Television System and Broadcasting

Doordarshan Kendra DelhiSummer Training

PresentationPankaj BishtB.Tech ECEV semester

Broadcasting Distribution of audio and/or video content to a

dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum (radio waves), in a "one to many" model.

The field of broadcasting includes a wide range of practices, from relatively private exchanges such as amateur (ham) radio and amateur television (ATV) and closed-circuit TV, to more general uses such as public radio, community radio and commercial radio, public television, and commercial television.

Broadcasting in India Terrestrial Earthbound broadcast from antenna towers here on Earth Terrestrial TV also makes use of satellites, but rather than broadcasting directly to a customers dish, they are broadcasting specifically for re-broadcast by local network affiliates over their terrestrial antennas.

Satellite Broadcast by communications satellites from outer space in geosynchronous orbit.

Internet A webcast is a media presentation distributed over the Internet using streaming media technology to distribute a single content source to many simultaneous listeners/viewers. A webcast may either be distributed live or on demand. 

TV Studio Video productions take place, either for the recording of live television to video tape, acquisition of raw footage for post-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.

Parts of T.V studio Action areaIt is the areas were the artist performs the action i.e. the program which is to broadcasted.

The main parts of action area are as follows:- Camera head unit Floor preparation Audio connecter boxes Lightning stand and color Light Microphones Video monitors for visual feedback from the production control room talkback systemfor communication

Production Control Room (PCR)

The P.C.R includes- A video monitor which monitors the PROGRAM,

VTRs, CAMERAS, GRAPHICS and other video sources. Video monitors consists of series of television sets or computer monitors which is capable of displaying multiple sources.

A vision mixer, a large control panel used to select the video sources to be seen on air and in many cases in any monitors on the set.

Digital video effects, or DVE, for manipulation of video sources.

The technical director watches the waveform of the video signals and directs the cameraman accordingly for the high quality video signals.

Master Control Room (MCR)

Master control is the technical hub of a

broadcast operation.

MCR is the final point before a signal is

transmitted for broadcast.

MCR include banks of video monitors, satellite receivers, videotape machines, video servers, transmission equipment, and,computer broadcast automation equipmentfor recording and playback of television programming.

It checks the actual circuitry and connection boxes of vision mixer, DVE and character generator.

It also controls on-air signal. It may include controls to play back programs, switch local or network feeds, satellite feeds and monitors the transmitter.

Character GeneratorsIt creates the majority of names and graphics that is to be inserted into programs.

Control Appartus RoomIt includes the power control room, UPS room and generator for uninterrupted power supply.

Video Tape RecorderRecord video material, usually on a magnetic tape.

Other facilitiesOne or more make-up and changing roomsA reception area for crew, talent, and visitors, commonly called the green room.

Earth Station

The earth-based communications station providing the communication link to a communications satellite. The earth station itself is usually an antenna that includes a low-noise amplifier, a down-converter, as well as an electronics receiver. The antenna itself can vary in size from at little at 3 to 30 meters, depending on its usage.

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 

Downlink(DL) is the link from a satellite to a ground station.

Television Transmitter Electronic device which, with the aid of an antenna, produces radio waves.

The transmitter itself generates a radio frequency alternating current, which is applied tothe antenna. When excited by this alternating current, the antenna radiates radio waves.

10KW Transmitter for DD-NEWS 10KW Transmitter for DD-NATIONAL

TV TRANSMITTER TYPES

(A) VERY LOW POWER TX (VLPT) TV TRANSMITTERS HAVING OUTPUT POWER 10 W , 50 W.

(B) LOW POWER Tx (LPT) TV TRANSMITTERS HAVING OUTPUT POWER LESSTHAN 1KW AND MORE THAN 50W .( 100W , 300W , 500W )

(C) HIGH POWER Tx (HPT) TV TRANSMITTERS HAVING OUTPUT POWER 1KW AND ABOVE .( 01KW , 10KW , 20KW, 30KW )

Satellite Broadcasting

Delivering television programmes by the means of communications satellites. The signals are received by an outdoor antenna, generally referred to

as a satellite dish, and as far as household usage is concerned, a satellite receiver is either in the form of an external set-top box or a satellite tuner module built into a television set.

Satellite television tuners are also available as a card or a USB peripheral to be attached to a personal computer.

Earth Station At DDK Delhi Doordarshan Kendra Delhi has (8+1)-SD and (1+1)-HD uplink Digital

Earth station. This earth station uplink the programmes at C-band to INSAT- 4B satellite on MCPC scheme.

