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CONTENTS

• Acknowledgement

• About Doordarshan Kendra Hisar

• Studio

• Equipment Room

• Video Basics

• Production Control Room

• Editing Room

• Earth Station

• High Power Transmitter

• PDA-Parabolic Dish Antenna

Acknowledgement



Words fail to express ones feeling towards other still we express our sincere

gratitude to Sh. D.P. Singh, Assistant Engineer DOORDARSHAN

KENDRA, HISAR for their valuable guidance without which it would have

been difficult for us to achieve our aim.

we also express our gratitude to Sh. Sandeep Kaushik , Sh. S.N. Gera,

Sh. B.S.Bisth, Prithvi Singh Dahiya ,Sh. N. K. Gijwani , Sh. Chander

SEN who helped a lot in studying the various instruments.

It was really a good experience working in the institute and learning from such

good and knowledgeable people. We hope it would be really helped to us in the

near future.

ISHANTSANCHIT SINDHWANI

ANIL SHARMA

MAHARISHI MARKENDESHWAR ENGINEERING COLLEGE, MULLANA

DOORDARSHAN KENDRA,

HISAR



Doordarshan Kendra, Hisar, was established on 1st November 2002,

on the auspicious Haryana day. The center was inaugurated by the

honorable Mrs. Sushma Swaraj, the Information and Broadcasting

minister. It is stretched over 4 acres of land. This fully air

conditioned centre is one of the highly advanced & well equipped Doordarshan Kendra in India. This center is completely available

with Digital equipment facilities. There are highly sophisticated

digital equipments which are handled by the well trained & skilled

engineers. Haryana’s, only ‘Earth station’ lies in this center, for

the transmission of programs in whole of Haryana. From 5.00 pm

to 7.30 pm every LPT of Haryana state has to tune to the

frequency of Hisar and has to telecast programs from Hisar. The

HPT of Doordarshan Hisar consists of UHF CH=31 frequency 551.25

MHz (for DD1) and UHF CH=33 frequency 567.25MHz (for DDNEWS)

transmitters for receiving the feeds from Delhi and for

transmission of DD1 & DDNEWS in the local area (Hisar). From 5.00

pm to 7.30 pm no feed from Delhi is transmitted in the state but

the programs of DD-Hisar are transmitted at UHF in the local area

through the MAST tower and in the whole Haryana region through

the Earth station.

The basic aim of the Doordarshan Kendra, Hisar is to promote

Haryanvi culture & to enhance the development process in the

agro land. And this center, no doubt, is spreading education &awareness in the different parts of Haryana (especially the rural

areas) through its programs. It is a land mark in the history of

Haryana.

The further tasks & the features of the center are described in the

subsequent sections.



BASIC TASK PERFORMED

PDA



HIGH POWER TRANSMITTER

AUDIO-VIDEO

SWITCHER

RECEIVER

DEMODULATIO

N

AUDIO-VIDEO

SWITCHER

RECEIVING RACK

POWER

AMPLIFIER

EXCITER

IF

MODULAT

OR

TRANSMITTING RACK



STUDIO

TV STUDIO HALL

Doordarshan have their own shooting studio. Studio Hall is used to

shoot various programs. Artificial set is created in the studio hallaccording to requirements of the program to be shot. Studio hall

contains no’s of lights to give natural effect to artificial set.

Studio hall contains many devices for shooting and for creating

natural set also. Like …..

Lighting winches and control board

Cyclorama

Many microphone connections Makeup room

Furniture

Cameras

Sound absorbers

Doordarshan produces their own programs like ”GHAR

ANGAN”,”HARYANVI RAGNI” and also live programs like ”KISAN”

and “DD NEWS” in this studio.



Lights are hanged over the lighting winches and arranged in row.

Types and purpose for lighting will be explained under the title

“Studio Lighting”.

Cyclorama is nothing but a special type of white curtain hanged

with the wall in three dimensions. Cyclorama works as the light

and color absorbers to maintain original color tone on video

output. Because of its white color it is also used to create

background of various colors by using color paper on lightings

Many microphone connections hanged in between the winches are

used to attach the microphones during dialog delivery in play.

White colored walls act as a sound absorber material to reduce

the echoes.

Whole studio is centrally air conditioned and all the doors kept

airtight for preventing outer voice coming into studio.

Studio is also known as main action area. This place requires very

large place compared to other sections. Action in this area includes

staging, lighting, performance and arrangement to pickup picture

and sound.

Requirements of TV Studio:-

Very efficient air conditioning

Uniform and smooth floor for smooth movement of cameras

Efficient sound absorbers

Effective communication with other sections

3 to 4 studio cameras with teleprompter

Cyclorama and curtain

Audio and video monitors

Warning light and safety devices like fire alarm, firefightingequipment

Digital clock display



STUDIO LIGHTING

The master key is used for creating 3-D and natural effect in studio.

Doordarshan uses 125 direct lights and 48 dimmers hanged on

winches in main recording studio.

Why lighting is done?

When we shoot outdoor program, the source of light is sun. The

natural effect we see in outdoor is greatly depends on the proper

lighting.

There are two main reasons to use light techniques in studio. First

is when we prepare artificial set to look like natural, we have to

give the proper lighting effect as if it was outdoor. Lighting also

depends on the mood of the scene. Secondly, the output picture of

the camera is 2D, while natural scenes we see are 3D, therefore on

T.V. screen to differentiate the main object from the background3D effect lighting is must.

Types of lights:-In Doordarshan halogen and cool day lights are

used.

Lighting techniques

To understand lighting techniques we should know all the

parameter of lights, those are…..

