Studio Program, ENG & Transmission System on BTV
CHAPTER ONE
INTRODUCTION
1.1Preliminary
In 1964, Television Started broadcasting as a Corporation, named Pakistan Television Corporation. Transmission of the station initially began from DIT (Presently RAJUK Bhaban) for four hours duration. After independence in 1971, it was renamed as Bangladesh Television (BTV) and continued as corporation till 1972. Then BTV was given a status of a Department of the Government under the administration control of the Ministry of Information. Offices and studios of Bangladesh Television were shifted to Rampur a from DIT building on 9th February 1975. Being a state owned public broadcaster, BTV’s administrative and financial management is under control of the Government.
In the context of Bangladesh’s social perspective, the organization has earned the trust of its viewers for which the producers, artists and supporting manpower deserve commendation for their coordinated efforts, creativity and sincere devotion. Bangladesh Television takes pride in recollecting the memories of 1971 when the organization inspired the nation during our great war of liberation. BTV started Color Transmission in 1980. Since then the state-run media is pursuing a forward looking journey. Till 2003, as many as 14 relay stations, located all over the country, have been established. Thus 93 percent geographical area of the country has come under transmission coverage. BTV exchanges programme and news with other broadcasting organization on a regular basis. It is an important member of SAARC Audio Visual Exchange Programme (SAVE) and exchanges programmes among the broadcasters of the region. Bangladesh as a developing and peace-loving country has always extended its hands of cooperation with other nations. BTV is an important member of several international media bodies. As a member of Asia Pacific Broadcasting Union (ABU), Bangladesh Television joined the Satellite News Exchange programme under ABU when it was launched in 1984. BTV Transmits it’s transmission through 14 relay stations in the whole country, which has a
Potential coverage of about 95% of the territory and 95% of the population. Relay stations are as follows:
Natore,Sylhet,Khulna,Rangpur,Mymenshingh,Rangamati,Noakhali,.Shatkhira,Jhenidah,Thakurgaon,B’ Beria, Patuakhali,Rajshahi,Ukhia.1
1.2 Origin of this Report
The report entitled “Studio Programe ENG & Transmission System on BTV”: A case study on a Bangladesh Television” is the result of 4 months internship program in Bangladesh Television , Television Bhabon Rampura, Dhaka – 1219. To complete the internship and make this report, I had to do a literature survey on Television system, go through history of Bangladesh Television carry out thorough study on Television system, isolating the problems and finding out the solutions.
1.3 Organization of this Report
This report has been organized as below:
Chapter 1: In these chapter discuses about Preliminary, origin of this Report.
Chapter 2: In these chapter discuses about television overview.
Chapter 3: In these chapter discuses about BTV studio.
Chapter 4: In these chapter discuses about program studio.
Chapter 5: In these chapter discuses about programmed control room.
Chapter 6: In these chapter discuses about VTR-recording section.
Chapter 7: In these chapter discuses about Master control room.
Chapter 8: In these chapter discuses about Transmitting system of BTV.
Chapter 9: In these chapter discuses about ENG
Chapter10: Conclusion
CHAPTER TWO
TELEVISION OVERVIEW
2.1 About Bangladesh Television
Bangladesh Television is a Government sector effort, dedicated to the creative presentation of television technology for Bengal speaking people all over the world. Her I was successfully complete my internship .there are lots of section to known all kind of terrestrial broadcasting technology. I am personally chosen Master control room section .Because master room is the called mother section of all type of other technical section. this section maintain a high-level of quality control signal, technical efficiency and reliability while keeping up to date with state of the art technology .the signal is also sent to their uplink for cable distribution. Master control is the technical hub of a broadcast operation common among over the-air television station and networks. It is distinct from production control room in television studios where the activities such as switching from camera to camera are coordinated. Master control is the final point before a signal is transmitting over-the- air or sent on to a cable television operator or satellite provider for broadcast .Television master control room include bank of video monitors, satellite receivers, videotape machines, transmission equipment, and recently ,computer broadcast automation equipment for recording and playback of on-air programming.
