“Industrial Training”

AT PRASAR BHARTI BHOPAL MP

Submitted in partial fulfillment of the requirement for the award of Degree of Bachelor of

Engineering in Electronics & Communication

Submitted to

RAJIV GANDHI PROUDYOGIKI VISHWAVIDHYALAYA BHOPAL (M.P.)

Submitted By

Varun Shrivastava 0111EC091113

Under the supervision of

Mr. P. K. Pati (Engg.)

Department of Electronics and Communication Engineering

Technocrats Institute of Technology, Bhopal

ACKNOWLEDGEMENT

I am extremely grateful and extend my sincerest thanks to Dept. of

Doordarshan Kendra, Bhopal M.P. for providing me with an excellent working

environment, so that I could work uninterruptedly and complete the project within

due date.

I also express my sincerest thanks and gratitude to the complete staff of

Doordarshan Kendra, Bhopal M.P. under whose able supervision, valuable

guidance, and all possible assistance, I successfully completed my vocational

training and subsequent compiled this report.

I also express my sincerest thanks to Mr.P.K.Pati DDG(E) and Mr.R.K

Bajpai (Asst. Engineer) of Doordarshan Kendra, Bhopal M.P. without whose

assistance the above would not have been possible.

I am also thankful to my HOD EC Department Prof. Vikas Gupta for

giving opportunity and encouragement for doing the Vocational Training.

INDEX

1. Introduction

2. Basic unit description

3. Detailed discretion

a.Studio center

b.Active area

c.CCU

d.Production Control Area

e.Video Tape Recording

f.Control Apparatus Unit

4. Usefulness

5. Summary

6. Conclusion

INTRODUCTION

Doordarshan Kendra is a television program production and telecasting

center. A fully fledged Doordarshan Kendra consists of studio and transmitters. In

television both the picture and sound are transmitted. This makes television

program production a complex affair.

Television stated in India as an experimental service in 1959. However, long

and regular general service of television was started in August in 1965. National

program was introduced over a entire network with effect from 15/08/1982. At the

same time it introduced in a phased manner. The first telecast in color was an

Independence Day function on 15/08/1982.Till 31/01/1992 Doordarshan had high

power transmitter .371 low power transmitter, 76 very low power transmitter

covering 78.7% of the population. Now a day‘s number of power transmitters has

increased with the tremendous demand for additional software facilities. To meet

the requirement off diverse software objectives, a three tire service as under has

been implemented.India adopts CCIR 625 PAL B television systems. In this

system the picture system is amplitude and sound signal frequency modulated

before transmission. The carrier frequencies are suitably spaced and the modulated

outputs radiated through a common antennal. Thus each broadcasting station has it

own frequency and a receiver can be tune to select any desired station.

Doordarshan, the national television service of India, is one of the largest

broadcasting organizations in the world in terms of coverage and the infrastructure

of studio and transmitters. Today‘s broadcasting major had a modest beginning

with the experimental telecast starting in Delhi in 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 a second city –

Mumbai only in 1972. Till 1975, only seven cities were covered by Television.

Doordarshan was separated from AIR in 1976.

Doordarshan operates 30 channels – five All India channels. One Parliament

channel, Eleven Regional Language Satellite channels, Eleven Hindi belt Network,

Gyandarshan (Educational channel) and one International channel. Besides this,

Doordarshan has DTH service ― DD Direct Plus‖.

The first experiment in satellite technology in India was conducted in 1975-

76 under the programme Satellite Instructional Television Experiment (SITE). This

was incidentally, the first attempt in the world to use satellite broadcasting for

social education. Colour transmission was introduced during the Asian Games held

in New Delhi in 1982. Doordarshan then proceeded to install transmitters

nationwide rapidly for terrestrial broadcasting. In camera tube the conversion of

optical information to electrical form and its transmission are carried out element

by element one at a time sequential manner to cover the entire scene which is to be

televised.

There remain approximately 10 regional stations which operate in areas not

included within the present 75 per cent population coverage. Even if coverage was

extended as far as 87 per cent, some regionals would still be outside such coverage.

If the present terrestrial footprint was extended it may offer further opportunities

for regional broadcasters who are currently outside the current footprint. Any

extension would need to be supported by a business case assessing the related costs

and benefits. Areas of future extension would be to less heavily populated areas

with smaller potential audiences for broadcasters and higher costs per viewer. The

extension of the present terrestrial footprint by the present licensees seems unlikely

to be commercially viable in the present economic circumstances. Any

Government support would therefore need to be weighed against other

government priorities and the benefits to be gained from any extension; and the

availability of funding cannot be assumed.

Extension of the footprint also becomes increasingly unlikely as the country

moves closer to a DSO date. At present there are around 60 per cent of viewers

who are watching a digital service, and as DSO nears the other 40 per cent will

gradually adopt digital reception. Viewers in areas outside the terrestrial footprint

will only have the option of satellite reception, so as digital take-up increases, this

would further weaken the case for extension of the terrestrial service. That is,

households outside the existing coverage will already have purchased satellite

television equipment

BASIC UNIT DISCRIPTION (WEEKLY)

a) 1st week

Primary Services

Each major state is to have its own primary service produced at state capital

on the language of the state to be available throughout the state.

National Services

The programs for the nation T.V. Service are the mainly produced at Delhi.

Besides programs produced at other regional centers are also used for the service.

National services is already available throughout the country utilizing S band

transponders of INSAT and the existing microwave links.

Television

India adopts CCIR 625 PAL B television systems. In this system the picture

system is amplitude and sound signal frequency modulated before transmission.

The carrier frequencies are suitably spaced and the modulated outputs radiated

through a common antennal. Thus each broadcasting station has it own frequency

and a receiver can be tune to select any desired station.

Picture Transmission

The Picture information is optical in chapter and may be thought of assembly of

large no. of bright and dark areas representing picture details. These areas may be

called as picture elements.

In camera tube the conversion of optical information to electrical form and

its transmission are carried out element by element one at a time sequential manner

to cover the entire scene which is to be televised.

The output from the last if stage is demodulated to recover the video signal.

This signal that carries picture information is amplified and coupled to the picture

tube which converts the electrical signal back into picture element of the same

degree of black and white. This glass envelop contain an electron guns produces

beam of electrons aimed at the fluorescent screen. nick of the tube.

The amplitude of the current in the horizontal and vertical deflection

coils.When the electron beam strike the screen light is emitted. The beam is

deflected by a pair of coils mounted at theso adjusted that the entire screen called

raster gets illuminated because of the fast rate scanning.

The video signal is fed to the grid or cathode of the picture tube. When the

varying signal voltage makes the control grid less negative, the beam current is

increased making the spot of light on screen brighter and vice versa. The rate at

which the spot of light moves is so fast that the eye is unable to follow it and also

so a complete picture is seen because of the storage capacity of the human eye.

Sound Reception

The path of the sound signal is common with the picture signal from antenna

to the video detector section of the receiver. Here the two signals are separated and

fed to the respective channels. The frequency modulated audio signals is

demodulated after at least one stage of amplification. The audio output from FM

detector is given due amplification before feeding it to the load speaker.

Synchronization

It is essential that the same co-ordinates be scanned at any instant both at the

camera tube target plate and the raster of the picture tube otherwise picture details

or would split and get distorted. To ensure perfect synchronization,

synchronization pulses are transmitted during retrace in fly back intervals of

horizontal and vertical motions of the camera scanning beam. Thus in addition to

carrying picture details the radiated signal at the transmitter also contains

synchronizing pulses. These pulses which are distinct for horizontal and vertical

motion control are processed at the receiver and fed to the picture tube sweep.

Scanning of the elements is done at a very fast rate and this process is

repeated a large number of times per second to create an illusion of simultaneous

pickup and transmission of picture details. A camera tube is used to convert the

optional information into a corresponding electrical signal, the amplified of which

varies in accordance with the variation of brightness.

The object to be televised be focused by a lens assembly on a rectangular

glass plate which has a very thin layer has a very high sensitive when no light falls

on it. According to the brightness of image the conduction of each element of

photo layer changes accordingly.

