my training report (pdf)
TRANSCRIPT
A
SUMMER TRAINING REPORT
ON
BROADCASTING & STUDIO SETUP
IN
“DOORDARSHAN KENDRA”
(JAIPUR)
Submitted for partial fulfilment for the award of the degree of the
Bachelor Of Technology
Rajasthan Technical University, Kota
(2014-2015)
SUBMITTED TO: SUBMITTED BY:
Mr. Mukesh Arora Prakhar Gupta
Reader, ECE branch BTECH, 4th year (7SEM), ECE
Department of Electronics and Communication Engineering
SWAMI KESHVANAND INSTITUTE OF TECHNOLOGY
MANAGEMENT & GRAMOTHAN, JAGATPURA
JAIPUR
ACKNOWLEDGEMENT
Training is one of the important aspects for an engineering student’s carrier. It is
basically to strengthen the practical concepts. During this training student gets
aquainted with the latest technology and recent development.
Firstly, I convey my sincere thanks to all the employees of DDK, JAIPUR. Their love
and guidance are omnipotent and incompatible throughout the training period. I convey
special thanks to A.K.Tambi for providing me the opportunity to undergo this training
and I also express thanks to all hard members for their help and co operation.
I also want to thank to Mr.Mukesh Arora (Reader,EC) for allowing me to do my
summer training from DDK jaipur.
- Prakhar Gupta
i
TABLE OF CONTENT
CHAPTER NO. TOPIC PAGE NO.
CERTIFICATE i
ACKNOWELEDGEMENT ii
LIST OF CONTENTS iii-v
LIST OF FIGURES vi-vii
CHAPTER 1 INTRODUCTION TO BROADCASTING 1
1.1 Organizational setup 3
1.2 Technical details 4
CHAPTER 2 STUDIO 4
2.1 Main job in studio 4
2.2 Equipments in studio 5
2.3 Equipments in PCR 5
2.4 Equipments in MSR 6
2.5 Equipments in VTR 6
2.6 News section 6
2.7 OB van 7
2.8 DSNG van 7
ii
CHAPTER 3 Television camera 7
3.1 Live camera 8
3.2 CCD sensor 9
CHAPTER 4 Video production switcher & digital video effect 12
4.1 Basic function of switcher 14
4.1.1 Method of transitions 14
4.1.2 Mixing 15
4.1.3 Wiping 16
4.1.4 Keying 16
4.2 Key terms 19
4.2.1 Chroma keying 19
4.3 Configuration of production switcher 19
4.4 Digital video effect 21
CHAPTER 5 Satellite communication 24
CHAPTER 6 Microwave link, optical fibre link & measurement 25
6.1 Links for OB coverage system 25-26
6.2 Wave propagation 26
6.3 Antennas 27-30
iii
CONCLUSION viii
REFERENCE ix
iv
LIST OF FIGURES
Figure No. Figure Description Page No.
1.1 Organizational setup 3
2.1 Studio setup 4
2.2 Equipments in PCR 5
2.3 Block diagram of News section 6
2.4 Block diagram of OB van 7
2.5 Block diagram of DSNG van 7
3.1 Graph of knee function 10
3.2 Graph of Gamma & gamma correction 11
3.3 Transfer function 12
4.1 Vision mixer 13
4.2 Keying 17
4.3 Key filling 18
4.4 Chroma keying 19
4.5 Light effects 23
5.1 Satellite communication 24
6.1 Simplified microwave link 27
v
6.2 Microwave transmitter link 28
6.3 Microwave receiver link 29
6.4 Down converter 30
1
1. Introduction
What is broadcasting?
The process of sending information to a distant place is called broadcasting. It is a one
way communication with interaction. We can send an information to distant place
with good quality of intelligence/signal.
Doordarshan aims to provide information, education and entertainment for the public.
History of broadcast
Pre-independence
June, 1923
Broadcast of programmes by the radio club of Bombay.
November, 1923
Calcutta radio club puts out programmes.