The Satellite 4-B was launched in March 2007 by the European Ariane launch vehicle. Configured with payloads identical to that of INSAT-4A, INSAT-4B carries 12 Ku-band and 12 C-band transponders to provide equivalent isotropically radiated power ( EIRP) of 52 dBW and 39 dBW respectively. It is co-located with INSAT-3A at 93.5 degree E-longitude.

The Digital earth station’s C-Band Uplink Frequency is 5.85 to 6.425 GHz and Downlink Frequency is 3.4 to 4.2 GHz. The uplink channels on (8+1)-SD are DD-National , DD-Urdu, DD-Bharati, DD-India, DD-Sports, DD-Rajya Sabha, DD-Feed, and DD-News. The Digital earth station is also uplinking the HD programme on (1+1) i.e.DD-HD.

 TELEVISION STANDARDS

NTSC - National Television Standards CommitteeDeveloped 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.

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.

PAL - Phase Alternating LineDeveloped in Germany and first used in 1967. A variant of NTSC, PAL uses a 625/50-line display.

PAL standard utilizes a wider channel bandwidth than NTSC which allows for better picture quality.  TELEVISION STANDARD USED IN INDIA IS PAL.

Summary of the Analog TV Standards

fps lines Band-width (MHz)

B&W Mod.

Colour Mod.

Audio Mod.

NTSC 30 525 6 AM QAM FM

PAL 25 625 7-8 AM QAM FM

SECAM 25 625 7-8 AM FM FM

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DTH- Direct to Home Transmission There are five major components involved in a direct to home (DTH) satellite system: the programming source, the broadcast center, thesatellite, the satellite dish and the receiver.

The satellites receive the signals from the broadcast station and rebroadcast them to the ground.

The viewer’s dish picks up the signal from the satellite (or multiple satellites in the same part of the sky) and passes it on to the receiver in the viewer’s house.

The receiver processes the signal and Satellite & Cable TV passes it on to a standard television.

The broadcast center converts all programming into a high-quality, uncompressed digital stream. At this point, the stream contains a vast quantity of data — about 270 megabits per second (Mbps) for each channel.

In order to transmit the signal from there, the broadcast center has to compress it. Otherwise, it would be too big for the satellite to handle.

The providers use the MPEG-2 compressed video format — the same format used to store movies on DVDs. With MPEG-2 compression, the provider can reduce the 270-Mbps stream to about 3 or 10 Mbps (depending on the type of programming).

With digital compression, a typical satellite can transmit about 200

channels. Without digital compression, it can transmit about 30 channels.

Broadcast center

ENCRYPTION & TRANSMISION

After the video is compressed, the provider needs to encrypt it in order to keep people from accessing it for free.

Encryption scrambles the digital data in such a way that it can only be decrypted (converted back into usable data) if the receiver has the correct decoding satellite receiver with decryption algorithm and security keys.

Once the signal is compressed and encrypted, the broadcast center beams it directly to one of its satellites.

The satellite picks up the signal, amplifies it and beams it back to Earth, where viewers can pick it up.

Digitization in DD and AIR broadcasting

DRM - Digital Radio Mondiale

Set of digital audio broadcasting technologies designed to work over the bands currently used for AM broadcasting, particularly shortwave.

DRM can fit more channels than AM, at higher quality, into a given amount of bandwidth.

DRM can deliver FM-comparable sound quality on frequencies below 30 MHz (long wave, medium wave and short wave), which allow for very-long-distance signal propagation.

DRM incorporates technology known as Emergency Warning Features that can override other programming and activates radios on standby in order to receive emergency broadcasts.

DRM and DTT

Why DRM? Limitations of AM radio Broadcasting. Low audio quality due to audio bandwidth limitations. Susceptibility to atmospheric and electrical interference AM radio signals can be severely disrupted in large urban centres by

metal structures, tall buildings and sources of radio frequency interference (RFI) and electrical noise, such as electrical motors, fluorescent lights, or lightning.

DRM allow the new digital transmissions to co-exist with the current analogue broadcasts.

In the VHF bands, DRM+ can be configured to use less spectrum than current stereo FM broadcasts.

DRM provides support for Broadcasting in all frequency bands currently used for AM and FM analogue radio.

Up to four services per frequency, each of which can be any mixture of audio and data

DTT- Digital Terrestrial Transmission Digital Television is the way of future, providing interference free

reception and remarkable picture & sound quality.

Features Spectrum Efficiency Multi-channel Capability Immunity to Disturbance Portable & Mobile TV Enhanced services (such as Electronic Programme

Guide) Lower Power Operation

Thankyou