An electron beam is used to pick up the picture information now available on the

target plate in terms of varying resistance at each point on its way the beam is

deflected by a pair of deflecting coils kept mutually perpendicular to each other to

achieve scanning of a entire area. Scanning is done in the same way. The magnetic

deflection caused by the current in one coil gives horizontal motion to the beam

from left to right at a uniform rate and then brings it quickly to the top of plate to

start the procedure all over again.

As the beam moves, than element to element it encounters a different resistance

across the plate, depending on the resistance of photo conductive coating the result

is a flow of current which varies in magnitude as the element across of the

resistance Ri and this corresponds to the optical varying voltage picture. The

electrical information obtained from the T.V. camera tube is modulated career

frequency .The modulated output is fed to the transmitter antenna for radiating

along with sound signal.

Sound Transmission

The microphone converts the sound signal into proportionate electrical signal

which is normally a voltage. The audio signal from microphone after amplification

is frequency modulated, employing the assigned carrier frequency. Output of the

sound FM transmitter is finally combined with AM picture transmitter output

through a combining network and fed to a common antenna for radiation of energy

in the term of electromagnetic waves.

Transmiter

The one volt p-p video signal and 10dBmbalanced audio signal from master

switching room (MSR) are fed to transmitter to transmit the signal into air. The

10KW transmitter can cover 80Km of air distance around Bhopal. Transmitter

compact in construction and the design employees and state of art techniques and

devices. The principal features of this transmitter are:

1. Solid state exciter

2. Control unit

3. Solid state power amplifier

4. Audio power amplifier

Video power amplifier

Video last power amplifier

IF unit

Up-converter unit

D G corrector

The IF unit consists of:

1. Video processor

2. Visual modulator

3. IF synthesizer

4. ICPM corrector

5. Rectifier and regulator board

6. Display board

7. CIN Diplexer

BLOCK DIAGRAM

Fig-Block Diagram of 10kW TV Transmitter

The video signal from MSR passed through hum suppressor to suppress any hum

in the line then fed to video equalizer to signed they feed to the switcher. Output of

the switcher routed to exciter through STAB (color establishing unit) to adjust the

various parameter .The 10dBm audio signal from MSR is fed to switcher from it is

routed through limiting amplifier /program amplifier. Two attenuator are provided

on console for attenuation of the signal.

VU meters are provided for monitoring the audio level from LA/PA the

audio signal feed to aural exciter section. For monitors video signal on waveform

monitor and vector-scope after switcher monitor are provided at various state for

monitor signal level.

Similarly loud speaker s provided at various stages to monitor audio level.

Antenna

The output of VLPA stage is fed through co-axial feeder into a combine

network is CIN (constant impedance notch). Duplexer where the output from the

FM sound transmitter is added to it. This network is designed in such a way that

while combining either signal doesn‘t interfere with the working of the other

transmits. A coaxial connects the combined output to the antenna system mounted

on a higher tower situated close to me transmitted. A turnstile antenna array is used

to radiate equal power in all direction. The antenna is mounted horizontally for

better signal to noise ratio.

Fig- Antenna

b) 2nd

week

OBJECTIVES OF DOORDARSHAN STUDIO

1) To originate programmes from studios

2) To knit various sources of programs i.e., camera output, OB out, M/W, VTR

out, video graphics and characters generator etc.

3) Processing / distribution of different sources.

4) Routing of programme for recording/ transmission via MSR and Micro Wave.

BLOCK DIAGRAM

FIG-VIDEO CHAIN OF A DOORDARSHAN STUDIO

Activities in a Television studio can be divided into two major areas such as :

1) Action area (Studio)

2) Production control room (P.C.R).

Action area

a. This place requires large space and ceiling as compared to any other

technical area.

b. Action in this area includes staging, lighting, performance by artists, and

arrangement to pick up picture and sound.

c. Typical size of TV Studio is 20 x20x8.5 cubic meters

Hardware provided in this area include:

a. Monitoring facilities for all the input and output sources(audio/video).

b. Remote control for video mixer, and special effect (ADO) etc.

c. Communication facilities with technical areas and studio floor.

d. Vision mixing and switching

e. Character Generator (CG)

f. Sync Pulse-Generator (SPG)

g. Camera Control Unit (CCU)

h. Light Control.

i. Audio mixing and control

j. Video Tape-Recorder

k. Electronic Still Storage System

l. Post Production Suites

Vision mixing and switching

Unlike films, television media allows switching between different sources

simultaneously at the video switcher in Production control room operated by the

Vision Mixer on the direction of the program producer. The producer directs the

cameramen for proper shots on various cameras through intercom and the vision

mixer (also called VM engineer) switches shots from the selected camera/cameras

with split second accuracy, in close cooperation with the produce. The shots can

be switched from one video source to another video source, superimposed, cross

faded, faded in or faded out electronically with actual switching being done during

the vertical intervals between the picture frames. Electronics special effects are

also used now days as a transition between the two sources.

Fig- video mixing

Ampex Digital Optics (ADO-2000)

ADO is a very useful aid to production. 30 preset effects can be recalled

through the keyboard. Various picture manipulations are possible. The picture can be

compressed, size can be reduced and cropped into another picture. The principle of

operation is that the input Video is converted in digital form using A/D and then the

digits are manipulated to create the desired effects and then it is converted back to

analog form using D/A.

Character genrator

Characters Generators are provide titles and credit captions during production

in Roman script. It provides high resolution characters different colors for colonizing

characters, background, edges etc. At present bilingual and trilingual C.G are also

being used by Doordarshan.

Character Generator is a microcomputer with Texts along instructions when

typed in at the keyboard is stored on a floppy or a Hard disk. Many pages of scripts

can be stored on the disk and recalled when needed, by typing the adresses for the

stored pages, to appear as one of the video sources.

Central apparatus room

This is the nerve center for a television station. Activities in this area

include:

1 Distribution of stabilized power supply to different technical areas with

protection devices.

2.Sync pulse generation and distribution.

3 Distribution of sources to various destinations

4. Video processing and routing.

5. Electronics for camera chain, video switchers, special effect generator.

6. Monitoring facilities

7. Patch panel for video and audio lines

8. Electronics for micro wave links

Sync Pulse-Generator

It is essential that all the video sources as input to the switcher are in

synchronism i.e., start and end of each line or all the frames of video sources is

concurrent. SPG is normally duplicated for change over in case of failure.

Light Control

The scene to be televised must be well illuminated to produce a clear and

noise free picture. The lighting should also give the depth, the correct contrast and

artistic display of various shades without multiple shadows.

The lighting arrangements in a TV studio have to be very elaborate. A large

number of lights are used to meet the needs of ‗key‘, ‗fill‘, and ‗back‘ lights etc.

Lights are classified as spot and soft lights. These are suspended from motorized

hoists and telescopes. The up and down movement is remote controlled. The

switching on and off the lights at the required time and their dimming is controlled

from the light control panel inside a lighting control room using SCR dimmer

controls. These remotely control various lights inside the studios

Modern TV studios have a computer-controlled lighting system the intensities of

various lights can be adjusted independently and memorized for reproduction. The

status indication of lights regarding their location and intensity is available on a

monitor/MIMIC display. During reproduction of a particular sequence, the

information from the memory operates the respective light dimmers. Hand held

control boxes are also available for controlling light intensities inside the studios

which communicate via a control panel. Most of the operational controls of the

computerized light control system can also be performed manually with the back –

up matrix and fadder controls.

Video Tape recorders

VTR room is provided at each studio center. It houses at least two console

type 1‖ videotape recorders (VTRs) and a few Broadcast standard Videocassette

recorders (VCRs). In these recorders, sound and video signals are recorded

simultaneously on the same tape.

ACCESS TO ELECTRONIC STILL STORAGE SYSTEM

Some PCRs have access to the electronic still storage system. One replay

remote control of the digital library system is mounted on the video production

control table at the PCR. Still pictures stored in the library system can be recalled

and used in production by selecting them by their addresses either from the local or

from the remote control pannel after recomposing if desired.

Video chain

Output from the switcher goes to stabilizing amplifier via PP and VDAs.

Output from the stab. Is further distributed to various destinations. It may be noted

that the use of VDAs helps to monitor the video signal at different locations and

the use of PP is very helpful for emergency arrangements during breakdowns and

trouble shooting.

A separate monitoring bus is provided in CCU, LCU and END CONTROL

with sources as shown. END CONTROL also has a remote for the adjustment of

levels etc. in the STAB AMP unit. Route for the other sources is similar to this

and can be understood from the block schematic.