Fig:2.1(Old DIT Bhaban) Fig:2.2 BTV Bhaban
In 1964, Television Started broadcasting as a Corporation, named Pakistan Television Corporation. Transmission of the station initially began from DIT (Presently RAJUK Bhaban) for four hours duration. After independence in 1971, it was renamed as Bangladesh Television (BTV) and continued as corporation till 1972. Then BTV was given a status of a Department of the Information Government under the administration control of the Ministry of. Offices and studios of Bangladesh Television were shifted to Rampur a from DIT building on 9th February 1975. Being a state owned public broadcaster, BTV’s administrative and financial management is under control of the Government. In the context of Bangladesh’s social perspective, the organization has earned the trust of its viewers for which the producers, artists and supporting manpower deserve commendation for their coordinated efforts, creativity and sincere devotion. Bangladesh 1
BTV exchanges program me and news with other broadcasting organization on a regular basis. It is an important member of SAARC Audio Visual Exchange Program me (SAVE) and exchanges programmers among the broadcasters of the region. Bangladesh as a developing and peace-loving country has always extended its hands of cooperation with other nations. BTV is an important member of several international media bodies. As a member of Asia Pacific Broadcasting Union (ABU), Bangladesh Television joined the Satellite News Exchange program me under ABU when it was launched in 1984.1
2.2 Vision
The vision of the present Government of Bangladesh is to make “Digital Bangladesh” by 2021 & we are working on it. BTV has a terrestrial coverage of 95% population through 14 relay stations
BTV has a plan to go the HD Television system.
Full Automation system will be introduced in BTV
Local programme of Chittagong station will be increased from one and forty five minutes
To six hours and also broadcast by satellite.
· BTV will construct a 12 storied official building in this campus.
· Bangladesh Television has adopted many projects to change the broadcasting system
Bangladesh Television will change the Terrestrial broadcasting system from Analog to Digital (DVB-T) within ITU time frame 2015.
Digital Terrestrial Transmission (DVB-T) will start from three place in Bangladesh like Dhaka, Chittagong and Khulna experimentally very soon.1
2.3 Mission
At present, BTV transmits 17 hours terrestrial programs from 7-00 AM to till mid-night including 14 news bulleting in English and Bengali daily. Besides, Chittagong sub-station air one hour & forty five minute local produced programmes every day.
Bangladesh has started “BTV World” Satellite Transmission on April 11, 2004. As a result BTV has now reaches. 1
2.4 Objectives
As a state run organization, it is accountable to the mass people of Bangladesh. It aims at the development of the lives of the people and socio-economic progress through its creative programs. The core objective of Bangladesh Television is to dissemination of information, extension of education, motivation for development activities and entertainment are the major principles followed by BTV for its broadcasting. National and international news, documentary and development programs and various entertainment programs are aired by BTV. For international news BTV gets supports from international News agencies and broadcasters. On the other hand, BTV imports some foreign entertainment programs. However, for national news, documentaries and entertainment programs, BTV produces programs by itself. Besides, local production houses have come forward with their productions and BTV televises the programs on terms and conditions agreed to both.1
2.5 Goals
Bangladesh Television will be the absolute media lender in the number of loans given to large sized enterprises throughout Bangladesh. It will be a world class television in Transmission system. BTV World is intended to extend its collaboration of reciprocal exchange of Programmes of non-discrepant quality with any Satellite Channel in the World .1
CHAPTER THREE
BTV STUDIO
3.1 BTV News studio
Fig: 3.1 BTV news studios
3.2 BTV new launce digital studio
Fig: 3.2 BTV new launce digital studios.