Quantity Quality

Color temperature

Contrast ratioQuantity means the amount of light or amount of radiated energy

by the source of light and quality means the type of light source

used.

Contrast ratio is the difference between highly lighted and darkestpart of the scene.



Different lights and colors have their own temperature known as

color temperature. When a black body is heated, it may be noted

that color of body changes from black to red and then toward

white as temperature increases. Different sources have their own

Color temperature; some no’s of color temperature for different

light sources are listed below:

• Sun light 5600 Kelvin

• Studio lamp 3200 Kelvin

• Domestic lamp 2780 Kelvin

• Fire 1930 Kelvin

• Cloudy day 6500 Kelvin

• Clear blue sky 12000 Kelvin

Nature has provided us two types of light hard and soft.

Hard light is a point source light so the shadow of the object looks

sharper. In nature sun is the hard light source and other reflecting

clouds, hills and buildings are soft sources. The shadow of the

object under soft light source looks feathered and soft.

In studio mainly “THREE POINT LIGHTING” technique is used. Thesethree points are…

1. Key light2. Fill light3. Back light

KEY LIGHT:- is the main light used to highlight any object or to give

attention toward the person. This is full intensity light used to

highlight the depth of object or human face. Key light is usually a

hard source at an angle of 15-30 degree to camera axis at an

elevation of about 40 degree.

FILL LIGHT:-is the 80% intensity of key light and at the opposite side

of the camera axis. Fill light is used to suppress the shadow made

by key light. It is soft light and used to fill the light in whole room.

BACK LIGHT: - is used to separate artist from the background and so

to produce 3D visualization. It is hard source located at 180 degree

of camera axis.The three point lighting ratio 3:2:1(back: key: fill) in

monochrome and 3:2:2 in color provide good portrait lighting.



The last is the background light used to highlight the background

of the scene or to create color background on white cyclorama.

BALANCE OF LIGHT:-

• Key light 100%• Fill light 85%• Back light 110%• Background light 50-60%

The motors attached with winches by metal belts control the height of

the lights. Movement of winches is controlled from the control panel

which also contains the connection for talkback system. Intensity

and power on/off of lights are controlled from the LCU(light control

unit).

EQUIPMENT ROOM

Firstly, the video signal from the camera comes into the base

station placed in equipment room and synchronous pulses



generated in equipment room are also given to base station. From

base station video signal goes to CCU (camera control unit) placed

in PCR and base station also gives 3 outputs that are SDI signal,

COMPONENT signal and COMPOSITE signal. Out of these three SDI

signal is given to the switcher and COMPOSITE signal is given tothe monitor placed in PCR (production control room) for monitoring

purpose.

Equipment Room consists of 4 racks.

RACK 1:-

1. Sync. Pulse generator : - It is used to generate the sync. Pulsesand these pulses are provided to all devices using sync. Pulsecontroller.

2. Analog Patch Panel: - These patches are provided to directly bypass the output. It contains source above and destination

below.3. Base Station : - 3 base stations are provided for 3 cameras.

Each base station give 3 video signals that is SDI signal,COMPOSITE signal and COMPONENT signal.

4. AVDA : - Analog video distribution amplifier is used to divideone input into many outputs.

RACK 2:-

1. DIGITAL PATCH PANEL : - It contains patches for digital data and

it is used to directly by pass the video signal. It containssource and destination.

CAMERA BASE

STATIONCCU

MONITO

R

SWITCHE

RSDI

COMPOSIT E

COMPONEN

T

BLOCK DIG. OF EQUIPMENT

ROOM



2. A/D CONVERTER : - This converter is provided to convert analogsignal into digital signal because switcher can accepts onlySDI (digital) video signal.

3. SWITCHER :- Switcher used in Doordarshan is PINNACLE PDS9000 and it costs 3crore and 20 lakh. All the outputs of VTR’S,

CAMERAS etc are given as input to switcher and the output of switcher is the final output to display.

RACK 3:-

1. LOGO GENERATOR :- The logo generator is used to generatelogo’s on T.V screen like

2. INTERNAL TALKBACK SYSTEM :-It is provided for internalcommunication between producer and cameraman.

3. PATCH CODES :-These are the wires used to facilitate easybypass for defective equipment.

4. TALLY DISTRIBUTOR :-The three cameras used in the studio aredisplayed in the PCR. The tally distributor shows whichcamera is on air or being recorded by glowing a light underthe particular TV.

RACK 4:-

1. T.V SCREEN : - It is provided to show the output.

2. WAVEFORM MONITOR : - It is a specially designed CRO toshow video waveform.

T.V

SCREEN

CAM 1 Tally light



3. IRD :-Integrated Receiver Decoders used to receive thesignal from the satellite and provide the QPSK demodulation to the received signal. It also separates thesignal into video and audio signal.

4. FRAME SYNCHRONIZER:-It is used to synchronize the outsidesignal coming from the satellite that is it converts thevideo signal into SDI (Serial Digital Interface) video signalbecause switcher can accept only SDI signal.

VIDEO BASICS

PRODUCING VIDEO

It begins with the lens system which focuses an image of the scene

onto a light sensitive surface within the camera head. In most

video cameras, the light sensor is a solid state CCD (chargecoupled device).

CCD

CCD is typically 12.5mm or 18mm across, and consists of hundreds

of thousands of tiny independent cells. Each cell develops an

electrical charge according to the strength of the light falling upon

it. The result is an overall pattern of electrical charges on the CCD,

that corresponds to the light and shade in the lens image.

To produce video signal scanning circuits continually read across

this charge pattern in a series of parallel path or lines(625).