SYNC Pulse Generator

Television signals for broadcasting are originated by cameras and telecines,

recorded and replayed by video tape recorders, mixed in studio vision mixers and

finally distributed for transmission. Fig. shows the use of sync pulse generator for

generating colour composite video signal (CCVS).

Black Burst (BB)

This pulse contains all the pulses except active video information. It

contains pulses H, V, A, S K, P & SC. This pulse can be decoded back to

regenerate these pulses back. Most of the equipment now a days are using this

single pulse from SPG instead of several pulses. This allows us to have single

distribution network for synchronising pulses.

Each source needs its own SPG. This is true if it has to work in a standalone

environment. Where several cameras work together, as in a studio, it is better to

use a common SPG. Characteristics of these waveform has specified durations,

levels and rise-times, etc. The more stringent specifications cause complex and

costly generator.

One generator serving a number of sources is a better option than many

separate generators. It is also important that the signals from the various camera

match time-wise. This is easier to achieve if they all had same generators.

Pulse Distribution

With only one SPG centrally located a mechanism of pulse distribution is

required. With each and every 75 ohm destination requires a dedicated 75 ohm

source.

If this is not done then cables will be incorrectly terminated, signals will

have the wrong amplitude and will suffer from reflections. Use of PDA provides

multiple feed to various destinations.

Pulse Distribution Amplifiers

These amplifiers have a high input impedance (around 10 K typically) and a

number of 75 ohm outputs. 10 outputs are typical for a pulse distribution amplifier

(PDA). The PDA consists of an amplifier with very low output impedance, less

than 0.1 ohm. It is capable of generating a considerable signal current (1V into 75

ohm is a peak signal current of 14 mA). This high current, low impedance, output

is distributed to the various separate outputs by 75 ohm resistors. It is these

resistors which determine the output impedance.

Video distribution Amplifiers

Video is distributed in the same way as pulses. Video signals are distributed

by 75 ohm circuits, consequently separate distribution amplifier (DA) outputs are

needed for each. Vision DAs are usually much more sophisticated than their pulse

counterparts having performance up to 5.5 MHz with minimum impairment to the

signal. The distortion introduced by a DA should be immeasurably small as the

signal passes through the distribution system.

Video equalisers

Co-axial Cable has resistance, capacitance and inductance. It will therefore

introduce losses to the signal particularly to the higher frequencies. This is

undesirable and hence a suitable correction is carried out by equalizers. These are

reactive circuits which basically introduce an equal and opposite frequency

characteristic to that of the cable. For short cables upto 50 meters of length, simple

equalisers are used. The basic tie line equalizer is a passive device and can only

introduce more loss

Consequently such an equaliser is designed to reduce all frequencies to the same

level, they are amplified again to regain level.

It is assumed that the total loss of such equalizer and cable is no more than 6

dB. Distribution amplifier also provides the necessary gain - in this case 6dB.

(This is in addition to the termination loss of 6 dB required of all amplifiers driving

into 75 ohms)

OB Signals

OB Signals are not synchronized with the station and hence they are non

synchronized sources. In order to mix OB signal with other sources it has to be

made synchronous with the station sync. There are two methods which can be

used to make them synchronous.

a) Gen-lock

b) Frame synchronizer

Gen-lock is short for generator lock. The sync pulse generator providing the

station pulses is referenced to the contribution video from the OB. It uses internal

timing comparators to force its output timings to match those of the input video.

The principle limitations of Gen-lock is that only one outside source can be made

synchronous at a time. The alternative approach, using a synchronizer, does not

suffer from this disadvantage.

Gen-Lock SPG

Sync Pulse Generator can be synchronized to an external video signal by

referencing the sync pulse generator supplying the studio to the external signal.

Similar arrangements apply in respect of Black Burst installations. Where each

area in a studio complex has its own sync generator. A reference signal (usually

black and burst) is distributed to all the generators to maintain synchronism

between them.

Stabilising Amplifier

Stabilising Amplifier is placed at the end of the studio chain. As the video

signal from the source has traveled to various D/A, switchers and other processing

equipment before it comes to the stab. amplifier, it might have suffered some

impairment etc., As synchronizing pulses are very important for the locking of TV

receiver scanning oscillators, it is better to clean it. Stab. Amplifier provide the

following :

a) Clipping the sync. Pulses at 50% level, regenerate them and then fix them

back to the video signal.

b) Provide end control for the adjustment of various levels like video level,

chroma level, sync. Level, burst level and chroma phase level etc. It is also

possible to adjust these controls from a remote location.

3) 3rd

week

VIDEO Video is the technology of electronically capturing, recording, processing,

storing, transmitting, and reconstructing a sequence of still

images representing scenes inmotion.

History

Video technology was first developed for cathode rat

be(CRT) television systems, but several new technologies for video display

devices have since been invented. Charles led an Ampex research team developing

the first practical video tape recorder (VTR). In 1951 the first video tape recorder

captured live images from television by converting the camera's electrical impulses

and saving the information onto magnetic videotape.

Video recorders sold for $50,000 in 1956, and videotape cost $300 per one-hour

reel.[1]

However, prices steadily dropped over the years; in 1971, Sony began

selling videocassette (VCR) tapes to the public. After the invention of the DVD in

1997 and Blu-ray Disc in 2006, sales of videotape and tape equipment

plummeted.Later advances in computer technology allowed computers to capture,

store, edit and transmit video clips.

Characteristics of video streams number of frames per second

Frame rate, the number of still pictures per unit of time of video, ranges

from six or eight frames per second (frame/s) for old mechanical cameras to 120 or

more frames per second for new professional cameras. PAL(Europe, Asia,

Australia, etc.) and SECAM (France, Russia, parts of Africa etc.) standards specify

25 frame/s, while NTSC (USA, Canada, Japan, etc.) specifies 29.97 frame/s. Film

is shot at the slower frame rate of 24photograms/s, which complicates slightly the

process of transferring a cinematic motion picture to video. The minimum frame

rate to achieve the illusion of a moving image is about fifteen frames per second.

Interlaced vs progressive

Video can be interlaced or progressive. Interlacing was invented as a way to

reduce flicker in early mechanical and CRT video displays without increasing the

number of complete frames per second, which would have required sacrificing

image detail in order to remain within the limitations of a narrow bandwidth. The

horizontal scan lines of each complete frame are treated as if numbered

consecutively and captured as two fields: an odd field(upper field) consisting of the

odd-numbered lines and an even field (lower field) consisting of the even-

numbered lines.

Analog display devices reproduce each frame in the same way, effectively

doubling the frame rate as far as perceptible overall flicker is concerned. When the

image capture device acquires the fields one at a time, rather than dividing up a

complete frame after it is captured, the frame rate for motion is effectively doubled

as well, resulting in smoother, more life-like reproduction (although with halved

detail) of rapidly moving parts of the image when viewed on an interlaced CRT

display, but the display of such a signal on a progressive scan device is

problematic.

NTSC, PAL and SECAM are interlaced formats. Abbreviated video

resolution specifications often include an i to indicate interlacing. For example,

PAL video format is often specified as 576i50, where 576 indicates the total

number of horizontal scan lines, i indicates interlacing, and 50 indicates 50 fields

(half-frames) per second.

AUDIO SIGNAL

An audio signal is a representation of sound, typically as an electrical

voltage. Audio signals have frequencies in the audio frequency range of roughly 20

to 20,000 Hz (the limits of human hearing). Audio signals may

be synthesized directly, or may originate at a transducer such as a

microphone, musical instrument pickup, phonograph cartridge, or tape

head. Loudspeakers or headphones convert an electrical audio signal into sound.

Digital representations of audio signals exist in a variety of formats.

VIDEO MEASUREMENT

Video measurement is a very important part of video production in

doordarshan or in any broadcasting system.The transmission of Television signal

can be termed as wave form transmission. The signal passes through many

equipment and it gets amplitude/phase distorted. Engineers who are operating and

maintaining the equipment are supposed to monitor and make regular checks and

corrections at periodical intervals so that the received signal is distortion free. For

making evaluation of video we normally use two methods and they are

1. Objective evaluation

2. Subjective evaluation.

Each has its own merits and demerits and both combined together form an

effective tool to judge the quality of the picture. In the Objective evaluation

method normally a standard wave form is sent and the received wave from is

compared for deviations from the original. This is called wave form comparison

method. The other method is the sweep frequency method and popularly used for

evaluating the frequency response of the transmitter. Whenever we think of video

measurement or test signal immediately we think about the pulse and bar signal.