CHAPTER FOUR
PROGRAM STUDIO
4.1 Introduction
A complete TV Studio is in acoustically treated compact anechoic room .It is suitably furnished and equipped with flood lights for Proper light effects. The use of dimmer stats with flood lights enables suitable illumination level of any particular area of the studio depending on the scene to be televised .several cameras are used to telecast the scene from different angles similarly a large
Numbers of microphones are provided at different locations to pick up sound associated with the programmer. The camera and microphone outputs are fed into the control room by coaxial cables
4.2 Lighting system
Fig: 4.1 lighting system
Lighting or illumination is the deliberate application of light to achieve some practical or aesthetic effect. Lighting includes the use of both artificial light sources such as lamps and light fixtures, as well as natural illumination by capturing daylight. Day lighting (using windows, skylights, or light shelves) is often used as the main source of light during daytime in buildings. This can save energy compared with artificial lighting, which represents a major component of energy consumption in buildings. Without proper design, energy can be wasted by using too much light, or using out-dated technology. Proper lighting can enhance task performance, improve the appearance of an area, and have positive psychological effects on occupants. One of the central dogmas of proper lighting is that a uniform illumination is required in many applications
4.3 TV studios camera
Fig:4.2 TV studios cameras
A television camera produces corresponding video signal upon receiving light from a scene or subject. It is also called professional video cameras used for electronic motion picture acquisition, initially developed by the television industry but now common in other applications as well. It is known that John Logic Baird discovered Television in 1925-27, but employing the technique of electromechanical scanning of Pal Nippon’s rotating disc. The all-electronic television system, employing the camera tube “Iconoscope” and cathode-ray-tube was first demonstrated by V.K. Zworykin at the Wasting House Research laboratories, U.S.A. in 1924-29. This was the first black and white (B/W) television developed. Since then a lot of changes and improvements were made on television camera pickup devices, its associated electronic circuits and facility in early days comparatively bigger size television camera employing bulky camera tube Image Orthicon (abbreviated I.O. camera) were seen in television studios for B/W program production. This camera was then gradually replaced by smaller size B/W TV camera, constructed using small size tubes Videocon and plumb icon. The camera tube Videocon was in 1949, the Radio Corporation of America (RCA) developed the first color television system compatible with monochrome or B/W television. Its system is standardized as NTSC system. Later on modified systems SECAM in France and PAL in Germany were introduced.
In the past decades we saw two varieties of television cameras. Television broadcasting stations used more costly high quality three-tube color video camera for high quality color television production. While, other video amateur personnel had their own less costly single tube color video camera for video home service (VHS) production, e.g. birth-day, marriage ceremony. Two types of professional video cameras: High end portable Camcorders used for ENG and EFP image acquisition and studio cameras which lack the recording capability of a camcorder, and are often fixed on studio pedestals. Professional camera with video-audio recording facilities is called Camcorder. Camcorders are generally much larger than consumer cameras and are designed to be carried on the shoulder. If the pickup device is a plumb icon tube, its target plate builds up a pattern of electrical charges corresponding to the light and shade variations in the image. An electron beam generated within the camera tube scans this charge pattern line by line, re suiting a varying output voltage, called video signal.
4.4 Camera lenses
Television camera can produce images to different scales depending on the focal length (viewing angle) of the lens employed. Narrow lenses (below 200) are suitable for close-ups of distant objects because of the magnifying effect due to their longer focal length. Lenses with angles over 600.medium angle lenses (20 to 600) are called universal lenses and used for television normal scenes.
4.5 Zoom lenses
Zoom lenses have a variable focal length with a range of 10:1 or more. In this lens the viewing angel and field. View can be varied without loss of focus. A zoom lens can in principal simulate any fixed lens which has a focal length within the zoom range. In many camera units only a zoom lens is provided instead of the turret lens assembly. This alone enables the camera operator to have close-ups, wide converge of the scene and distant shots without loss to focus. Boom operators manipulate boom arms for distinct sound pick-up yet keeping
4.6 Camera mounting
Cameras are mounted on light weight tripod stands with rubber wheels to enable the operator to shift the camera as and when required. It is often necessary to be able to move the camera up and down and around its central axis to pick-up different section of the scene. Typically provide a 3600rotational capability and allow tilting action of plus or minus 900.
4.7 View finder
The camera operator to frame the scene and maintain proper Focus, an electronic, view-finder is provided with most TV camera. This view-finder is essentially a monitor which reproduces the scene on a small picture tube. It receives video signal from the control room stabilizing amplifier.
