99094832 Doordarshan Report

Doordarshan Kendra,Guwahati

ACKNOWLEDGEMENT

It has been a proud privilege for me to complete my in-plant training with Doordarshan Kendra guwahati.

I express my sincere thanks and gratitude to all the people who have help me and supported me throughout my study. I would like to thank MR DIPAK KUMAR SHARMA, asst engineer, DDK, Guwahati for his continuos guidance and extreme support at every of training period 21-06-2012 to 04-07-2012.

I would also like to offer my special thanks to all the staff members who spent their precious time to take our classes.

At last I would like to thank our placement officer for us the opportunity to apply for the training.

Department Of Electronics & Communication Engineering


AIM OF THE TRAINING

The main aim of the training was to get a firsthand experience of the Television Broad casting System and to be familiar with all the functional and technical aspects associated with it.

SCOPE

At DDK we were provided with all the scopes required for training. It was well equipped with modern technology studio, various indoor and outdoor cameras, Camera Control Unit (CCU), Master Switching Room (MSR), Earth Station, Parabolic Dish Antenna (PDA), Digital Satellite News Gathering (DSNG), and Outdoor Broadcasting Van (OB vans).



INTRODUCTION

History of Doordarshan Kendra, Guwahati can be recalled from 1982 when the country hosted the 9th Asian Games at New Delhi. The journey began on 19th November in the same year with the 100 Watt (VHF) Low Power Transmitter (in short LPT) installed at ALL INDIA RADIO complex, Chandmari to radiate the Doordarshan National Programme (DD-1). Later, the LPT was upgraded to 10 KW (VHF) High Power Transmitter (HPT) and installed atop Narakasur Hill. The HPT started functioning since 21st January 1985. Same year, an interim studio was set up at Mahendra Mohan Chowdhury (MMC) Hospital Complex at Panbazar with 3 numbers of black and white (B/W) camera in studio and 2 numbers of ENG (Electronic News Gathering) units equipped with M-3 camera.

Outdoor Broadcasting Van (OB Van) was introduced in the Kendra in 1987 to felicitate live coverage of different events outside.

A 10 Watt (VHF) Transmitter (also called Transposer) was installed in 1989 at Nabagraha Hill to cater the needs of shadow area population of Kharghuli hill side area of the city.

In 1992, the makeshift studio setup at Panbazar was shifted to its permanent office complex at R.G. Baruah Road and started functioning since 7th February. Presently, the Kendra is equipped with two nos. of studios with complete digital upgraded set up for facilitation of recording and transmission of regional program of Assam.

In 1994, 300W (UHF) LPT was installed at Transmitter complex, Narakasur Hill and started radiating DD#2 (Metro Service) program since 27th November.

At present Doordarshan Kendra, Guwahati with its full-fledged latest technology and broadcast set up, has earned the reputation of being one of the Major Kendras of the country. Further to add to its glory, the Kendra has won the "Best Maintained Kendra" in Northeast for the year 2009-10.



MAIN STUDIO

The main studio is fully digitized with four cemera setup. It is having different types of microphone and equipped with different lights including cool lights used as per production requirements. This studio is mainly used for all major recordings and live interactive program using phone in console. This studio has dimension of 22mtr. X 16.5mtr active program using phone in console.

Characteristics of main studio:i. It is the place where the main production part is done.ii. There should not be any type of eco, i.e the walls of the room should be ecostatically treatmented.iii. Light should be properly reflected, so that the picture quality is good.

iv. Cyclorama- A big screen is used for video treatement.

The main components of Main studio:i. Lightii. Camera

iii. Sound



Light:It is a form of radient energy which propagates in the form of

electromagnetic waves. A bunch of electrons. Temperature of light vary with respect to frequency. Depending on temperature colour of light changes.

Different types of light:i. Spot light: Used for to directly illuminate a particular space. Focusing,

zooming and intensity adjustment is also done here.a. Key light : Less intensaity lightb. Hard light: More intensity light

ii. Field light: To reduce the shadow of the object.iii. Back light: To separate the object from the shadow.iv. CFL: For power saving purpose.v. Neon light

The spot light is having some disadvantages of consuming more power that’s why we use CFL lights.

Camera:When light falls on an object an optical image is formed, which is captured by

the camera and is converted into electrical energy.

Main parts of camera:i. Lensii. Pickup deviceiii. Electronics

In lens part zoom in ,zoom out a and focusing is done. CCD in pickup device is used for transforming the light energy into charge energy by scanning method.



CB STUDIO

This studio has a dimension of 9.2mtr. X 6mtr. This studio is fully digitalized with 2 camera setup. This studio is mainly used for live transmission of NEWS. Some discussion type as well as anchorig program is also generated by this studio.