16th may, 1924
Madras presidency radio club founded.
31st July, 1924
Broadcasting service initiated by the club.
23rd July, 1927
Indian broadcasting company (IBC), Bombay station inaugurated by Lord Irwin--The
Viceroy of India.
26th August, 1927
Calcutta station of IBC inaugurated.
1st April, 1930
Indian state broadcasting service under department of industries and labor commences
on experimental basis.
2
March, 1935
Controller of broadcasts constituted a new department.
August 30, 1935
Controller of broadcasting in Lionel Fielden appointed the first India.
1st April, 1930
Indian state broadcasting service under department of industries and labour
commences on experimental basis.
March, 1935
A new department controller of broadcasts constituted.
August 30, 1935
Lionel Fielden appointed the first controller of broadcasting in India.
June 8, 1936
Indian state broadcasting service becomes all India radio and in the same year Delhi
station was formed.
November, 1937
Air comes under department of communication.
1st October, 1939
External services started with push to broadcast.
October 24, 1941
AIR comes under department of I & B.
23rd February, 1946
AIR comes under the department of information and arts.
3
Facts as on 15th august 1947
When India attained Independence in 1947, AIR had a network of six stations and a
complement of 18 transmitters. The coverage was 2.5% of the area and just 11% of
the population. Rapid expansion of the network took place post-independence.
On 12th November 1947 the voice of Mahatma Gandhi was broadcast in air and since
then it is celebrated as broadcasting day. Television (Doordarshan) started in India in
the year 1959 with black and white transmission. The black & white converted fully
into color in 1982 during asian games.
1.1 ORGANIZATIONAL SETUP
Figure 1.1: Organizational Setup
An overview of DDK Jaipur
• Started in 1977 as UDK
• Studios came in 1987
• 24x7 launched on 16th aug-13
MINISTRY OFI & B
PRASAR BHARTI
AKASHVANI
PROGRAMME NEWS ENGINEERING
DOORDARSHAN
PROGRAMME ENGINEERINGNEWS
4
1.2 Technical details
STUDIO:
• Recording studio-400sqm
• Transmission studio-50sqm
• 7 camera OB van
• Ku band DSNG van/digital e/s
2. STUDIO SETUP
Figure 2.1: Studio setup
2.1 Main jobs in studio
• Program Production.
• Post Production.
Studio IFloor PCR I
MSR
VTR
EXTERNALSIGNALS
Earth STATION
TRANSMITTER
Studio IIFloor
PCR II
OFC
STL
From ENPS
PS AC
5
• Transmission
2.2 Equipments in studio
• Program Sets
• Lights
• Cameras
• Microphones
• Communication
2.3 Equipments in PCR
• Production panel
• CCU
• Vision mixer
• Audio console
• Lighting panel
• Communication
Figure 2.2: Equipments in PCR
6
2.4 Equipments in MSR
• Cameras hardware
• Vision Mixer hardware
• Sync Pulse generator
• Video/Audio distributors
• S.T.L transmission unit
• OFC transmission unit
• IRD’s
2.5 Equipments in VTR
• video recording machines
• servers
2.6 News section
FIG 2.3 News section
7
2.7 OB Van
It is a Multi camera setup used for big recordings/live coverage’s
Figure 2.4: OB van
2.8 DSNG Van
Digital satellite news gathering van employed for news coverage's. It has an up
linking system to uplink the signal to the satellite
Figure: 2.5 DSNG van
3. Television camera
3.1 Live cameras
Studio Camera
OB camera
ENG camera
Live camera generates video signals from the optical images of indoor and outdoor
scenes, which may be under the controlled conditions of a studio (Studio camera), a
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sport venue (OB camera), or at any location in the field, such as news event, or in the
home (ENG camera)
Studio cameras are designed to provide optimum performance in a controlled indoor
environment, usually at the expense of size, weight, and portability. These cameras
have all the features necessary to operate in a system with other cameras and
recorders. The basic functions of portable and studio cameras are similar, but the
portable camera must have the ability to control its own operating parameters such as
gain and sensitivity control automatically, because the camera user cannot be required
to make any technical adjustments
Studio Cameras
studio cameras are larger and locating some of the equipments remote from the
camera head
A larger camera is mechanically more stable and, with the proper mounting
equipments, it can be moved more smoothly than a small light weight camera.