4.8 Audio Pick-up
The location and placement of microphones depends on the type of programmed .A microphone a movable platform. The booms carry microphones close to the area of pick-up but keep them high enough to be out of the camera range
4.9 Microphone
Microphone is a device which converts sound energy into electrical energy. Without microphone we cannot think our audio-visual production, transmission and recording
4.9.1 Kind of microphone:
Capacitor microphone, foil electrets microphone, dynamic microphone, ribbon microphone, carbon microphone piezo microphone one reacts with sound wave and converts it into audio signal. Directional Response specifies the directional characteristics of microphone. Directional pattern shows how the microphone response varies with the direction of the incident sound wave. Three basic directional patterns
Fig: 4.3 Omni directional microphonesFig: 4.4Cardioids Microphone
Fig: 4.5Super cardioids Microphone
Fig:4.6 Senn microphone
CHAPTER FIVE
PROGRAMMED CONTROL ROOM
5.1 Lighting control panel
Fig: 5 .1 lighting control panel
BTV Digital lighting control panel .Different lighting system is used for different program.
5.2 Audio panel
Fig: 5.2 Audio panels
5.3 video switcher
A video switcher is a multi contact crossbar switcher matrix with provision for selecting any or more number of inputs and switching them on to outgoing circuit the input sources include cameras, VTRs and telecom outputs, besides tees signals and special effects generators
Fig:5.3 video switcher
5.4 C.C.U
The camera control unit has provision to control zoom lens action and pan-tilt movement besides beam focus and brightness control of camera tubes .The C.C.U engineer manipulates various controls under directions from the producer .The C.C.U. engineer has the necessary facilities to adjust parameters such as video gain, camera sensitivity, backing level video polarity etc .For live broadcast of programmers televised far away from the studios, microwave links are used. The modulated composite video signal receive over the microwave link is demodulated and processed in the usual manner by the C.C.U. engineer for transmission on the channel allocated to the station.
CHAPTER SIX
VTR-RECORDING SECTION
6.1 Linear
Linear video editing is the craft of using two videotape machines to create a final video master. It involves copying video from one machine to another with a controlling device. Shots are recorded onto the second machine in their final sequence.
Fig:.6.1 linear
6.2 Non-linear
In digital video editing, non-linear editing (NLE) is a method that allows you to access any frame in a digital video clip regardless of sequence in the clip. This method is similar in concept to the “cut and paste” technique used in film editing from the beginning. This method allows you to easily include fades, transitions, and other effects that cannot be achieved with linear editing. Video and audio data are first captured to hard disks or other digital storage devices. The data is either recorded directly to the storage device or is imported from another source. They can be edited on a computer using any of a wide range of software. Digital nonlinear systems provide high-quality post-production editing on a desktop computer. However, some detail may be lost if loss compression is used to store the images.
Fig: 6.2 Non-linear
A non-linear converts that linear tape into digital media through the DV interface
6.3 Digital video studio
Fig: 6.3Digital video studio
6.4 Terminal
The terminal area is where all the various audio and video lines terminal this is also central hub for the phone and computer networks
6.5 Audio Mixer
A good quality pro audio mixer can literarily mean the difference between a successful event and an audio nightmare. If the levels are not correctly mixed, this can result in a “muddled” sound. Finding a good pro audio mixer can difficult, however, especially if you happen to be on a budget. Cheaper models can tend to fail when you need them most, and many of the professional-grade models are extremely expensive. There are some great affordable mixers out there; you just have to know what to look for.
It is a good idea to know some of the basics of amplification and sound mixing in order to get the absolute most out of your sound mixer. Electronic sound is produced when acoustic sounds, either through an instrument or a voice, are converted into an electric sound via a microphone or a pickup. This electric signal is then sent to an audio mixer.
Fig: 6.4Audio Mixer
6.6 video Mixer
Fig:6.5 video Mixer
6.7 Video tape Recorder
Fig: 6.6Video tape Recorder
There are three set of video tape recorder. A video tape recorder is a tape recorder that can record video material. The video cassette recorder ,where the video tape is enclosed in a user friendly video cassette shell is the most familiar type of VTR known to consumers professionals may use other types of video tapes and recode’s.