Fluctuating voltage produced, corresponds to the strength of each

cell in turn. This is how a monochrome (black and white) camera

generates its picture.

In practical cameras which are colored (as in DDK Hisar) video

cameras use 3 CCD format. There are a number of variations too, in



the types of CCD used and their resolution. Top quality cameras

can resolve 700 vertical black and white stripes across the picture

width, simpler cameras may only be able to reproduce half the

number. Color fidelity is less accurate or consistent in simpler

designs, and there is a greater possibility of disturbing picturedefects. In best video cameras these are negligible.

RECREATING THE PICTURE

To convert the video signal back into the picture, use of either

picture tube or an LCD screen is done. Most TV receivers, picture

monitors, camera viewfinders, use picture tubes of various sizes.

In picture tube abeam of electrons scans across the screen,

causing its phosphor coated surface to glow. When the video is

strongest the screen will glow brightly at that point. Where there

is little light reflected from the scene, the scene will appear much

darker.

HOW THE CAMERA SEES THE COLOR

The color video camera relies on the additive color mixing process.

Any light sensor (CCD) can respond to the intensity of light. Itcannot distinguish between color. By placing red, green and blue

color filters over three light sensors the scene can be analyzed into

separate color components. In the color video camera the lens

image of the scene passes through a special prism, which splits

into three identical versions. Three CCD sensors with their red,

green and blue color filters provide three video signals

corresponding to the light and shade of these colors in the scene.



THE COLOR PICTURE

SCANNING

The scanning circuit read off the CCD charge pattern 60 times per

second. To reduce the flicker the odd lines are read first, then the

even lines. These odd and even fields are interlaced to form a

complete TV picture or frame. So the entire picture scanning

process using 525 lines, take place in 1/30 seconds. In a625 line

system there are 50 frames or picture a second.

SYNC PULSE

To reproduce the TV picture accurately, in full color, withouttearing, breakup, or picture roll, it is essential for the scanning in

the TV receiver or picture monitor to be exactly in step with

scanning in the camera. So regular synchronizing pulses are

combined with the video. These pulses need to pass through the

system accurately, to provide stable pictures.

There are two forms of sync pulses:

• Those that keep the horizontal or line scanning in

synchronization (line syncs)• Those that time the vertical scanning rate(frame syncs)



The video information together with its sync pulses (including an

additional color burst signal which stabilizes color accuracy), is

called composite video.

The sync pulse is produced by SYNC PULSE GENERATOR. It has the

following features:

• The horizontal and vertical drive pulses that initiate thescanning process.

• The blackening pulses that suppress the scanning read-off asit moves on the next line or frame.

• The sync pulses at the end of each line and each field.

• The color burst which provides a reference signal to stabilize

color fidelity when encoding color information with theluminance information.

• Sometimes a signal black burst is generated. Thisincorporates blanking, syncs, and black video level. This black burst signal is used as a synchronizing source, and equipmentis genlocked onto it.

GENLOCK

All equipment in a video system needs to work from exactly the

same synchronization pulses. Otherwise when shots are inter

switched (cut or combined) there will be picture disturbances such

as frame roll, displacement etc. To avoid this, sync pulses from the

video sources are used to synchronize all units via a genlock unit,

so that they scan in unison. Genlock unit may generate either a

standard NTSC (PAL, SECAM) signal over a signal conductor

combined Y and C or separate Y and C.

COLOR VIDEO

Although it is possible to transmit color from camera to screen in

the form of three separate color components red, green and blue

video signals – there are technical disadvantages.

When the American NTSC color TV system was developed, itsdesigners had to ensure that color transmission could also be



received on black and white receivers. This required some

ingenious engineering tricks which are also used in derived PAL

and SECAM color system.

Picture information was coded into:

Luminance(Y): This conveys the brightness and light and dark

screen.

Chrominance(C): This conveys the color in the screen.

The chrominance component is quite complex, for it has two

features: I signal (red minus luminance) and Q signal (blue minus

luminance) – in PAL system called U and V.

FORMULAE FOR LUMINANCE

Y= .3R + .59G + .11B

Where R, G, B represents red green and blue respectively.

If R=0, B=0, G=0 then the video is black and if R=1, B=1, G=1 thenthe video is black. There are three types of video which depend

upon Y, R, G and B:

Component video: Y, R-Y, B-Y

SDI video: Y,C(modulation of R-Y and B-Y)

COMPOSITE video: Y (modulation of Y and C)

Video Format NTSC PAL HDTV/SDTV

Typical Frequencies for Common TV and Computer Video Formats

Description Television format

for North America

Television for

South America,

High Definition/

Standard Definition



and Japan Europe and India Digital Television

Format

Vertical resolution

Format (visible

lines per frame)

Approx 480(525

lines per frame)

Approx 575 (625

total lines)

1080 or 720 or 480

18 different

formats

Horizontal

resolution Format

(visible pixels per

line)

Determined by

bandwidth; ranges

from 320 to 650

Determined by

bandwidth; ranges

from 320 to 720

1920 or 704 or 640

18 Different

formats

Horizontal

Rate (kHz)

15.734 15.625 33.75-45

Vertical Frame

Rate (Hz)

29.97 25 30-60

Highest

Frequency (MHz)

4.2 5.5 25

PRODUCTION CONTROL ROOM (PCR)

The generated signals in the studio are controlled and with some

effects and characters are added here.