A larger camera can support larger lenses which provide faster optical speed and
greater zoom ranges. This is especially important for sporting event pickup
Studio cameras are always connected into a system, which requires a large
number of connections to support synchronization, video and audio going both
from and to the camera, control, intercom and power. Now a day’s studio cameras
generally use atria cable, with all signals multiplexed on it.
In studio setting. It is desirable for the camera operator to devote all his or her
matters or adjustments should be handled elsewhere. Thus studio cameras usually
have a remote control position where a technically skilled operator can oversee the
camera’s technical operations, and do whatever is required to optimize the picture
performance and quality
A TV camera consists of three sections
A Camera lens and optics: To form optical image on the face plate of a pickup
device. A transducer or pick up device: To convert optical image into an electrical
signal.
Electronics: To process output of a transducer to get a CCVS signal.
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3.2 CCD sensor
A CCD sensor is a pixel sized solid state photosensitive element that generates and
stores an electric charge when it is illuminated. It is a building block for a CCD
imager, which is a rectangular array of sensors upon which an image of the scene is
focused. In most configurations, the sensor includes the circuitry that stores and
transfers its charge to a shift register, which converts the spatial array of charges in
the CCD imager into a time- varying video output current.
Functions performed by CCDs:
1. Photo sensing
2. Sampling
3. Charge storage
4. Charge transfer
CCD imagers
CCD Imagers consists of a matrix of individual sensors, one sensor per image pixel
(three for tri color CCD), mounted in a rectangular array on a silicon substrate. They
develop electric charges that are proportional to their illumination by an image of the
scene focused on the array. The charges are stored temporarily in the potential “wells”
of the sensors and are transferred to shift registers during the field blanking interval,
which then transmit them to the imager output in the proper time sequence to generate
the video output signal. The purpose of CCD transfer process is to read out the pixels’
stored charges sequentially to a video output
Three different types of CCD chips are used as a pick up device for
cameras
1. Interline transfer type (IT)
2. Frame transfer type (FT)
3. Frame Interline transfer type (FIT)
4. Knee function (highlight control)
10
Highlight is name given to an area of the scene where the light level goes above
the level chosen for reference white. This can come from light bulbs, car
headlights at night, reflections, or simply a bright sky creeping into a scene that is
otherwise
Figure 3.1: Knee function
Gamma & gamma correction
In TV system the transfer function between light values and signal voltages at picture
tube is not linear. A receiver picture tube does not emit light in direct proportion to
the signal voltage applied. This nonlinear relationship between light output (L) and
signal voltage (V) may be expressed as
L (V) γ
The exponent of the transfer function is called gamma (). It can specify the slope of
the transfer curve at any point.to compensate for this non linearity at the picture tube,
an opposite distortion, referred to as Gamma correction is introduced at the picture
source. If E is the camera voltage resulting from a given light input (Li), then a
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gamma corrected voltage of (E) 1/ will yield a light output at the receiver which is
directly proportional to light input at camera.
LO (V) γ [(E) 1/] γ E Li
LO Li
Or Light output Light input at pickup device. (It is presumed that the camera
voltage E has been arranged linearly, related to the light input at the camera).
Gamma correction is usually applied in each of three color channel in our TV system.
If Gamma is less than unity (used in pickup devices), whites are compressed (crushed)
and blacks are expanded (stretched).If the system is linear the gamma of the system is
unity in black & white TV, effect of high overall gamma is to stretch the white and
compress the black, but in color TV, it causes serious errors in the hue.
A Gamma of more than unity (typically 1.2) is preferred to compensate for the loss of
contrast due to optical flare etc.
