipment to a common reference that requires colorburst

Master-control room:-

The Master control (MCR) room houses equipment that is too noisy or runs too hot for the Production control room (PCR). It also makes sure that coax cable and other wire lengths and installation requirements keep within manageable lengths, since most high-quality wiring runs only between devices in this room. This can include the actual circuitry and connections between

character generator (CG)

camera control units (CCU)

digital video effects (DVE)

video servers

vision mixer (Video Switcher)

VTRs patch panels

The Master control room in a US television station US, is the place where the on-air signal is controlled. It may include controls to playout television programs and television commercials, switch local or television network feeds, record satellite feeds and monitor the transmitter(s), or these items may be in an adjacent equipment rack room. The term "studio" usually refers to a place where a particular local program is originated. If the program is broadcast live, the signal goes from the PCR to MCR and then out to the transmitter.

COLOUR TEMPERATURE AND COLOUR BALANCE IN

PHOTOGRAPHY

Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, horticulture, and other fields. The color temperature of a light source is the temperature of an ideal black body radiator that radiates light of comparable hue to that of the light source. Color temperature is conventionally stated in the unit of absolute temperature, the kelvin, having the unit symbol K.Color temperatures over 5,000K are called cool colors (blueish white), while lower color temperatures (2,700–3,000 K) are called warm colors (yellowish white through red).[1] This relation, however, is a psychological one in contrast to the physical relation implied by Wien's displacement law, according to which the spectral peak is shifted towards shorter wavelengths (resulting in a more blueish white) for higher temperatures.

Temperature Source

1,700 K Match flame

1,850 K Candle flame, sunset/sunrise

2,700–3,300 K

Incandescent lamps

3,000 K Soft White compact fluorescent lamps

3,200 K Studio lamps, photofloods, etc.

3,350 K Studio "CP" light

4,100–4,150 K

Moonlight, xenon arc lamp

5,000 K Horizon daylight

5,000 Ktubular fluorescent lamps or Cool White/Daylight compact fluorescent lamps (CFL)

5,500–6,000 K

Vertical daylight, electronic flash

6,500 K Daylight, overcast

6,500–9,300 K

LCD or CRT screen

These temperatures are merely characteristic;

Colour Balance:-

If you want to accurately simulate the way a light source would appear if it were really photographed, then you need to start by understanding the idea of colour balance.Colors of light do not directly translate into the tints that are reproduced in a photograph. Instead, the colors that appear in a photograph are relative to the color balance of the film that was used.The color balance of the film determines what color of light will appear to be white light.Color balancing is not unique to film. A similar adjustment, called white balance, is accomplished electronically on video cameras and digital cameras.Even your own vision automatically adjusts to compensate for different colors of light. For example, imagine that you were wearing a white shirt at night in front of a campfire, where everything was lit by red firelight. Once you have grown accustomed to the light, you would perceive the shirt as being white, even though you see red when you look at the shirt in the red light of a fire. In much the same way that the automatic white balance of a digital camera adjusts the signal to respond to colored light, your brain compensates for different colors of light and manages to perceive a white shirt where it sees red.Most 3D rendering programs do not have controls to simulate different color balance. Instead, you need to mentally take color balance into account in adjusting the color of your lights. This means that you must know two things before you can pick a realistic light color: the characteristic color of the type of light source you want to represent, and the color balance you want to simulate in your rendering.The color of a light and the color balance of photographic film are both described by a color temperature, which is measured in degrees Kelvin. This is the standard system used by filmmakers and photographers to discuss colors of light. It is worth taking a few minutes to understand color temperatures and photographic color balancing, in order to pick more realistic colors for the lights in your 3D scenes.

SATELLITE COMMUNICATION

A communications satellite (or COMSAT) is an artificial satellite stationed in space for the purpose of telecommunications. Modern communications

satellites use a variety of orbits including geostationary orbits, Molniya orbits, other elliptical orbits and low (polar and non-polar) Earth orbits.For fixed (point-to-point) services, communications satellites provide a microwave radio relay technology complementary to that of communication cables. They are also used for mobile applications such as communications to ships, vehicles, planes and hand-held terminals, and for TV and radio broadcasting, for which application of other technologies, such as cable television, is impractical or impossible.