In the studio 2 Thomson cameras, 1 Teleprompter camera and 2 Microphones are used. The Teleprompter camera is used to reflect the NEWS lines from the paper to the

screen present infront of the NEWS reader.

ENG SECTION

The NEWS and EFP(Electronics field production) is covered by ENG section. This section is equipped with 19 numbers of DVC PRO Camcoders and 3 numbers of Mini DV Camcoders, different types of microphones, lights used as per the production in the field.

DVC PRO means Digital Video Cassete portable camera. It is a portable and having light weight, so it is easy to carry and is operated with battery (types: trimpac(45WH),dianic(65WH),propac(65WH),14.4 volt each). The main advantage of DVC PRO camera is that it can do audio, video and recording all together.

Video:DVC PRO camera lens is having 4 parts:

i. Focusii. Zoom in-zoom out.

iii. Irisiv. Back focus

Iris controls the intensity of the light. Back focus adjust the backgroung, specially the colours.



We also use filters for different weather conditions:There are 4 types of filters

A. 3200K B. 5600K+1/8NDC. 5600KD. 5600K+1/64ND, where ND means neutral density.

Audio:In DVC PRO camera, there are 3 mikes for audio

i. Front ii. Wireless

iii. RearAudio level should not be 0dbBassically there are 3 types of mikes: i. uni-directional (used in TV). ii. bi-directional (used in Radio).

iii. omni-directional (used in songs).There are also another 2 mikes Lapel mike (small mike used in shirt) and Lip mike (used in commentary board).

Recordings:

For recording we use VTR(video Tap Recording). We use cassettes for

recording. The VTR is the next section where copies of all programs are stored. All the

programs shot in the camera are simultaneously recorded in the VTR. Also plays back

all the as and when required. Videos and pre-recorded events are queued up in the VTR

and are played back without a break i.e, played synchronously. Videos of famous

peoples and importantevents are stored in the central film pool.



EDITING

Editing means to prepare a programme for publication or for

broadcasting etc especially by correcting , altering , shortening etc.

Basicaaly there are two types of editing:

i. Linear Editing.

ii. Non Linear Editing

In early days Linear editing was the only way to edit video tapes. Then, in

1990s, non-linear came into being and available. In 21st century non-linear

editing is considered to be obsolete, or at least primitive.

Linear Editing :

Advantages:

i. It is simple and inexpensive. There are very few complications with

formats, hardware conflicts, etc.

ii. For some jobs linear editing is better . For example, if all you want to

add two sections of video together, it is a lot quicker and easier to edit

tape-to-tape than to capture and edit on ahard drve.

iii. Linear editing is the base of learning editing.



Block Diagram for Linear Editing:

Fig.1: Block Diagram of LE

Non- Linear Editing:

A non-linear editing system(NLE) is a video – (NLVE) or audio editing

(NLAE) digital audio workstation (DAW) system wich can perform non-

desructive editing on the source material.

i. Metadata - When ingesting audio or video feeds , metadata are

attached to the clip . Those metadata can be attached automatically

(time, localization, name of the clip etc) or manually ( players names,

characters etc).

ii. Direct Access - With historical video tape linear editing systems. It is

now possible to access any frame by entering directly the time code

or the descriptive metadata.


MONITOR

EDIT CONTROL

VTR VTR


Advantage of NLE:

i. In NLE, the original source files are not lost or modified during editing.

ii. In NLE the decision of the is recorded in an edit decision list (EDL)

which can be interchanged with other editing tools.

Block diagram for NLE:

Fig.2: Block Diagram of NLE

Main differences between Linear and Non- Linear editing:

Non-linear editing is the most natural approach when all assets are

available as files on hard disks rather than recordings on reels or tapes, while

linear editing is related to the need to sequentially view a film or read a tape to

edit it.


Source Digital s/g Store in Galaxy

Placed in Binary

Down the editing material

Making movie Editing in time line

Drag to time line


MASTER SWITCHING ROOM

The embedded SDI video signal from the studios is monitored in MSR and

send to Earth station through Optical fibre cable(OFC). The in-coming News-feed

through satellite from all the state capitals of the northeast are received through an array

of IRDs and recorded. In addition to this, News-feeds are received through ISDN from

same Kendras which do not have uplink facility and through internet also. The News-

feeds so received are used for Assamese News (Batori) and North East English News

Bulletin originating from DDK, Guwahati.

The MSR is the main hot switching room of Doordarshan Kendra for receiving and

transmitting of various audio / video signals from different places.

Its infrastructure provides facility for routing any signal from any input to required

systems for recording and transmission.