Figure: 3.2 Gamma & Gamma correction
The exponent of the transfer function is called Gamma. It can specify the slop of the
Curve at any point
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Transfer function of pick up device
Figure 3.3: Transfer function
4. Video production switcher and digital video effect
4.1 Vision mixer or production switcher
Television program. Production switchers are essential to all live operations.
Production switcher is used to either switch or cut between two video sources, or to
combine them in a variety of ways. The principal methods used to combine video are
Mixing, Wiping, & Keying.Vision mixer and video mixer are almost exclusively
European terms to describe both the equipment and operators.
In the United States, the common name for a device of this kind is (video) production
switcher and the common name for the operator of the device is known as technical
director
13
Figure 4.1: To show vision mixer
14
4.2 Basic functions of a switcher
Cut operation or switching between two sources.
Mixing or dissolve.
Wiping.
Keying.
4.2.1 Methods of transitions
Cut
Mix or dissolve
Wipe
Fad
DVE
Cut operation
It allows having changeover from one video source to another source
instantaneously. Switching between one sources to another is done during vertical
interval period to make the changeover invisible on the screen.
Type of mixing
Additive mixing
Non additive mixing
Additive mixing
15
Non additive mixing
4.2.2 Mixing
Mixing is an additive combination of two video sources. Two input sources are mixed
in proportion in a summing amplifier as decided by the position of the control fader.
Two extreme positions give either of the sources at output. Middle of the two fader
gives mixed output of the two sources. The sum of two video sources is always 1 volt
p-p. Control to the summing amplifier is derived from the fader.
16
4.2.3 Wiping
This is a non-additive combination of two sources. A switching occurs during the
active video at specific points on the raster to produces a pattern, between two video
sources. Switching is controlled by an internal wipe pattern generator which can
provide the waveform either saw tooth or parabola at H, V or both H and V rates. The
very simple to very complex waveform can be generated by the wipe pattern
generator. Simple patterns can be generated by logical combination of different
waveforms however the production of more complex patterns is better handled by a
microprocessor
4.2.4 Keying
This is also a non-additive combination of two video sources. In keying
operation, part of the picture (Background) is replaced by another picture
(foreground) according to the limits set by a third signal called key or alpha
signal which can be derived either from the picture itself being keyed (self- key
or internal key), or from a third video signal from camera or CG or DVE etc.
(Auto select or external key).
Keying signal provides a switching square waveform to switch between
foreground and background sources during active video. This keying signal can
be generated either by the luminance, hue or chrominance of the source input.
The keyed portion can be filled with the same source (self- key) or with the color
(Matt key) or external source (split key)
4.3 Key terms
4.3.1 Luminance key
4.3.2 Matt key
4.3.3 Self key
4.3.4 Split key
17
Figure 4.2: Keying
There are three elements to every key:
1. Background (from background bus).
2. Key cut (Key hole cutter made by any of the four types: Luminance, Linear,
Chrome, Preset pattern)
3. Key fill (From key fill bus or matt fill
18
Figure 4.3: Key filling
Rules for making key cuts:
Luminance key
Black or white off or on.
Cuts a hole where black meets white.
Key is either on or off.
Linear key
Chrome key
Cuts a hole from hue of a color.
Preset pattern key
19
Cuts a hole by using the black and white image from the wipe generator.