Fig- video measerment

Since long time square wave is being used to find the response of any

equipment as it is very easy to generate and convenient to use.

In Television also it is no exception. The figures given below illustrate a

fairly good account of the effect of the deteriorations on the shape of the bar.The

duration of the bar signal is 25 m sec. (one half of the active line period) in full

field signals and 10 m sec. in ITS.

S/N Ratio

Noise can be defined here as a generic name for all the various forms of

unwanted voltages which modify the signal during the course of transmission from

one point to another. Whenever we say S/N ratio normally we mean the continuous

random noise measurement only. The random noise takes the form of quasi

infinite series of short pulses whose amplitudes and instants of occurrences are

random.

The S/N Ratio = 20 log 10 (Ep/Em)

Where Ep = peak to peak Signal voltage and Em = RMS noise voltage.

Normally the peak to peak Signal voltage will be 0.7 volts

As you might be aware that higher luminance frequency components are

subjectively less visible. So some people felt that you should simulate the

response of the eye to get the true picture by introducing filters to filter out noise

voltages of frequencies beyond 8 or 10 MHz. So a weighting filter is introduced

which simulates the response of the eye. This is known as weighted S/N ratio.

This is normally more than the unweight S/N ratio.

Fig-s/n ratio

4) 4th

week

OB VAN

Since 1998 we have been the biggest integrator and supplier of the TV and radio OB

Vans in the Czech Republic as well as mobile TV satellites and terrestrial links for

broadcasting, production and distribution companies. Over the course of time we have

provided our customers with a great deal of deliveries ranging from the small vans to

the custom-made coach buildings on the multi-tonne chassis or semi-trailers. The

assembly of the OB Vans takes place in our new assembly hall in our manufacturing

area. It has a capacity for a simultaneous assembly of two large OB Vans, or four to

six small ones

OB Van is equipped with 8 nos of Thomson TTV 1657 Digital CCD cameras,

16 input versatile vision mixer ROSS Synergy with various special effects. 16 channel

Sound Craft make audio mixer with facility of individual channel equalization and

limited. In addition to the above, one computerized MOVE CG for supering titles.

Two nos. of broadcast quality VCR having slow motion (TTV3575p), two nos. of

Recording VCRs and one EVS make Live slow motion hard disc recording system is

also installed. One Long haul microwave link is also available with OB Van.

Fig- Ob van

5 camera OB/SNG van

Vehicle Mercedes 814D, 1994,140HP, 280.000km

Weight 8,4T, L: 6,33 m, W: 2,2m, H: 3,5m

Power

32A 400V. CEE

HF:

1x Antenna Vertex 1,8m

1x Downconverter PMCA SDC 50

1x Poleswitch Nortel Dasa

1x Antennacontrol Vertex 7031

1x Spectrum analyser Tektronix 2712

1x TV modulator Barco TVDM 40

2x HPA Nortel Dasa 300W KU Band

1x HPA switch Mitec MC2724

2x Upconverter Nortel Dasa

Digital modulator Radyne ComStream DM-180

5-40 Mbps

2x DVB encoder Thomson DBE 4110 4:2:2/4:2:0

Analog/SDI

Encryption:

BISS1, BISS/E/buried ID, injected-ID

1x Digital satellite receiver Kathrein

2x Digital satellite receiver NDS, Scopus

1x Kathrein SAT splitter

Video

1x Sony DFS-700 8ch. digital videomixer

1x Videogenerator Grundig VG1100

1x WFM Tektronix 1741A

8 Sony monitors LMD 9030 9"

1x Sony monitor LMD 1430 14"

Audio

1x Yamaha O3D,digital 16ch. mixer

2x Meter NTP 277-400

2x Speaker K&H

Intercom

2x D-net

2x Telephone hybrid (analog)

1x Intercomunit , 5 stations

2x Cameraring, production and engineer

1x Motorola basstation

4x Motorola walkie talkies

1 Drake intercomstation for connection with OB van.

Cables

1x 150m audio multicore (10x)

1x 100m video (SDI)

AVA has recently evolved into one of the biggest production companies in

Croatia. With future projects in mind, they ordered an OB van from AVC.

Our team of experts has professionally fulfilled every request: from the

initial meetings regarding the concept of the van, through concrete details

concerning the technical characteristics, choice of equipment and requests for

interior design, to the delivery itself and the subsequent support during field work.

The van was equipped with 5 digital cameras, 3 digital recorders, 24-channel audio

DSNG VAN

The mobile DSNG Van is equipped with 400 W TWT of Xycom and

Tandberg E5500 encoder in 1+1 mode along with upconvertors / downconvertors of

ADVENT and base band equipments. The DSNG van can be operated in both C or

Ku band and it has the unique dual band waveguide in it. The system is operational

since November 2002 The 2 meter antenna system is of advent make having the auto

tracking facility controlled through laptop computer and can track any satellite in

very short period automatically. It has a GPS system with flux gate compass etc used

for auto tracking of satellites. The vehicle

mounted DSNG Van supplied through BECIL is used in live coverage‘s for up

linking.

DETAILED DISCRIPTION

a) Studio center

The studio centre of Doordarshan has the following objectives.

1. To originate programs from studios either for live telecast or for recording

for a video tape.

2. To knit various other resources of program available at the production desk.

3. Processing/distribution of different sources to various distributions in

technical areas.

4. Routing of mixed program for recording/transmission via master switching

room and microwave to the transmitter or any other desired destination.

Activities in a television studio can be divided into three major areas such

as:

Action area.

CCU

Production Control Area.

Video Tape Recording.

b) Action area

This place requires large space as compared to any other technical

area. Action in their area includes stage, lighting, performance by artists

and arrangement to pickup picture and sound.

Requirement

1. Very efficient air conditioning.

2.Uniform and even flooring.

3. Acoustic treatment (use cyclorama on the walls of the action area).

4.Supporting facilities (like make-up room, wardrobe etc).

5.Communication facilities for the floor.

6.Audio and video monitoring facilities.

7.Cyclorama and certain tracks blue and black curtain for chroma keying

and limbo lighting respectively.

Fig PLAN OF TELEVISION STUDIO BHOPAL –

c) Camera control unit (CCU)

This is the camera control unit. This provides necessary adjustments of the camera

such as monitoring, super positioning of tubes (RGB picture tube in camera k-

125). Sequential display of picture tubes to find fault, tally light, color blanking,

cap of lens, chroma adjustment, color temperature adjustment, gain of light, view

find, filtering, menu section, auto facility.

d) Production Control Area

Activities:-

1. Direction to the production crew by the producer of the program.

2. Timing a production/telecast.

3. Editing of different sources available at the production desk.

4. Monitoring of output/off air signal.

5. Remote control for video mixer and library store and special effect.

6. Communicaton facilities with technical areas and studio floor.

The Production Control Area consists of:

1. Vision mixer

2. Character generator

3. Sync pulse generator

4. Sound and mixing control

5. Audio facilities

Vision mixer or video switching:

Through the video switching is done by the VM at the remote channel the

electronics is located in CAR. The vision mixer is typically a 16x1 or 24x1 cross

bar switcher relation any of the 10 or 20 input sources to 6 to 10 different output

lines. The input sources includes cameras, VTR, telecine cast signal etc.

Same coincident with the station sync are called synchronous while others

having their own independent synchronous are called non synchronous. The vision

mixer provides for the following operational facilities for editing of TV program.

1. Take or cut : Selection of any input source, switching clearly from

One source to another.

2. Dissolve : Fading out of no source of video and in another source

3. Superimposition : Keypad caption when selected in day is super imposed

of two sources on the background picture.

4. Special Effects : A choice of a no. of a wire patterns fell split screen as

Wipe effect.

The selected output can be monitored in the corresponding preview

monitor. All the picture sources are available on the monitors. The switches also

provided facilities to switch camera tally, light as an indication to cameraman

whether his/her camera is on or, out of the switch.