CHAPTER 7: MASER CONTROL ROOM
7.1 Introduction Master control Room
Master control is the technical hub of a broadcast operation common among most over-the-air television stations and television networks. It is distinct from a production control room (PCR) in television studios where the activities such as switching from camera to camera are coordinated. A transmission control room (TCR) is usually smaller in size and is a scaled down version of central casting. Master control is the final point before a signal is transmitted over-the-air for terrestrial television or cablecast, satellite provider for broadcast, of sent on to a cable television operator. Television master control rooms include banks of video monitors, satellite receives, videotape machines, video servers, transmission equipment, and, more recently, computer broadcast automation equipment for recording and playback of television programming. Master control is generally staffed with one or two operators around-the-clock, every day to ensure continuous operation. Master control operators are responsible for monitoring the quality and accuracy of the on-air product, ensuring the transmission meets government regulations, troubleshooting equipment malfunctions, and preparing programming for play out. Regulations include both technical ones (such as those against over-modulation and dead air), as well as content ones (such as indecency and station ID).Many television networks and radio networks or station groups have consolidated facilities and now operate multiple stations from one regional master control or central casting center. As an example of this centralized broadcast programming system
V.trangv delay Vda in1
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News Pgm
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Derma
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SmallPST
Fig: 7.1 MCR
CHAPTER8: TRANSMITTING SYSTEM OF BTV
8.1: Terrestrial Transmitting system
Bangladesh television is terrestrial transmitting system three equipment using. Optimum analogue liquid cooled VHF-B3 TV equipment 10K0 DD T5015 BANGLADESH (THALES).BTV Dhaka HK transmitter. Optimum, Analogue Liquid cooled.
Optimum analogue liquid cooled VHF-B3 TV equipment 10KoDD T5015 BANGLADESH (THALES)
Fig: 8.1 BANGLADESH (THALES
Adjustment controls the sensitivity controls on the front of the PCL are used to set the parameters, which are displayed by the bar graphs on the PCL and the<< RF REFLECTED LEVEL>>AND<<RF LEVEL>> windows: These adjustments set the input signals and as follows: R435: sensitivity control for Vision power indication
R404: sensitivity control for sound 1 power indication
R421: Sensitivity control for sound 2 powers (IRT-NICAM)
R475: sensitivity control for antenna SWR indication
R455: sensitivity control for indication of Vision SWR ahead of filter unit
R505: sensitivity control for indication of sound SWR ahead of filter unit.
Exciter section:
Video signal Input Performance
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Eliminate the unwanted video
Component.
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Compensation of the phase distortion.
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White clipping sync .stretching and clipping
Pedestal Clamping.
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If modulation pedestal feedback Pedestal
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VSB Filter group Delay correction
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Generate the local oscillator
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This Equipment is only use Parallel operation system
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Phase Linearity correction
Amplitude linearity correction
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In demodulation correction
Convert IF Band signal in
VHF Band signal
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Reject the unwanted inter modulation
To power amplifier
Fig: 8. 2 Exciter section (Video signal)
Low pas filter: this unit consists of the l PF and phase equalizer to eliminate the unwanted video components in excess of 5 MHz and compensate the group delay characteristics occurred by using of LPF.Color phase equalizer: this unit is used for compensation of the phase distortion in the TV transmitter and receiver to achieve a high fidelity transmission of color signals. VIDEO corrector: this unit has the following functions white clipping synch stretching and synch. Clipping pedestal clamping. Visual modulator: the diode balanced modulation is accomplished and the pedestal feedback circuit is included in this unit.VSBF &CORRECTOR: This unit designed with active circuit to compensate the phase distortion caused by VSB filter Face Linearity corrector Section: This section contains following functions as shown: 1). Amplifier .2) phase linearity correction3) Automatics gain control circuit V&A Mixer: This unit its used for conversion of the IF visual and aural modulated signal to the required frequency with a local signal. Local Oscillator: This unit is used for Supplying of the two required local signal and one frequency check output from the crystal oscillator unit. AURAL MODULATOR: The Vari-cap diode modulation is accomplished and the APC.(Automatic phase Control) circuit is included in this unit. REGULATED POWER SUPPLY: This unit is employed to supply the regulated power source for exciter modules in VHF& VHF TV transmitters. Band pass filter Unit: band-pass filter is used in connection of VHF Frequency converter to reject the unwanted inter modulation generated in the converter. RF AMLIFIER: RF Amplifier is used mainly to small output Amplifier for TV transmitter .This unit is designed for wide band operation or narrowband operation.40-270MHZ.Regulated Power Supply: this unit is employed to supply the regulated power source for transistor power amplifier unit. MAX .voltage 16v