The PCR usually of the various equipments like:-· Camera Control Unit (CCU)· Vision Mixer (VM)· Video Tape Recorder (VTR)· Audio Mixer (AM)

CAMERA CONTROL UNIT (CCU)



The camera control unit (CCU) is installed in the production control room

(PCR), and allows various aspects of the video camera on the studio floor

to be controlled remotely. The most commonly made adjustments are for

white balance and aperture, although almost all technical adjustments

are made from controls on the CCU rather than on the camera. This frees

the camera operator to concentrate on composition and focus, and also

allows the technical director of the studio to ensure uniformity between

all the cameras.

Main functions of CCU are:

• Control the iris, shutter speed.

• Adjust color balances- white balance & black balance.

• Monitor and adjust a wide range of technical parameters.

• Send signals to the camera operator.

• To digitally amplify the signal.

VISION MIXER



The vision mixer is the destination point for all picture sources in

the studio. The output of all studio cameras, video tape recorder,

caption scanners, character generator etc are fed to the vision

mixing unit. The vision mixing involves basically 3 type’s transition

between the above sources. These transitions are mixing wiping

and keying. The output of mixer desk is fed to transmission

monitor, Transmission chain etc. in production control area. The

vision –mixing panels offers a lot visual effects that require time,

skill & costly auxiliary equipments. Some of the facilities of vision

mixer are explained here.

THE CUT

The cut is an instantaneous switch from one picture to another. It

avoids the frame roll & flash evident, on picture at the moment of

flash evident, on picture at the moment of cutting.

THE MIX

The transition here is less pronounced. As the faders are operated,

the established picture fades away, while the new picture

progressively while transition. The mixing is illustrated.

THE FADE UP/FADE OUT



A selected channel can be fade up or fade out with the help of moving a fader up & down. The picture can be fade to black orfrom black.

THE SUPERIMPOSITION

Superimposition can be obtained by fading up two of more picturestogether. This may be used to add tilting to an existing picture orspecial picture or special montage effects.

PREVIEW

Vision mixers also have a preview blank & its output connected tomonitor. It enables us to check any selected non studio picturesbefore its translation.

THE WIPEThe wipe is common special effects. It can be described as onepicture chasing the original picture. The direction of entry of thepicture in original picture can be horizontal, vertical, diagonal,circular & so on.

KEYING

The keying signal can be generated either by the luminance orchrominance of source input. The keyed portion can be filled withthe same or with external portion or matte. Matte means internally

generated BG with choice of color from the vision mixer itself

CHROME KEYING

First figure shows original studio scene.



This figure shows computer graphics that will be used for chrome

keying.

This figure shows the result of the chrome keying.

Computer graphics is super imposed on blue back ground in studio

screen. IN this effect a selected portion of the back ground video

source is replaced with foreground video source. The FG portion tobe inserted is determined from a keying waveform, which may be



derived from the foreground picture. Sometime this is also called

as color separation overlay (CSO)

AUDIO MIXING CONSOLE

Any audio signal -either from mike or VTR is fed to it. Like vision

mixer, this is the instrument for the audio in which audio is

controlled. PCR has a 16-line console with control effect like gain,

attenuation, filtering and switching for the different input. The

video after the treatment on the vision mixer is sent to VTR &

suitable conversion or recording for the transmission through the

transmitter or the earth station.

PHONE IN CONSOLE

Phone in console is the simple telephone device attached with the

audio console. This device is used at the time of live studio

program to have live presence of home viewer.

TALK BACK SYSTEM

This is one audio loop attached to all the sections of Doordarshan

to communicate with different sections. This is just like intercom.



VIDEO TAPE RECORDER

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

the programs shot in the camera are simultaneously recorded in

the VTR. Also the VTR plays back all the videos as and when

required. Videos of prerecorded Events are queued up in the VTR

and are played back without a Break.

A video tape recorder (VTR), is a tape recorder that can record

video materialIn VTR we use the following video tape formats

1. DVCPRO50(Panasonic)2. BETACAM (Sony)

1. DVCPRO50(Panasonic)

This is a Digital video recording system that works by using a

digital rather than an analog video signal. The DVCPRO50 standard

doubles the coded video bit rate from 25 Mb/s to 50 Mb/s. Out of 5VTR used here,4 are DVCPRO50

2. BETACAM (Sony)

This is an analog video recording system that works by using a

analog rather than an digital video signal. Out of 5 VTR used here,

one is BETACAM. It uses higher specification metal tap which

increases its performance.



VECTROSCOPEAn oscilloscope used for checking the color accuracy of all parts of

the system (cameras, switcher, VCR, etc.). Wrong adjustments can

totally wreck color quality. White and black should be neutral,

producing a central blob screen. When the color bars test signal is

displayed, a series of e.g. six bright dots appear around the screen

– ideally within small engraved boxes.

WAVEFORM MONITOR

A waveform monitor is a special type of oscilloscope. It is typically

used to measure and display the level, or voltage, of a video signal

with respect to time. The level of a video signal usually

corresponds to the brightness, or luminance, of the part of the

image being drawn onto a regular video screen at the same point

in time. A waveform monitor can be used to display the overall

brightness of a television picture, or it can zoom in to show one or

two individual lines of the video signal. It can also be used to

visualize and observe special signals in the vertical blanking

interval of a video signal, as well as the color burst between each

line of video.



CHARACTER GENERATOR

A character generator, often abbreviated as CG, is used to produce

static or animated text for keying into a video stream. Modern

character generators are computer-based, and can generategraphics as well as text.

EDITING

After recording a raw material using video tape recorders(VTR)

different types of correction is done using edit suit like as cutting

unwanted video & audio, making suitable timing for Broad-casting,

program name, actor name, director name etc. and also edit new

audio & different types of video pattern, new images , new

pictures.