In order to ensure smooth reception of multiple sources for studio

production,transmission of programs / News from studio to Earth station and

transmitter and proper monitoring of the audio & video quality latest equipmemnts

have been installed in the MSR.



VIDEO TAPE RECORDING

Video tape recorders records video clips in the form of analog or digital format on a magnetic tapes. The tape acts as a storage device to store a TV program up to 90 minutes duration on a video cassette. A VTR includes analog and digital processing of audio/ video signal, servo system, microprocessors, memories etc.

SI No. Item Audio Recorders Video Recorders 1. Frequencis

involved20 Hz to 20 KHz 20 Hz to 5 MHz

2. No. of octaves 10 183. Recording

mediumNot so important Very important

4. Recording medium limitation

No Yes*

Magnetic Principle:Faraday’s law of magnetism provided the rules for conversion of electrical signals to magnetic form. Certain materials when brought in a magnetic field get magnetized and retain the magnetism permanently until altered. High value of permeability (µ) of this material helps to enhance this conversion.Magnetic field intensity H=NI/L(for a coil with N turn and L as length)Magnetic flux density B=µHMagnetic Flux Ø=BA

Property of the ferromagnetic materials to retain magnetism even after the current (or the H) is removed is called retentivity and is used for recording electrical signals in magnetic form on a magnetic tape.



EARTH STATION

Earth station is a uplink centre from which the signals are fed to Satellite for

contribution in a specified area covered by satellite. The signal is up-linked

from the station and received by one down-link centre at studio/production

centre. Both analog and digital signals are used for uplink. But digital signal is

more useful.

Problems of analog signals:

1. One programme per channel/transponder

2. Comparatively noisy

3. Ghosts in terrestrial transmission

4. Lower quality with respect to VCD, DVD digital media

5. Fixed reception

Advantage of Digital signals-

1. More programmes per channel/ transponder i.e. spectrum efficient

2. Noise- Free reception

3. CD quality sound and better than DVD quality picture

4. Reduced transmission power

5. Flexibility in service planning- quality/ Bandwidth trade off more

services per transponder

6. Lower uplink power per carrier , leads to lower load of HPA, Genset.

UPS etc.

7. Automated operation in broadcast plan

8. Non availability of analog systems in near future

9. Future of TV transmission- DTH, DTT and Digital Cable



Block Diagram of Earth Station:

Fig.3: Block Diagram of Earth Station

1. From the MSR which is more than 200 metres away from earth station,

the signal is transmitted through optical fibre cable (OFC).

2. In OFC audio and video is embedded and received in baseband section

of earth station.

3. From baseband section it is sent to compressor rack.

4. The compressor rack consists of two encoders where signals are

converted to machine language.

5. Then both the signals are given to MUX where it is converted to a sinsle

signal.

6. Then it is given to the modulator (QPSK) which uses a carrier signal of

70Mhz.

7. But for uplink to satellite it requires 6Mhz.

8. So the signal is sent to a up convertor which consists of a mixture that

adds Local Oscillator frequency to the main frequency.

9. The local oscillator frequency is 6065.5Mhz.


MSR Baseband section

Compressor rack

Modulator

Up Convertor High Power Amplifier(HPA)

Outdoor unit(Satellite- PDA)


10.Then the signal is given to the HPA for amplification.

11.From HPA it is given to the feed of the Parabollic dish antenna (PDA).

12.The PDA consists of 4-port feed.

13.Two for transmission ( one for horizontal and another for vertical) and

two for reception ( one for horizontal and another for vertical).



OUTDOOR BROADCASTING VAN

The Kendra has an OB Van equipped with 8 camera full digital setup. For live

coverage, it is used along with KU Band DSNG Van. Additionally one KU Ban Fly

Away DSNG is also provided. The power to outdoor setup is fed through a 33 KVA

portable DG set. 3 X 6 KVA UPS system is provided for uninterrupted power supply.

Fig.4: Outdoor Broadcasting VAN

DSNG SYSTEMSIn addition to digital video broadcast systems, CommSystems provides

digital satellite newsgathering technology and systems. Transportable trailers, vans and flyaway packages utilizing MPEG-2 digital compression, and single or multiple hub sites are a few of the elements that CommSystems can engineer into your DSNG network solution. CommSystems has provided Ku-band, C-band, and dual band systems as well as a mixture of digital video, analog video, and combinational systems.



Components of DSNG:

1. PDA(Parabolic Dish Antenna)2. FEED3. LNA / LNBC4. Wave Guide / Low Loss Cable5. HPA(TWTA,SSPA,Klystron)6. Up-converter7. Modulator8. Encoder9. Multiplexer10.IRD(Integrated Receiver Decoder)


99094832 Doordarshan Report

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