2. Character Generator

Character generator is provided to provide titles and credit captions during Roman

script. It provides high resolution characters for background edges etc. At present

bilingual and trilingual C.G. are also being used by doordarshan.

3. Sync. Pulse-Generator

It is essential that all the video sources and input to the switches are in

synchronism i.e. start and end of each time for all the frames of video sources is

concurrent. Their requirement is ensured by the sync. Pulse generator (SPG). SPG

consists of highly stable crystal electrically which forms clock for the generator of

video signal. These pulses are fed to all the video generally equipment to achieve

their objective of synchronism. It provides the following outputs:

1. Line drive

2. Field drive

3. Mixing blanking

4. Mixed sync.

4. Sound Mixing and Control

As a rule in television, sound accompanies the picture; several microphones

are generally required for production of complex television program besides other

audio sources also called married sound from telecine VTR and audio tape/disc.

Replays. All these audio sources are connected to the sound control console.

Fig- sound mixing

The sounds from different resources are controlled and mixed in accordance with

are requirement of the program split second accuracy is required for providing the

correct audio source in synchronization with the picture thus requiring lot of skill

from the engineer. Even the level of sound sometimes is varied in accordance with

the short composition called sound prospective.

5. Audio Facilities

An audio mixing console, with a number of inputs say about 32 inputs is

provided in a major studio. This includes special facilities such as equalization,

RFL, Phase reversal, echo send/receive and pre-filter digital reverberation units at

some placed takes records and EMI 938 disc reproduce are provided for playing

back/creating audio effects as independent resources to the switches.

e) Video Tape Recording

This unit provides the recording of the video as well as audio input. In other

words this unit records the video input and audio input coming from the production

control unit through VDA and ADA simultaneously in tape with the help of the

video cassette recording. The video tape recording system comprises of following

steps. For video input amplifier one output two pre-emphasis circuit. Driven

amplifier, FM-modulator, recording head amplifier, stepping brusher. Head drum.

Other output of video amplifier fed to sync separator and shape, servo-controlled

circuit, head drum motor drive, motor them motor fed to head drum. The four

video head for audio input fed to amplifier ultrasonic biasing network-amplifier

then to audio record head. A.C. bias oscillation is also used with ultrasonic biasing

network.

Fig- video transmission

For video input amplifier one output two pre-emphasis circuit. Driven

amplifier, FM-modulator, recording head amplifier, stepping brusher.

Head drum. Other output of video

amplifier fed to sync separator and shape, servo-controlled circuit, head

drum motor drive, motor them motor fed to head drum. The four video head for

audio input fed to amplifier ultrasonic biasing network-amplifier then to audio

record head. A.C. bias oscillation is also used with ultrasonic biasing network.

SLIP RING

BRUSHES

SWITCHER

AMPLIFIER

EQUALISER

AND

LIMITER

CIRCUIT

FM

DEMODULATO

R

VIDEO

AMPLIFIER

AM

MODULATO

R HEAD

DRUM

MOTOR

CAPSTAN

MOTOR CAPSTAN

MOTOR DRIVE

HEAD MOTOR

DRIVE SERVO

CONTROLLER

D CKT

AMPLIFIER

VIDEO

HEADS

SPEED CONTROL

SIGNALS

AUDIO HEAD

TO

MONITER

TO TV

RECEIVER

BLOCK DIAGRAM IN PLAYBACK MODE OF VIDEO TAPE RECORDER

Driven amplifier, FM-modulator, recording head amplifier, stepping brusher.

Head drum. Other output of video amplifier fed to sync separator and shape, servo-

controlled circuit, head drum motor drive, motor them motor fed to head drum.

The four video head for audio input fed to amplifier ultrasonic biasing

network-amplifier then to audio record head. A.C. bias oscillation is also used with

ultrasonic biasing network.

f) Control Apparatus Unit

This is the nerve center for a television station. Activities in this area

included.

1. Distribution of established power supply to different technical areas with

production devices.

2. Sync. Pulses generator and distribution.

3. Distribution of resources to various destinations.

4. Video processing and routing.

5. Electronics for camera chain, video switches special effect generator, test

signal and pattern generator.

6. Monitoring facilities

7. Patch panel for video and audio lines.

8. Electronics for micro wave links or other technical areas associated with

central apparatus room (CAR).

a. CCU b. Light control unit and dimmer room

c. ACR d. VTR

e. Telecine f. Digital library stage

g. Video graphic h. Post production and editing suit for

Outdoor work by the (ENG/EFP)

Post Production Room

This unit is made for editing purpose. Then unit edits the already

made program. This unit is also used for the audio recording such as to give

voice effect in the already made program.

Master Switching/ Control Room

Master switching or control room is used mainly for the local

transmission. This section sends signal to the earth station for the up-linking or

the signal. The unit also receive the Delhi Signal (FS) same as received by the

transmitter. And fed to transmitter to transmit the signal into air.

Studio Light

Light plays an important role in the studios and theatres. Artificial light not

only creates adequate filming or viewing conditions, but is also an important factor

in artistic direction. Many performance and light effects are not possible without

the correct lamps. Constantly, new light sources and equipment open up new

avenues lighting to meet the various requirements. There is a multitude of means

from the new luminaries‘ types (e.g. Footlights and softlights,flood and spots) to

special control and dimming equipment modern theatrelamps must satisfy all

demands on economy and lamp life as well as high requirements on luminous flux,

luminaries efficacy and color temperature. For their reason, we have developed a

whole range of progressive tungsten-halogen lamps and theatre lighting.

They combine the advantages of high grade quartz technology with the

superior technology of the tungsten-halogen cycle. Television shooting requires an

abundance of light. The ceiling of a modern studio is densely covered with flood

lights. Tungsten-halogen technology is responsible for more compact and mobile

luminaries which radiate less heat; our tungsten halogen lamps for films.

Television and theatre provide high luminous efficacy and lower power

consumption. They also yield a higher ratio of visible light infrared heat radiation.

The actors suffer less from the heat radiation. The actors suffer less from the heat

and the air conditioners are less loaded. For studio lightning therefore, the standard

color temperature for which electronic cameras and color films are balanced is

important.

Television Lighting

Technical requirements:

1. Incidental Lighting Level: In general it is governed by the sensitivity of

the camera tube, taking into account the working aperture of the camera

lens. The working lens operation is determined from the depth of field

consideration.

2. Contrast Ratio: Contrast is the ration between the luminance of the

lightest and darkest part of the subject or image. The scene contrast out-

of-door is the average 160:1, although it may be as 1000:1.

19

The uses of lighting to model a set i.e. create areas of light and shade

increase the overall contrast ratio.

3. Colour temperature: In colour television studios the colour temperature

of the light sources should be within 150K of the line upcolour

temperature i.e. 2950K to 2150K. 4. The working lens operation is determined from the depth of field

consideration. 5. Tungsten-halogen technology is responsible for more compact and

mobile luminaries which radiate less heat; our tungsten halogen lamps for

films. Television and theatre provide high luminous efficacy and lower

power consumption..

6. They also yield a higher ratio of visible light infrared heat radiation. The

actors suffer less from the heat radiation. The actors suffer less from the

heat and the air conditioners are less loaded. For studio lightning

therefore, the standard color temperature for which electronic cameras

and color films are balanced is important

Fig- lights used in studio

Artistic Requirements

1. Illusion of Depth: This is the first artistic consideration otherwise picture

will tend to look flat and uninspiring. Monochrome re-production takes

away the interest normally created by contrasting area of colour and it is

necessary to light for shape, form tonal contrast and surface texture. In

general, lighting can be divided in two parts, the first being modelling of

artists and second lighting the sets, subjects are modelled by lightusing

shadows.

2. Script: Script requirements have to be satisfied to create atmosphere and

mood whilst at the same time maintaining a balance picture content which

has a fairly constant main brightness, so minimising the effect at the receiver

due to the absence of D. C. restoration. Additionally, it reduces the amount

of vision control required.

The script requirement of basically twofold:-

Explicit - Day, light, interior, exterior.

Implicit - mood or artistic impression etc visualized by director

and lighting supervisor.

3. Compatibility: Not all domestic receiver are colour and a further

constraint is added to the transmitted picture, namely that the compatible

picture(monochrome) is not degraded. To artist the realization team

(lighting, scenic design, costume and make up) in this respect, most of the

studio control room monitors are monochrome. Only the monitors are used

for final assessment are colour.