MAX. Current 4APower Amplifier Section: This paragraph describes the transistor power amplifier .the electron tube power amplifier the power supply circuit, and cooling system for them
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Aural signal input
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….Same as visual
…………………..If modulation Automatic phase control
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Same as visual signal
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Same as visual signal
To aural power Amplifier section
Fig8. 3 Exciter section (Aural signal input)
The two exciter changeover modes (Dual drive version)
In the automatic changer mode the facilities for an automatic switch between the two exciters (A-B or B-A) if a fault appears on the selected exciter channel have been enabled; in this mode it is possible to initiate the changer over manually. In the automatic changeover mode the identity of the selected exciter is not changed; this is not the case with manual changeover. In the manual changeover the switch can only take place as a result of a command from a user interface (PCL or remote user interface) Interface (PCL or remote user interface)
Modulation:
Two type of modulation are occurred in the substation. Those are audio modulation and video modulation. Several electrical and mechanical instruments are responsible for both types of modulation .an electrical machine named “THELES” Mainly controls the transmission section of modulation unit in BTV .It is a air cooled solid stated (double drive) device .It used Band-7 transmission with the Transmission power of 10kw+10kw.The exiting section of the transmitter is 2 types such as A-exciter and B-exciter. Every type exciter has 5 modules. Two type of modulation in BTV station discussed on the following-
Video Modulation:
In AM transmitters where efficiency is the prime requirement, amplitude modulation is affected by making the output current of a Cass C amplifier proportion to the modulation voltage. On the other hand, in an AM transmitter, amplitude modulation can be generated at any point after the crystal signal oscillator .From the transmitter section of BTV the output signal goes to “power amplification section” where rectification of amplitude modulation signal at 557 MHz is happened in many stage .the IF stage for video signal is about 38.9 MHz
Audio Modulation:
We know that at the transmitter, the audio signal is frequency modulated and it transferred to assigned channel sound carrier frequency by the use of multipliers .It later amplified through several stages of power amplifier to raise the power output to desired level .Audio monitors are provided at various point to keep a check on the sound quality .The BTV IF stage for audio signal is 33.4MHz.Though the “THELES” performs both analog system &digital modulation in TV system ,there are also two more electrical machine as the transmission section of BTV .One is NEC and the other is AXCERA .The NEC is the product of Nippon Electronics of Japan, which used in BTV .It is tube type transmitter and needs 400kw power to operate .But it is not more efficient than previous TV transmitter THELES .The other one named AECERA ,made by America, is the new one, which installed in the substation some months ago .it supports the digital transmission .Now ,it is developing its for the new Gove channel “Sanged Bangladesh” that will be lunched soon in Bangladesh Through all TV substation.
Amplifier:
In the TV station of the transmitter is THELES (model number: TAV 210 K0ADDB3) which is made in France. This transmitter follows heterodyne action. It has 10 amplifiers.1st and 10th amplifiers used for video amplification .Those amplifier is missing in the transmitter without creating any problem in total transmission system.
Mixing: we have discussed previously about this section in the signal reception and transmission section. In this section, the video signals are both multiplexing through the machineries by a constructive way. The machine is called the De -multiplexer .It has transmission line .The valuable cooling system is need for the machine to work properly always to continue the signal transmission on the through the transmission Links
Transmission: after mixing the AM and FM signal by de-multiplexer machine a path from the machine is constructed to transmit to transmit the mixed signal .the path is made of high Quality steel to close the occurrences of errors in line. The antenna through the transmission line transmits the mixed signal. Those transmission equipments placed outside of the TV station .some practical in formations of antenna and transmission line given below-
Local Oscillator:
This circuit provides a local oscillation frequency required for converting the visual and aural I.F signals into the VHF television wave band. This oscillator multiplies twice or directly the output from the crystal oscillator to feed it to the HPA-2228 V &A mixer (V& A Mix)
Power supply: The Dc Regulated Power supply Unit Supplies the modulation exciter with power. This unit is equipped with a protection circuit against over voltage and over-current for safety of the load circuit and itself.