EARTH STATION:-

A ground station, earth station, or earth terminal is aterrestrial terminal station designed for extraplanetary telecommunication with spacecraft, or reception of radio waves from an astronomical radio source. Ground stations are located either on the surface of the Earth, or within the atmosphere. Earth stations communicate with spacecraft by transmitting and receiving radio waves in the super high frequency or extremely high frequency bands (e.g., microwaves). When a ground station successfully transmits radio waves to a spacecraft (or vice versa), it establishes a telecommunications link.Ground stations may occupy either a fixed or itinerant position. Article 1 § III of the ITU Radio Regulations describes various types of stationary and mobile ground stations, and their interrelationships. Specialized satellite earth stations are used to telecommunicate with satellites—chiefly communications satellites. Other ground stations communicate with manned space stations or unmanned space probes. A ground station that primarily receives telemetry data, or that follows a satellite not in geostationary orbit, is called a tracking station.When a satellite is within a ground station's line of sight, the station is said to have a view of the satellite. It is possible for a satellite to communicate with more than one ground station at a time. A pair of ground stations are said to have a satellite in mutual view when the stations share simultaneous, unobstructed, line-of-sight contact with the satellite.

UPLINK:-

Pertaining to satellite communications, an uplink (UL or U/L) is the portion of a communications link used for the transmission of signals from an Earth terminal to a satellite or to an airborne platform. An uplink is the inverse of a downlink. An uplink or downlink is distinguished from reverse link or forward link.

Pertaining to GSM and cellular networks, the radio uplink is the transmission path from the mobile station (cell phone) to a base station (cell site). Traffic and signalling flows within the BSSand NSS may also be identified as uplink and downlink.

Pertaining to computer networks, an uplink is a connection from data communications equipment toward the network core. This is also known as an upstream connection.

DOWNLINK:-

In the context of satellite communications, a downlink (DL) is the link from a satellite to a ground station.Pertaining to cellular networks, the radio downlink is the transmission path from a cell site to the cell phone. Traffic and signalling flows within the base station subsystem (BSS)

and network switching subsystem (NSS) may also be identified as uplink and downlink.Pertaining to a computer networks, a downlink is a connection from data communications equipment towards data terminal equipment. This is also known as a downstream connection.

TRANSMITTER:-

In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves. In addition to their use in broadcasting, transmitters are necessary component parts of many electronic devices that communicate by radio, such as cell phones, wireless computer networks, Bluetooth enabled devices, garage door openers, two-way radios in aircraft, ships, and spacecraft, radar sets, and navigational beacons. The term transmitter is usually limited to equipment that generates radio waves for communication purposes; or radiolocation, such as radar and navigational transmitters. Generators of radio waves for heating or industrial purposes, such as microwave ovens or diathermy equipment, are not usually called transmitters even though they often have similar circuits.The term is popularly used more specifically to refer to a broadcast transmitter, a transmitter used in broadcasting, as in FM radio transmitter ortelevision transmitter. This usage usually includes both the transmitter proper, the antenna, and often the building it is housed in.An unrelated use of the term is in industrial process control, where a "transmitter" is a telemetry device which converts measurements from a sensor into a signal, and sends it, usually via wires, to be received by some display or control device located a distance away.

Block diagram of a TV transmitter (intercarrier method).

HDTV

High-definition television (HDTV) provides a resolution that is substantially higher than that of standard-definition television.HDTV may be transmitted in various formats:

1080p - 1920×1080p: 2,073,600 pixels (approximately 2.1 megapixels) per frame

1080i - typically either: 1920×1080i: 1,036,800 pixels (approximately 1 megapixel)

per field or 2,073,600 pixels (approximately 2.1 megapixels) per frame

1440×1080i:[1] 777,600 pixels (approximately 0.8 megapixels) per field or 1,555,200 pixels (approximately 1.6 megapixels) per frame

720p - 1280×720p: 921,600 pixels (approximately 0.9 megapixels) per frame

The letter "p" here stands for progressive scan while "i" indicates interlaced.When transmitted at two megapixels per frame, HDTV provides about five times as many pixels as SD (standard-definition television).