4. Light Sources : The lighting sources fall into two categories-

Hard source : A hard source behaves as a point source and cast a

Single hand edge shadow.

Soft source : A soft source behave as a large area source taking

Into account the relative sides of objects and light

Source and the distance separating them.

5. Lighting Control: In a television production each scene will required it

own lighting plot with the appropriate dumiraires switched on and their

intensities balanced to give the desired effect. The intensities are varied by

some form of dimming arrangement, and the dimming and on/off are

remotely controlled by a channel controller on a lighting console.

6. Basic Portraiture : In portrait lighting, four basic lamp are used:

Key light: This is the principle resource of illumination. It gives

Shapes and modelling by casting shadows. It is the sun

In the sky, there should only be one sun. Normally it is

The hard source.

Filler: Controls lightly contrast by filling in shadows. It can

also provide catch lights in eyes. Normally a soft source.

Background light : Separates the person from the background,

Reveals back ground interest and shape.

Normally it is a hard source.

CAMERA

Introduction

A typical video camera consists of the following Sections.

1. Lens

2. Optical Block

3. Transducer or Pick-up device.

4. Electronic.

The lens and optical block forms camera optics.

The purpose of the camera lens is to focus the image at the face plate of a

pickup device i. e. to term a optical image. The lens used for the video camera

depends on the size of the pick-up device.

The lens for a video camera has the following section.

Back focus section with adjustment facilities for back focus and micro focus.

Focus section.

Zoom section with manual or servo mode.

Aperture section with manual or auto mode.

Servo drive assembly for zoom and iris control.

Whereas the optical assembly inside camera head has colour filters wheel,

optical block consisting of diachronic mirror, bias light and a suitable lens

mount.

CCD Device

Charge coupled devices are being used in studio cameras of full broadcast quality.

CCD device is a kind of transducer which converts optical image into electrical

signal. Any camera having CCD device is called a CCD camera.

Principle of CCD camera

Any camera will need a device to convert optical image into electrical

signal. For more sharpness or better resolution, we have to increase the elements of

small picture. This picture frame can now be focused on a structure of so many

CCD elements. Each CCD elements will now convert light information on it to a

charge signal. There should be arrangement to collect this charge and convert it to

voltage.

Types of CCD chips used as pick-up devices for CCD cameras are-

Interline transfer type

Frame transfer type

Frame interlining transfer type

Fig- cameras

T.V. Camera

A T.V. camera consists of three sections

1. A camera lens and optics: To form optical image on the face

plate if a pick –up device.

2. A transducer or pick-up device: To convert the optical image into an

electrical signal.

3. Electronic: To process output if a transducer to get a CCVS signals.

Fig- tv cameras

BLOCK DIAGRAM

Studio Camera KCM-125

KCM-125 color camera uses a 3-tube RGB system with plumb icon pick-up

tubes. The color camera head, thecamera control unit are each equipped with a

micro-computers are inter connected via several data lines and are in contact with

each other. Each micro-computer has its own program. When the camera is turned

on micro-computer can recall setup data which had been stored automatically when

the system was turned off.

The control Panel consists of the following set-up:

Set-up Add on unit.

Remote Control unit.

Camera Control unit.

Joystick panel.

Telecine

Telecine is an equipment to convert film based program material to a video tape,

optical image produced by the film projection is converted into a line scanner. A

typical side telecine room will have two no. of CCD telecine chain type FDL-60

two no. of sepmag sound following slide projectors compromising a camera

multiplex assignment switcher and monitors etc. in a studio setup besides side

scanners film editing tables and projectors FDL-60 can handle 16mm, 35mm

normal/cinema scope uses any type of sound.

EARTH STATION

Earth station in Bhopal doordanshan was meant for up-link M. P. Signal

services. It consists of expanded C-band up-link satellite system operating in the

frequency range 6.725GHz to 7. 025GHz for transmit and 4.5GHz to 4.8GHz for

receiving signals. The total system consists of 7. 0m parabolic reflector antenna

step track control system redundant LNA systems, redundant 3KW klystron high

power amplifier redundant up convertor with change of the earth station

equipment, redundant 70MHz. video modulator and demodulator video and audio

processing units, control remote, power distribution panel, dehydrator micro-

wave handwave and set of measuring instruments.

Up-Link

Video Hum Suppressor

Hum Suppressor is intended to be used in television network for reducing the

spurious signal which arise as a result of different earth potentiality the sending

and receiving ends of a transmission line. It is effective in suppressing spurious

signal.

Video Equalizer

The video equalizer is used to compensate for the video signal attenuation in cables

of length up to 300m. The equalization can be adjusted in 20 steps. The outputs are

free from mutual interaction and from the input..The equalizer is suitable for color

television as different phase distortion is very small.

Video Distributer

The video distributer amplifiers are employed to distribute blank

video (BA) signals to a no. of units. Video distributer contains two independent

distributing amplifiers each provides 5 outputs.

FIG- Video Distributer

Stab

The color stabilizing amplifier is used along with a sync processor to process

the composite video signal. The composite video

signal is processed to remove the hum and noise for the timing component in the

sync processor which produces regenerated noise free sync and blanking signal.

These noise free sync and blanking signals are added to the composite color video

signal in the color stability amplifier.

Modulator

The modulator subsystem frequency modulates both video and up to two

audio signals to IF (70MHz.)

Video/Sound combiner

The video/sound combiner accepts video input from the 5MHz low pass

filter module, sound subcarrier signals from the sound modulator. Modules 1 and

2 and 25MHz energy dispersal signal from the ED generator module combines and

amplifiers them to give up a composite output.

Up-Convertor

The up –converter frequency translating circuits which convert 70MHz

signal to FC is in the band 5.8GHz to 6.425GHz (6.725-7.025for external C-band).

The up-convertor has a nominal gain of 15 dB with the nominal power being

0dBm. The up-converter contents filters for super vision of Lo Leak and spurious

products. Equalizers compensate for group delay introduced by the filters and

beep amplitude response within specification.

High Power Amplifier

The klystron amplifier contains a high power klystron amplifier tube solid

state amplifier IPA, various RF components. Beam power supply, beam power

regulator supply and a control panel which controls the entire system.

DOWN LINK

LNA (Low noise amplifier)

Low noise bi-polar transistors are used as an active device in these

amplifiers, LNA provides again in excess to these incoming signals. This gain also

ensures that the noise figure of succeeding stages does not degrade over all noise

figure of the system.

The micro skip band pass filter follows the LNA ensure image rejection. The

input- output impedances of this circuit block are 50 ohms.

Down Converter

The down converter constants frequency translating circuits which convert

FC MHz input signal to70MHz signal where FC is in the band of 3625MHz to

4200MHz (4500MHz to 4800MHz for external c band). The down converter has

variable gave of 58dB to 8dB, with nominal power output being -12dBm. The

down convertor contains filter for suppressions of local oscillators (LO) leak and is

various products. Equalizer compensate for group delay introduced by filters and

keep amplitude response within specification.

Demodulator

The demodulator system frequency demodulates both video and up to two

audio signal to IF (70MHz).

Working

Video drives are routed through the hum suppressor forelements hum and

then video equalizer studio lines are routed through stab, where different video

parameters viz. chrommance level, luminance level, blanking level, sync. , level

and color burst level adjusted. Then finally processed video signal feed to

modulator input. After switching audio signal passed through a limiting amplifier

where audio level limits to a preset wall and pre-emphasis is done (boosting of

higher frequency). Then audio signal goes to input of the modulator

AIR CONDITION

One of the primary function of an air conditioning system is to maintain

conditions that are conductive the code of minimum requirement for comfort air

conditioning sponsored by a a-ahvfasvf has defined the scope of system and its

state comfort air conditioning .for purpose of the code is defined as the process by

which simultaneously the temperature moisture contain movement and quality of

air in enclosed spaces, intended for human occupancy may be in within required

limits

In order to satisfy the stipulated requirement as complete air conditioning

system is obliged to perform the following function.