There are unit time for any program, therefore we need editing

thus we can see continuous picture in our television.

There are two types of editing

1. Linear editing

2. Non linear editing

1. LINEAR EDITING

It is simple type of editing. In this type we can use only one or two

Players & recorders .Different video clips that we want to add or join with main program are played into cassettes players, and



graphics that we want to add is selected to record on the tape. On

recorder the starting time and ending time is selected in between

which, mixing is done .Linear editing have disadvantage like it

takes more time. We can only add clip of length that we have

space on tape, means to add long clip, we can’t move video ontape, so overlapping occurs at that time. We can’t place more

images & pictures. Using linear editing we can interchange audio &

video only.

Other problems with linear tape based editing are:

• Editing in sequence-first shot first.

• Long hours spent on rewinding of tapes, Search of material.

• Potential risk of damage to original footage.

• Difficult to insert a new shot in edit.

• Difficult to experiment with variations

• Quality loss more in analog; even with digital

• Limited composing, effects, color, correction capability

2. NON LINEAR EDITING

• NLE is video editing in digital format with standard computer

based technology

• Computer technology is harnessed in random access,

computation and manipulation capability ,multiple copies

,Intelligent search, sophisticates projects and media

management tools, standard interfaces, and powerful display

• Flexibility in editing functions



• Easy to do change - 28 -s, undo, copy, duplicate and

multiple version

• Easy operation for cut, dissolve, wipes and other transition

effects

• Multilayer of video becomes easy

• Powerful integration of video and graphics. Tools for filtering,

color correction, key framing & special 2D/3D effects.

• Equally powerful audio effects and mixing.

• Possible to trim, compress or expand the length of the clip

•

Support for multi format. Multi resolution clips

• Intelligent and powerful 3D video effect can be created and

customized.

• Efficient and intelligent storage

Non linear editing is done on time line using PC based software.

The figure shows the window of NLE software.



Video editing is done using multilayer technique and audio mixing

is also possible on time line using multilayer.

Photo shows the time line of video gallery, preview window and

tool bar

Different clips of source programs are created and placed in

gallery. Items from the gallery can be used using simple drag &

drop technique.

There are so many in built mixing styles, transition, effects,

wrappings effects stored in the software that we can apply overtime line.

For comfortable viewing of time line over large space in horizontal

dimension, dual monitor technique is used in Doordarshan.



PC REQUIREMENT FOR NLE

• Intel Premium 2333 MHz processor(Higher recommended)

• PCI 2.1 complaint motherboard

• 128 MB or higher Ram

• 25 MB of available space hard drive space for drivers

• SCSI system driver recommended, with an additional SCSI

system drive for audio filed.

• Dedicated wide SCSI Av drive to store digital video files(at

least 18 GB)

• CD-ROM drive (SCSI drive recommended) standard keyboard,

three button mouse

• Super VGA display (at least 1024×786×24 bit true color)

monitor and accelerated graphics card (1152×864 or greater

recommended)

• Operating system: windows 2000 pro or windows XP

• NTSC or PAL video monitor

• Separate audio card is recommended for system sound

• VTR

• Speaker



EARTH STATION



INTRODUCTION



1) The c-band up link satellite earth station equipment is a

2.25KW. C-band uplinks operating in the frequency range of 5.85

GHz to 6.425GHz for transmit & 3.625 GHz for receiving signals.

The system is configured to operate in a fully digital environment

carrying simultaneously four MPEG2/DVC programs compressed &multiplexed as a single transport stream. This system comprises of

2.25KW high power amplifier, LNA redundant up converters change

over switch, digital equipment, video rack & audio processing

equipment, downlink hardware & power conditioning equipments.

2) The station electronics is located in the following racks namely

base band rack 1, base band rack 2,digital equipment rack,

receiving monitor rack, transmit rack &high power amplifier racks.

All the subunits are located in these racks to meet the functionalrequirements of smooth flow of audio, video RF & control signals.

3) A Network management system (NMS) is provided to control,

monitor & configure essential subsystems in the lineup. The power

conditionings have been configured totally uninterrupted operation

with redundancy &by pass features.

System Detail

The station has been designed to take four programs generated in

the studio room. These programs comprising of video & two audio

signals (stereo pair) are transported through a fiber optic link.

The transmit portion of the link is located in the studio & the

receive portion in the base band rack 1 & these modules are

connected using a fiber link optic cable. Totally four video & eight

audio signals are transportable. For the station, where the studio

facility & uplink facility is situated closed by, it is suggested to use

a direct interconnection of the video & audio to the base band rack by passing the fiber optical module. The interconnection from

studio room to the base band rack under as following:

Uplink Video Path



Of the four program of the fiber optic receive module, program 1 &

2 Processed in the base band rack 1 & program 3 & 4 are

processed in the base band rack 2. To have full flexibility in the

program, the program 1 & 2signals also fed as an additional input

to the program switcher router in the base band rack 2.Similarlyprogram 3 & 4 are also fed to the program switcher in the based

band rack 1. Hence video and audio interaction is established for

this purpose

Each program comprises of a video signal and two audio signals

which can be configured as dual mono or stereo audio. The video

are processed as cable equalization & suppression, the video

signals are fed to the 8*2 router (program switcher) for the

program selection. The selected video signal is fed to the video

processing amplifier for the sync regeneration & adjustment of video signal amplitude. Necessary video distributors are presented

in the path for monitoring video in the path. In addition the signals

are passed through video jack panel (VJP) which is use full in

bypassing fault modules in the lineup.