4.3.1 Chroma keying
Figure 4.4: Chroma keying
4.4 Configuration of production switcher
analog or digital
component or composite
number of inputs
number of m/e systems
m/e functions
mix
mix transition
wipe
20
Wipe Transition
Key
Main features
Mixing (Or Dissolve)
Manual or auto transition
Additive or non-additive mixing
Wiping
Number of patterns
Rotational patterns
Bordering mode, hard or soft, and color edges
Direction mode
Modulation mode
Positioner mode
Aspect change
Multiple patterns
Keying
Luminance, Linear, Chroma, and preset pattern key
Source selection
Invert mode
Insert selection (video, color or still stores)
Bordering selection (in title keys)
Key shadow features
21
Effects memory system
User programming
Learn mode programming
Additional switcher features
Separate mix system (PGM )
Title or downstream keying
Quad splitting
Tally systems
Auxiliary switching
Digital video effects
Custom control
4.5. Digital video effects
Digital video effects are created by digitizing the video effects signal so that it can be
stored, retrieved, and manipulated in digital format. These effects are generated by
digital video effects device which can be a separate standalone unit or can be an
integral part of production switcher.A typical digital video effects system consists of
the control panel, controller electronics to generate the required control signals to
define the effect, and the digital video processor which uses the control signals to
control the video signal in the digital domain producing the desired effect.
3d creativity
Imaging effects
Curvilinear effects
Painterly and particle effects
Slabs
Border effects
22
Lighting effects
Shadows
Dynamic recursive effects
Imaging effect
Ability to blur, and skew an image in both horizontal and vertical directions.
Unique matt colors for any and all layers in the system with adjustable Hue,
Luminance, Saturation and Opacity.
Curvilinear effects
Warps– Creation of bursts, radial bursts, slates, ramps, arrows, diamonds, rings,
balls, splashes, hour-glasses, and ripples.
Page turns– Allows to create page turns with ability to manipulate the turn’s size
position, axis, and angle of rotation. Different images can be placed on either side
of the page,
Page scrolls– Allows to create page scrolls with the ability to manipulate the
scroll’s size, position, axis, and angle of rotation. Different images can be placed
on either side of the page, with added ability to split the page in a number of
different ways.
Painterly and particle effects
Painterly effects allow modifying the texture surfaces with tiles, bubbles,
corrugation, crystallization effects and both stained and beveled glass effects.
Particle effects allow controlling the amplitude, axis and angle of particles to
create explosions, swirls, blowing sand, bursts, slats, and fuzz effect
Creating rectangular solids such as cubes and slabs. Any channel or input can be
assigned to any side of the cube.
Lighting effects
Automatic highlights, Manual highlights and reverse manual highlights with
control over the light’s X and Y position, aspect, radius, hue, luminance, and
saturation.
23
Border effects
Border can be placed on any combination of channels, with completely adjustable
hue, luminance, saturation, width and softness. A wide variety of border “types”
are available, including metallic tubes, frames, and bevels.
Figure 4.5. Light effects
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5. Satellite communication
Figure 5.1: Satellite communication
Satellite history
Started in 1957 in Russia (Sputnik)
Started in India on 14.04.1982 (INSAT 1A)
Advantages
1. Large coverage area (42% of Earth), very high B.W. (Wide band Multi Channel)
2. Terrestrial uncovered pockets like valleys and mountains regions.
3. Uniform Signal.
4. Establish easily for point to point communication.
25
5. During critical condition earth stations can be removed and relocated easily, timely
and communication can be established.
6. Satellite Costs are independent of distances, quality of signal is independent of
distances where as it not in the case of optic fibre cables.
Disadvantages of Satellite communication
1. Communication path between TX and Rx is approx.75000 Kilometres
2. The delay 270+270 m sec makes one feel annoying.
3. The delay reduces efficiency of sat. In data transmission during long file transfer.
4. High atmospheric losses above 30 GHz limit carrier frequencies
Satellite orbits
LEOs - Low Earth Orbit
MEOs - Medium Earth Orbit
GEOs - Geostationary Earth Orbit
6. Microwave link, optical fibre link & measurements
A microwave link is a communications system that uses a beam of radio waves in the
microwave frequency range to transmit video, audio, or data between two locations,
which can be from just a few feet or meters to several miles or kilometres apart.
Microwave links are commonly used by television broadcasters to transmit
programmes across a country.
Purpose of live links for coverage
(a) Live News Event
(b) Live Sport
6.1. Links for OB coverage System
(a) Micro Wave Link
26
(b) COFDM based digital wireless camera system.
(c) Optical fibre system.