1. Cooling and dehumidification for summer condition

2. Heating and humidification for winter conditions

3. Air filtration and proper ventilation the year along

Necessarily, these function involve control of temperature

humidity, purity and movement of air .mechanical refrigeration is achieved by

altering compressing and expanding the refrigerant with the help of a compressor

and pressure reducing device

Compressors Serve Two Purposes:

1 it draws the refrigerant from the chiller and forces it into the condenser

2 it increases the pressure of the refrigerant

By sucking the refrigerant, the compressor reduces the pressure in the

cooling coil and maintains it at level low enough to permit the refrigerant to boil

or vaporized and consequently heat in the process. By discharging refrigerant

vapour into the condenser the compressor increase vapour pressure and

temperature. The hot vapors flow to the condenser where it is condensed into the

liquid at high temperature giving up heat to atmospheric Air or water depending

upon the weather the condenser is air cooled or water cooled. The liquid refrigerant

thus passes through pressure reducing devices such as expansion Valve.

BOLCK DIAGRAM

Fig-BLOCK DIAGRAM OF AIR CONDITIONING UNIT

Primary function of an air conditioning system is to maintain conditions that

are conductive the code of minimum requirement for comfort air conditioning

sponsored by a a-ahvfasvf has defined the scope of system and its state comfort air

conditioning .for purpose of the code is defined as the process by which

simultaneously the temperature moisture contain movement and quality of air in

enclosed spaces

USEFULNESS

Energy consumption

Artificial lighting consumes a significant part of all electrical energy

consumed worldwide. In homes and offices from 20 to 50 percent of total energy

consumed is due to lighting. Most importantly, for some buildings over 90 percent

of lighting energy consumed can be an unnecessary expense through over-

illumination. The cost of that lighting can be substantial. A single 100 W light bulb

used just 6 hours a day can cost over $25 per year to use (.12/kWh). According to

the UN Environment Programme/Global Environment Facility en.lighten initiative,

by simply replacing all incandescent lamps with energy efficient compact

fluorescent lamps globally, 409 TWh per year would be saved, which is

approximately 2.5% of global electricity consumption. This is equivalent to the

combined yearly electricity consumption of the United Kingdom and Denmark.[1].

Thus lighting represents a critical component of energy use today, especially in

large office buildings where there are many alternatives for energy usage in

lighting. There are several strategies available to minimize energy requirements in

any building:

Specification of illumination requirements for each given use area.

Analysis of lighting quality to ensure that adverse components of lighting (for

example, glare or incorrect color spectrum) are not biasing the design.

Integration of space planning and interior architecture (including choice of

interior surfaces and room geometries) to lighting design.

Design of time of day use that does not expend unnecessary energy.

Selection of fixture and lamp types that reflect best available technology

for energy conservation.

Training of building occupants to use lighting equipment in most efficient

manner.

Maintenance of lighting systems to minimize energy wastage.

Use of natural light - some big box stores are being built (ca 2006 on) with

numerous plastic bubble skylights, in many cases completely obviating the

need for interior artificial lighting for many hours of the day

Load shedding can help reduce the power requested by individuals to the main

power supply. Load shedding can be done on an individual level, at a building

level, or even at a regional level.

Specification of illumination requirements is the basic concept of deciding

how much illumination is required for a given task. Clearly, much less light is

required to illuminate a hallway or bathroom compared to that needed for a word

processing work station. Generally speaking, the energy expended is proportional

to the design illumination level. For example, a lighting level of 80 footcandles

might be chosen for a work environment involving meeting rooms and

conferences, whereas a level of 40 footcandles could be selected for building

hallways. If the hallway standard simply emulates the conference room needs, then

twice the amount of energy will be consumed as is needed for hallways.

Unfortunately, most of the lighting standards even today have been specified by

industrial groups who manufacture and sell lighting, so that a historical

commercial bias exists in designing most building lighting, especially for office

and industrial settings.

Daylighting

Daylighting is the oldest method of interior lighting. Daylighting is simply

designing a space to use as much natural light as possible. This decreases energy

consumption and costs, and requires less heating and cooling from the building.

Daylighting has also been proven to have positive effects on patients in hospitals as

well as work and school performance. Due to a lack of information that indicate

the likely energy savings, day lighting schemes are not yet popular among most

buildings..

Portable air condition

A portable air conditioner is one on wheels that can be easily transported

inside a home or office. They are currently available with capacities of about

5,000–60,000 BTU/h (1,800–18,000 W output) and with and without electric-

resistance heaters. Portable air conditioners are either evaporative or refrigerative.

Portable refrigerative air conditioners come in two forms, split and hose.

These compressor-based refrigerant systems are air-cooled, meaning they use air to

exchange heat, in the same way as a car or typical household air conditioner does.

Such a system dehumidifies the air as it cools it. It collects water condensed from

the cooled air and produces hot air which must be vented outside the cooled area;

doing so transfers heat from the air in the cooled area to the outside air.

A portable split system has an indoor unit on wheels connected to an outdoor

unit via flexible pipes, similar to a permanently fixed installed unit.

Hose systems, which can be monoblock or air-to-air, are vented to the

outside via air ducts. The monoblock type collects the water in a bucket or tray

and stops when full. The air-to-air type re-evaporates the water and discharges it

through the ducted hose and can run continuously.

A single-duct unit uses air from within the room to cool its condenser, and

then vents it outside. This air is replaced by hot air from outside or other rooms,

thus reducing the unit's effectiveness. Modern units might have a coefficient of

performance (COP, sometimes called "efficiency") of approximately 3 (i.e., 1 kW

of electricity will produce 3 kW of cooling). A dual-duct unit draws air to cool its

condenser from outside instead of from inside the room, and thus is more effective

than most single-duct units.

Health issues

Air-conditioning systems can promote the growth and spread of

microorganisms, such as Legionella pneumophila, the infectious agent responsible

for Legionnaire' disease, or thermophilic actinomycetes; however, this is only

prevalent in poorly-maintained water cooling towers. As long as the cooling tower

is kept clean (usually by means of a chlorine treatment), these health hazards can

be avoided.

Energy use

In a thermodynamically closed system, any power dissipated into the system

that is being maintained at a set temperature (which is a standard mode of

operation for modern air conditioners) requires that the rate of energy removal by

the air conditioner increase. This increase has the effect that, for each unit of

energy input into the system (say to power a light bulb in the closed system), the

air conditioner removes that energy.[14]

In order to do so, the air conditioner must

increase its power consumption by the inverse of its "efficiency" (coefficient of

performance) times the amount of power dissipated into the system. As an

example, assume that inside the closed system a 100 W heating element is

activated, and the air conditioner has an coefficient of performance of 200%. The

air conditioner's power consumption will increase by 50 W to compensate for this,

thus making the 100 W heating element cost a total of 150 W of power.

Humidity control Refrigeration air-conditioning equipment usually reduces the

absolute humidity of the air processed by the system. The relatively cold (below

the dewpoint) evaporator coil condenses water vapor from the processed air (much

like an ice-cold drink will condense water on the outside of a glass), sending the

water to a drain and removing water vapor from the cooled space and lowering the

relative humidity in the room. Since humans perspire to provide natural cooling by

the evaporation of perspiration from the skin, drier air (up to a point) improves the

comfort provided. The comfort air conditioner is designed to create a 40% to 60%

relative humidity in the occupied space. In food-retailing establishments, large

open chiller cabinets act as highly effective air dehumidifying units

SUMMARY

TECHNICAL FACILITY

Doordarshan Bhopal was commissioned on 20th October 1992. There are two

Studios – A of an area of 374 Sq.m. and Continuity Booth (Studio-B) of an area of 50

Sq.m. two Transmitters (DD-I & DD-News) of 10 KW each, one Earth Station

Unlinking the Regional Service of M.P., one OB Van for outdoor live coverage‘s and

one DSNG Van for Mobile unlinking.

STUDIO-A

Studio-A having an area of 374 initially equipped with 4 nos. of A Philips

Digital LDK 20 and LDK 100 (two each) CCD cameras and modern lighting

equipments with dimmer controls. There are 14 nos. of motorized buttons with

provision for 8 light fittings in each button and 36 nos. of motorized buttons with

provision for 4 light fittings in each buttons. There are also 18 nos. of telescopic light

fitting arrangements in the Studio floor. This studio is mainly used for programme

recordings. Presently 31 nos. of cool lights are in use.