Uplink Audio Processing

IN similar lines of the video processing, the audio signals are also

first equalize & fed along with video signals to the 8*2 router(program switch). The selected pair of the audio signals is further

processed for limiting the amplitude of the audio signal to a

specified limit using the limiter. The limiter helps to limit the

amplitude of the audio signal in the actual program. Necessary

distributors are also provided in the lineup for monitoring the

audio signals .Audio jack panels (AJP) are also provided for ease of

bypassing faulty modules.

The amplitude of the audio signal is measured using the Audio

Monitoring Panel (AMP) which has necessary VU meters for

indication of audio level.

Each base band rack gives out two programs outputs, which are

fed to the Digital; Equipment racks as base band signals.

This consists of four MPEG2 video encoder, two multiplexer & two

modulators configured to operate as a 4.0 system. The multiplier

generates a singles transport stream to carry four compressed

program signals. The multiplexer output is fed to the modulator so

the modulator so as to perform QPSK modulation at 70 MHz IF

corrector. The complete system including the network



management is supplied by M/S Tandberg as a pre wired rack. Two

multiplexers & the modulator are provided are provided for

redundancy.

Up ConversionThe up conversion of digitally modulated IF signals is achieved first

by passing the IF carrier through a system equalizer in order to

correct the group delay and amplitude response of the complete

system including the satellite transponder. The equalizer output is

fed to the up converter so as to convert the IF carrier to the

transmitted “C” band carrier in the frequency range 5.85 to 6.65

GHz. Two set equalizers & up converters are provided along with a

redundancy controller to have redundancy for modulator, system

Equalizer, Up converter.

High power amplifier

The transmitted C band is amplified to 2.25KW power level in a

high amplifier rack to implement as a1:1 system.

The HPA rack comprises of two 2.25 KW HPA’s & a redundancy

controller for the 1:1 Redundancy operator.

Power Conditioning

The power for the operation comprises of Isolation Transformers

AVR, UPS power distribution panel. The ups are implemented as a

1:1 system. Due to the physical separation of the base band rack,

IF rack with respect to TX rack & HPA rack, two separate power

distribution panels are provided for the ease of distribution

MECHANICAL FEATURESThe earth Station electronics are housed in industry standard 19

inches conforming to IEC standards. The subsystems have been

located in various racks to take care of the convenient flow of

video, audio, RF, power & control signals. The racks are dust proof

& meet the specification of IP 54 ingress protection.



Construction Details and features of 19

inch rack

The rack has a frame which is made by welding “9 Fold sheet metalsections. The corners are strengthened by corner brackets. On to

this frame work various parts of the rack line front glass door, back

door, side covers, top & bottom panel are assembled 19” mounting

angler having perforated mountings holes are provided on the

front & back rear side of the racks. These mountings holes are

provided on the front & back rear side of the racks. These

mountings angles can be mounted at different positions. The

position of the mountings angles depend on the supporting angles

made out of deep drawn steel are also mounted on these

mountings which are used to support & guide the subsystems.

Space required in the front & rear side of the equipment & also the

dept. of the equipment, a set of supporting angles made out of

deep drawn steel sheets are also mounted on these mountings

angles which are used to support & guide the subsystems.

TECHNICAL DATA SUMMARY

Number of video inputs : fourVideo frequency range : 25 to

5 MHz

Video input level : 1V

Format : CCIR PALB 625

Impedance : 75 Ohms unbalanced

Return Loss : 20db

Number of Audio inputs : Eight

Audio input level : 0 db

Audio frequency range : 25Hz to 15 KHz

Impedance : 600 ohms

Uplink frequency : 5.8 GHz to 6.4 GHz

Downlink frequency : 3.7 to 4.2 GHz

Output Power : 22.52 transmit “C” frequencyIntermodulation : -22 dbc (with 4 db output back off)



AVR rating : 60KVA

Ups rating : 40 KVA

Parabolic dish antennas

Introduction

Parabolic dish antennas can provide extremely high gains at

microwave frequencies A2 foot dish at 10GHz can provide more

than 30db of gain. The gain is only limited by the size of parabolic

reflector; a number of hams have dishes larger than 20 feet, and

occasionally a much larger commercial dish is made available for

amateur operation, like the 150-foot one at the Algonquin Radio

Observatory in Ontario used by VE30NT for the 1993 EMEcontest.PDA consists of feed horn (works of receiving antenna) and

LNBC (low noise block converter) which acts as oscillator plus

mixer. PDA does amplification as well as generates IF(intermediate

frequency).



DISH ANTENNA DESIGN

A dish design works the same as the reflecting optical telescope.

Electromagnetic waves, light or radio, arrive on parallel paths from

a distance source and are reflected by a mirror to a common point,

called the focus. When a ray of light reflects from the mirror or flat

surface, the angle of path leaving (angle of reflection) is same asthe angle of the path arriving (angle of incidence). This optical

principal is familiar to anyone who misspent a part of youth at a

pool table. If the mirror is a flat surface, then two rays of light

leave in parallel, if the mirror is curved, two parallel incident rays

leave at different angles. If the curve is parabolic(y=ax2) then the

reflected rays meet at a point. A dish is a parabolic of rotation, a

parabolic curve rotated around an axis which passes through the

focus and the centre of the curve.Some of the difficulties found in

real antennas are easier to understand when considering atransmitting antenna, but are also present in receiving antennas,

since antennas are reciprocal. One difficulty is finding a point

source, since any antenna, even a half wave dipoles at 10 GHz is

much bigger in all directions, as the energy that was not radiated

toward the reflector would be wasted. The energy radiated from

the focus towards the reflector, just as a light bulb would. So we

are looking for a point source that illuminates only the reflector.