(d) Satellite link (DSNG)
6.2. Wave propagation
Propagation of Radio waves takes place by different modes, the mechanism being
different in each case.
Based on that, it can be classified as:
1. Ground (Surface) waves
2. Sky (Ionosphere) waves
3. Space (Tropospheric) waves
Ground (Surface) Waves
Medium wave (MW) propagates along the surface of the earth. It is normally
vertically polarized to avoid short circuiting of the electric component by the ground.
Sky (Ionosphere) Waves
Short wave (SW) propagates as sky waves. Ionisation of upper parts of the earths
atmosphere plays a part in the propagation of the high frequency waves.
Space (Tropospheric) Waves
Space wave travel more or less in straight lines. As they depend on line of sight
conditions, they are limited in their propagation by the curvature of the earth.
Microwave is a space wave communication based on line of sight. Link between
30/60 Km. in single hop on flat surface at frequency range of 2 to 8 GHz is possible
using microwave.
With antenna fixed on mountain top a link up to a distance of 200 Kms are in
existence. These links have a frequency range between 2 to 24 GHz
27
6.3. Antennas
Microwave links are using two kinds of antennas.
1. Parabolic type
2. Horn Type
These antennas are highly directional. Parabolic antenna is the most commonly used
antenna having a feed, which is a microwave guide with its opening placed at the
focus of parabola structure. Wave guide opening is design in such a way to match the
impedance of wave guide to that of free space. Focus of a parabola structure is the
point where all the light energy falling
On it will converge. As both the light and the microwave are electromagnetic wave so
they have similar qualities. This suggests that all the electromagnetic energy will also
converge at focus of a parabola structure. Parabolic antennas used have a size vary in
different antennas.
Figure 6.1: simplified microwave link
28
Microwave transmitter link
Figure 6.2: Microwave transmitter
A standard 1 volt Video signal is applied to the transmit video Amplifier PCB input.
This unit processes the signal to the provide all parameters that are required by the
system before passing it to the Video Modulator PCB
Video Modulator
The transmit Video Modulator PCB takes a standard 1 volt composite video signal
(pre-emphasised with sound sub-carriers) and frequency modulates a 70 MHz voltage
controlled oscillator (VCO). The output of the modulator is FM modulated carrier at
70MHz.
29
Up-converter
The Up-converter processes the 70MHz IF product of the video Modulator stage to
produce a 1GHz RF signals. The 1GHz signal is amplified and passed through a
1GHz filter before it is applied to the power control stage.
Microwave Receiver Block Diagram
Figure 6.3: Microwave receiver
Down converter
The Down converter processes the 1GHz product of the first Mixer stage to produce a
70MHz IF signal. This 1GHz signal is filtered and amplified before being mixed with
a 930MHz signal to produce a 70MHz IF signal which is then passed to IF AGC stage
where it is further amplified and filtered.
30
Figure 6.4: Down converter
Video Demodulator
The Video Demodulator stage contain all the functions necessary to take a video FM
modulated IF signal at 70MHz, demodulate it to composite baseband (i.e. video plus
sound sub-carriers), amplify, de-emphasize and filter the video and separate off the
sub-carriers for subsequent demodulation
viii
CONCLUSION
At the DDK Jaipur we learn about the history of broadcasting and the basic idea of the
broadcasting means that what is broadcasting and need of broadcasting we also saw the
studio setup of DDK Jaipur and learn that how the we record the programme and then
after recording how the video is transmitted to satellite and another receiver and
intermediate process between transmitter and receiver means how they are mix the
audio and video and the key that are used on writing on video slide.
ix
REFERENCE
Images from Google https://googleimages.com
Content of broadcasting from Katson books(Analog communication)
Keying methods from Slideshare.com.
Broadcasting history from www.india360.com.
Report format from www.rtu.ac.in
Different wave propagation techniques from Antenna and wave
propagation by Dr,K.D. PRASAD
Modulation techniques from Katson books(Analog communication)