PRODUCTION CONTROL ROOM (PCR-A)

PCR is equipped with 16 input versatile vision mixer of PDS 9000 Digital

Switcher with various special effects and 16 channel sound craft audio mixer with the

facility of individual channel equalization, limiting and Phone-in console. One

reverberation unit & one Advance Feedback Suppressor (dBX) for producing special

audio effect is available in PCR. In addition to the above, one Computerized MOVE-

CG for supering titles and other special effects is also installed in PCR . The PCR-A is

also equipped with Dimmer Control panel for Studio-A.

CAMERA CONTROL UNIT (CCU)

In this section, the studio levels are adjusted and controlled for proper

matching in order to achieve excellent quality recording, now integrated in PCR

console itself.

VIDEO TAPE RECORDER (VTR)

VTR is equipped with 4 nos. of BETA format and one no. of DVC Pro AJD

VCRs of broadcast quality (PVW 2800-4 nos). These are used for studio recordings

and transmissions. It is also equipped with Video Server make Letch VR445

consisting of two independent recorders and players based on hard disc recording

system.

MASTER SWITCHING ROOM (MSR)

This section is equipped with a 16X16 Digital Routing Switcher where all the

signals from Studio-A, Studio-B, Transmitter, Earth Station, OB Van signal, DSNG

etc are routed to various areas as per requirements for recording/transmission. One

OFC link between MSR and Earth Station has also been installed.

POST PRODUCTION FACILITY

There is a separate post production section having 3 nos. of edit suites with

voice over facility, each edit suite having following component of the equipment.

Suit-1[A/B Roll edit suit with DVE cum Video switcher]

VM (Snell & Wilcox), Edit Controller AJ 850, Audio mixer (12 Channel),

CD Player, Phone in console, move CG 2001, DVC pro AJ-D455E, PVW-

2800P, PVW-2800P

Suit-2 [Beta Edit Suit with FXE-120P]

FXE-120P, PVW-2800P, DVC Pro AJ-D455E, BVW-70P

Computerized editing system is also available at this Centre having the latest state of

the art technology used for editing/post production for better presentation of the

programmes namely, NLE, Media 100,DPS Velocity, QUATTRUS NLE, 3D Graphics

& ISLEWIZ Compuer graphics.

STUDIO-B

Studio-B (Continuity booth) having an area of 50 sq.m was initially equipped

with three KCA-110 tube cameras and now replaced with two CCD cameras (SONY

DXC-50-1 No. KYD-29JVC-1 no) & modern lighting equipments with 7 nos. of cool

lights mounted on fixed grid . One auto BDL system has been integrated with SONY

DXC-50 Camera and another unit has been networked with News Room for semi

automation of News system. This Studio is used for transmission of Regional Service

including Regional News.

PCR-B

PCR-B is equipped with 16 input versatile vision mixer of PDS 9000 Pinnacle

make with various special effects. 16 channel Sound Craft make audio mixer with

facility of individual channel equalization and limiting. In addition to the above, one

computerized MOVE CG for supering titles, Phone-in-Console, Advance feedback

Suppressor and other high quality bi-lingual Collage make CG is also installed in

PCR-B.

ENG

This section is equipped with 6 nos. of Beta camcorder unit, 6 nos. of DVC Pro

camcorder and 3 no of Mini DV Camcorders for field coverage. These units are

deployed throughout M.P. for recording all important and special events which are

later edited and including in the news/programmes. Four No of DVCPRO50

Camcorders are being included.

A/C PLANT

The Studio is air-conditioned with 4X60 tones centrally air-conditioned plant

with 5 nos. of air handling unit of M/s Utility make. In addition to that, there are 4 nos.

of package units of Blue Star make for other sections.

POWER SUPPLY

Two 33 KVA Feeder are terminated at DDK complex from which power supply

is extended to studio complex, transmitter and Earth Station. In addition to above,

captive power supply is available for meeting the emergency requirement of Studio,

Transmitter and Earth Station. Diesel Generator having capacity of 62.5 KVA each is

used at Studio, DD-I, DD News Transmitter, Earth Station and 35 KVA D.G is used

for OB Van set up. There is a 40 KVA online UPS system with back up period of 30

minutes for all Studio equipments and 20 KVA UPS for OB Van in order to maintain

uninterrupted transmission.

CLIPMAIL SYSTEM

Doordarshan Kendra, Bhopal has installed a Clip mail Receive system through

which video clips from different of Doordarshan i.e. Indore, Gwalior, Jabalpur, Rewa

and Sagar can be received. The Transmit unit has been installed at the above Kendras.

EARTH STATION

Earth Station Bhopal was commissioned on 19/11/93 and DDK, Bhopal is up

linking M.P. Regional Service. Earth Station is equipped with two number of 3 KW

High Power Amplifier of MCL make upgraded with 2+1 Digital Simulcast facility,

Recently two amplifiers of 400W have included. There is a 7 meter solid motorized

PDA having linearly polarized feed with auto tracking facility.

TRANSMITTER-DD-I

Bhopal was brought on map of Doordarshan with the commissioning of a Low Power

Transmitter for relay of National Programmes on 19th November, 1982. This was

upgraded to a 10 KW High Power Transmitter operating in Channel-5 radiating DD-I

programmes. It is a BEL Mark-II Transmitter working since 24th October, 1984. This

transmitter has further been replaced by NEC Transmitter on dated 28/12/2003.

TRANSMITTER-DD-II (NEWS)

Metro channel transmission was started on 30th July 1994 with commissioning

of Low Power Transmitter. This has been upgraded to a 10 KW High Power

Transmitter operating in CH #7 radiating DD-II Metro programmes. It is a Thomcast

Transmitter commissioned on 3/8/2000 and dedicated on 12/5/2001. It is a solid state

transmitter with the latest state of the art technology.

Both DD-I and DD-II Transmitter outputs are combined and signal radiated

with a signal Wide Band Antenna system of Jampro, USA make, which has been

installed on 11/7/2001.

The Central Air Conditioning Plant For TV Studio Bhopal

Capacity 4x60 T.R

Refrigerant Freon 22

Type of System Chilled Water Type.

Oil Servo Freeze F-68.

S.NO Equipments Make type-Model Capacity (Each)

1 Compressor Utility trane 3E-5H-60 60TR

2 Compressor-Motor 4BD SPDP 75HP

3 Condenser Utility trane CDS-322 100TR.

4 Chiller Utility trane EVP-368 60TR

5 Cooling Tower Prajapati

induced Draft

type 120TR.

6

Condenser Water

Pump Kirloskar FRP

7

Chilled

WaterPump Kirloskar KDS-830 7.5 HP

8

Water Softening

Plant NIMA

6000 LTS

9 Make UP Water Sintex

10000 LTS

10 Make UP Water Kirloskar

2HP

11 Air-Handling Unit Utility trane

12 A-H-5 Utility trane

AH-5

13 A.H-7 Utility trane Built up AH-7

14 A.H-7 Utility trane

AH-7

15 AH-9 Utility trane

AH-9

CONCLUSION

The technology of earth stations has been reviewed and a few illustrative

systems have been described. In coming years the number of large earth station

facilities that we are accustomed to seeing will continue to grow. However, in

addition, there will be an exponential growth of small earth terminals for consumer

services. Like a web, the major nodes will be filled in by a dense network of

smaller nodes of varies types and sizes.

An earth station, ground station, or earth terminal is a terrestrial terminal

station designed for extraplanetary telecommunication with spacecraft, and/or

reception of radio waves from an astronomical radio source. Earth stations are

located either on the surface of the Earth, or within Earth's 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 an earth station successfully transmits radio waves to a spacecraft (or vice

versa), it establishes a telecommunications link.

Earth stations may occupy either a fixed or itinerant position. Article 1 III of

the ITU Radio Regulations describes various types of earth stations, stationary and

mobile, and their interrelationships.

Specialized satellite earth stations are used to telecommunicate with

satellites—chiefly communications satellites. Other earth stations communicate

with manned space stations or unmanned space probes. An earth 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 an earth station's line of sight, the earth station is

said to have a view of the satellite. It is possible for a satellite to communicate with

more than one earth station at a time. A pair of earth stations are said to have a

satellite in mutual view when the stations share simultaneous, unobstructed, line-

of-sight contact with the satellite.