The energy radiated from the focus towards the reflector

illuminates the reflector, just as a light bulb would. So we are

looking for a point source that illuminates only the reflector

Amplifi

er

Mixer

Local

Oscillator

(5150MHz)

IF Band

950-

1450MHz

RF Signal

Block diagram of PDA



HIGH POWER TV TRANSMITTER

RECEIVING RACK

Receiving Rack composed of Integrated Receiver Decoder (IRD)

Equalizer, Line amplifier, Switching circuit and Monitor. Firstly, thesignal from the Parabolic Dish Antenna (PDA) is given to the IRD



where demodulation of signal takes place and separate visual and

aural signals are obtained. Further visual and aural signals are

applied to visual equalizer and aural equalizer respectively. From

the video equalizer, visual signal is given to the switching circuit

and from aural equalizer, signal is given to the Line amplifier andthen to the switching circuit. Finally, switching circuit output is

given to the Monitor and Transmitter.

GENERAL DESCRIPTIONTransmitter is mainly used to broadcast TV channels in a particular

area free to air as the signal is dispersed in that region and picked

up by directional antennas at home.

There are of two types of transmitter:

1. HTP (high power TV transmitter) has a range of 55km and a

power rating of 20kW and works on UHF (ultra high frequency).

PDA IRD VISUAL EQUALISER

AUDIO EQUALISER

LINE AMPLIFIER

SWITCHINGCKT

Satellite

Monitor

Transmitter

BLOCK DIAG. OF RECEIVER RACK



2. LTP (low power TV transmitter) has arrange of 15 km and a

power rating of 100W and works on VHF (very high frequency)

In DDK (Doordarshan Kendra) Hisar 20kW UHF TV Transmitter PCU-1320SSPQ1 is used build by NEC, Japan.

It is a set up to transmit two channels:

DD1(Channel 31)

Visual frequency 551.25MHz

Aural frequency 556.75MHz

DD2 (Channel 33)

Visual frequency 567.25MHz

Aural frequency 572.75MHz

PRINCIPAL CHARACTERISTICS

Power output

Visual:-20kW (sync. Peak)

Aural:-2kW

Frequency range: UHF band

Band 4 470-606 MHz (Channel 21 to

37)

Band 5 606-798 MHz (Channel 38 to

61)

Visual IF frequency : 38.9MHz

Audio IF frequency : 33.4MHz

Ambient requirements :-

Temperature Range : 0 to 45 C

Relative humidity : 90%max

Altitude : determined by the location



MAJOR FEATURES OF TRANSMITTER

1. High performance exciter

2. High efficiency cooling system

3. Compact size

4. High reliability

5. Excellent maintenance function

6. Ease of operation

MAJOR PARTS OF TRANSMITTER

1. Exciter

2. Power Amplifier



3. Power Supply



4. Dummy Load

5. CIB Diplexer

6. Liquid Cooling System



BLOCK DIGRAM OF TV

TRANSMITTER

EXCITER CIRCUIT

HPB 3090 exciter circuit chassis receives two input of both video

and audio signal incoming to the TV transmitter. Each chassis

contain same signal processing plug in bands by which the signal

are converted into IF modulated signal and aural modulated TVsignal. Exciter circuit has the following parts which are explained

later:

1. Aural modulator2. AD/DA converter3. DVC (Digital Video Converter)4. Visual modulator5. IF corrector6. Synthesizer7. VHF mixer

EXCITER

CIRCUIT

EXCITER

SWITCHING CKT

EXCITER

CIRCUIT

VISUAL

TR PA

AURAL

TR PA

CIB

DIPLEXER

TO

ANTENNA

POWER

SUPPLY

COOLINGSYSTEM

TRANSMISSION

CONTROL SYSTEM



UPPER HALF REPRESENTS THE SIGNAL FLOW GRAPH FOR MIXER

EXCITER CIRCUIT FOR MONOAURAL SOUND SYSTEM WHILE LOWER

HALF REPRESENTS THE OUTPUT SECTION

AURAL MODULATOR

VIDEO IN

A/D,D/A

CONVERTOR

VISUAL

MODULATO

R

IF

CORRECTOR

VISUAL

MIXER

V O/P

MONITOR

V AGC

INPUT

VIDEO

MONITOR

INPUT

MONITOR

F/B IN

REF IN SYNTHESIZER

650

Ω AURAL

MODULATOR

AURAL

MIXER750

Ω

A O/P

MONITOR

A AGC

INPUT

A MOD

MONITOR

AURAL

O/P

VISUAL

O/P

O/P

FILTER

HARMONIC

FILTER

C/B

DIPLEXER

O/P

ANTENNA

DUMMY

LOAD



It generates a frequency modulator and IF signal by modulating a

voltage controlled oscillator with an audio input. To fix average

frequency of the modulator oscillator at the reference input theautomatic phase controlled circuit is used.

DVC UNIT COMPENSATOR HPB 3103

It is composed of a non linear distortion compensating circuit,linear distortion compensating circuit, control unit etc, receives

the demodulated output signal of the transmitter and

automatically compensates for the distortion the output signal.

The non linear and linear circuits can be respectively bypassed.

AD/DA CONVERTER

The HPB-3102 AD-DA unit has functions that converts the

video i/p signal supplied to the exciter into a PCM signal and

sends the PCM signal to a unit for digital correction (HPB-

3103 DVC) and which converts the video PCM signal after the

digital correction into analog video signal and supplies the

analog video signal to a visual modulator unit(HPB-3104

VMOD unit).

IF CORRECTOR

The HPB-3105 IF Corrector unit , generally used for correction

of nonlinear distortion generated in the PA stage ,enables

correction of DG and DP characteristics of visual signal. This

unit also contains a means to combine two modulated. IF

carriers of the visual and aural , allowing multiplex operation

transmitter.



UHF MIXER

In HPB-3107 UHF Mixer unit, the local signal produced by

quadruple and IF signal is applied to a DBM to obtain an RFsignal. The RF signal is passed through filters (BPF and NF) to

separate out only the specified channel. Then, by amplifying

the signal to the required level, an RF signal of +20dBm is

obtained at the o/p. By applying AGC to the IF signal, the o/p

power of the transmitter is maintained at a constant level

.The BPF and NF are adjusted from the front side.

I/F Input Level=+10dBm

LO Input Level=+10dBm

Output Level=+20dBm

Bandwidth=8MHz

Visual modulator

The HPB-3104 visual modulator unit is intended to convert a

base band video signal into a modulated IF signal with the

ring modulator in which the IF carrier is also phase modulated

by a processed video signal to pre-correct the incidental

carrier phase modulation (ICPM).

SYNTHESIZER

The HPB-3108 Synthesizer unit generates two signals, visual

IF (VIF) and local

frequency.



Power amplifier

The UA-2000QC-S is a Power amplifier of peak output 2000 W,

which is used for visual of analog Transmitter.

The UA-2000QC-S is possible to use as a power amplifier of

1200W output for aural of analog Transmitter or a power

amplifier of 500W for digital Transmitter as well.

Power supply

Power supply is a switching type of stabilized power supply

that receives 400V AC (3 phase) and supplies +24~32V DC to

loads.

3-db coupler

3-dB Coupler is used for application listed below:

• Distributing one signal(2 o/p)

• Coupling 2 signals(1 o/p)

• Mixing 2 signals(2 o/p)

•Switching over 2 signals(2 o/p)



Cib diplexer

This unit is used to combine visual and aural signals.

Operating principle:- The signal of the aural transmitter

applied at terminal (1) of the 3-dB Coupler H1 appears at

terminals (2) and (3) with the same amplitude with a phase

difference of 90 degree (terminal (2) is 270 degree ahead in

phase of

terminal (3)), because of the nature of the 3-dB Coupler. No

output appears at terminal (4).

The signals appearing at terminals (2) and (3) then pass

through aural band pass filters respectively and reach

terminals (2’) and (3’) with 90 degree phase difference are

combined in the H2 into terminal (4’) because the signal at

terminal (2’) has a 270 degree lead phase from that at

terminal (3’) but no o/p appears at terminal (1’). The signal is

appearing at terminal (4’).

Meanwhile, the visual transmitter o/p is connected to

terminal (1’) of the 3-dB Coupler H2. The visual signal

entering this terminal does not appear at terminal (4’), but at

terminals (2’) and (3’) with the same amplitude and with a

phase difference of 90 degree (terminal (2’) is 270 degree

ahead in phase of terminal (3’)).

The visual signals are reflected at points A and B, then

reaching terminals (2’) and (3’) of the 3-dB Coupler H2. Since

the length of point A to terminal (2’) of H2 is equal



electrically to that of point B to terminal (3’) of H2, the visual

signal returning to terminal (2’) of H2 is combined with that

to terminal (3’) because of the nature of 3-dB Coupler. Then

the combined visual signal appears at terminal (4’).

Liquid cooling system

This system is composed of pump rack and heat exchanger in

addition to the transmitter.

The pump rack is equipped with automatically switch able

dual pumps thus realizing high redundancy accuracy. This

pump rack is composed of pumps, a coolant tank, control

panel and power supply. Two pumps are used pump A and

pump B for each rack out of which one is used at one time.

In a region where outside air temperature never becomes

lower than 0 degree Celsius purified or distilled water is used

as coolant having PH range =6.5~8.5.

In a region where temperature is less than 0 degree Celsius

antifreeze use pure ethylene glycol containing no impurity

diluted with water and mix it with the corrosion inhibitor.



ANTENNA

ANTENNA TYPE

Doordarshan /TV transmitting antenna is a Radio Frequency

system Pty Ltd (RFS) transmitting antenna model PHP322D. The

antenna is capable of multi channel operation & can accept a no. of

UHF TV transmitters within the 470-860 MHz range. The antenna

has been optimized in the factory for channels E31 (550-558 MHz)& E33 (566-574 MHz) & the frequency range 500-650 MHz



ANTENNA IDENTIFICATIONPHP 32 D

Panel Antenna Horizontal

Polarized

Thirty two panels

Four Sides

ANTENNA INPUT CAPACITY

The system has been designed to accommodate 2*20 KW PAL

transmitters into half antenna.

MECHANICAL CONSTRUCTION

The array consists of a series of thirty two panel antenna. There

are two antenna ladders to access the antenna for installation &

maintenance. Lighting protection is to be installed on top of

column.

ENVIRONMENTAL CONDITIONS

• Temperature operating : -10 c to 50 c

•Design wind speed : 240 Kilometer per hour

• Total Wind Load @ 50 m/s: Normal to Face =25 Ka

ELECTRICAL CHARACTERISTICS

• Model : PHP32D

• Operating Frequency range: CHE31 (550-558 MHz)

CHE33 (566-574MHz)

• Polarization : Horizontal



• Max Power rating : 40 KW peak sync into Half

antenna

• Design Power rating : 2*20 KW Peak Sync

best final ddk hsr both

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