Antenna:
Fig: 8.4 antenna of the Bangladesh BTV
The main antenna of the Bangladesh. Which is Omni directional? Its general height is 500ft high tower on ground .the antenna power is about 10kw for visual sync peak output .The gain of antenna 9/6 db. For the better receiving of signals by the TV set, there must be have a Yagi – Uda antenna on the roof or open place of the building that is called directional antenna.
8.2 Terrestrial frequency Distribution
Terrestrial television is a mode of television broadcasting which does not involve satellite transmission or cables — typically using radio waves through transmitting and receiving antennas or television antenna aerials. The term is more common in Europe, while in the United States it is referred to as broadcast television or sometimes over-the-air television (OTA) and requires a Tuner (television) to view content. Terrestrial television broadcasting dates back to the very beginnings of the broadcast television system as a medium itself with the first long-distance public television broadcast from Washington, D.C., on April 7, 1927. The BBC began broadcasting television to the public in 1929, and had a regular schedule of television programmers in 1930. Aside from transmission by high-flying planes moving in a loop using a system developed by Westinghouse called Stereovision, there was virtually no other method of television delivery until the 1950s with the beginnings of cable television, or community antenna television (CATV).
Frequency Distribution of BTV
BTV uses for terrestrial broadcasting VHF band-3 Frequency (174-230 MHz)
| SL.No: | Station | Channel No. | Power(KW) | Frequency(MHz) | Line description |
| 01 | Dhaka | 9 | 10+10=20 | 202-209 | 625 Lines 50Hz |
| 02 | Chittagong | 5 | 10 | 174-181 | |
| 03 | Khulna | 11 | 10 | 216-223 | |
| 04 | Rajshahi | 12 | 10 | 223-230 | |
| 05 | Sylhet | 7 | 10 | 188-195 | |
| 06 | Rangpur | 6 | 10 | 181-188 | |
| 07 | Thakurgoan | 10 | 10 | 209-216 | |
| 08 | Patuakhali | 7 | 10 | 188-195 | |
| 09 | B -baria | 5 | 10 | 174-181 | |
| 10 | Jhenaidah | 5 | 10 | 174-181 | |
| 11 | Shathkhira | 7 | 10 | 188-195 | |
| 12 | Natore | 8 | 10 | 195-202 | |
| 13 | Noakhali | 12 | 10 | 223-230 | |
| 14 | Rangamati | 8 | 10 | 195-202 | |
| 15 | Ukhia | 10 | 10 | 209-216 | |
| 16 | Mymensing | 12 | 10 | 223-230 |
Table: 8.1 Frequency Distribution of BTV and Substations.
Satellite transmitting system
8.3 Satellite frequency distribution
Earth Station location |
Latitude |
Longitude |
Satellite |
Satellite location |
TV Bhaban Rampura Dhaka |
23º 45´56.3´´ |
90º 25´21.1´´ |
Asia Sat-3 |
105.5º East |
Table: 8.2 Earth Station for BTV world
Technical Parameter of BTV World
Down Link Frequency |
3710.5 MHz (V-Pole) |
Symbol Rate |
11.3946 Ms/S |
FEC |
3/4 |
BW |
15 MHz |
Encoding |
MPEG-2, 4:2:0 |
Modulation |
QPSK |
Mode of Operation |
FT A (Sometime BTV National encrypted) |
Table: 8.3 Technical Parameter of BTV World
Technical Parameter of AVN
Down Link Frequency |
4104.5 MHz (V-Pole) |
Symbol Rate |
6.6665 Ms/S |
FEC |
3/4 |
BW |
9 MHz |
Encoding |
MPEG-2, 4:2:0/4:2:2 |
Modulation |
QPSK |
Mode of Operation |
FTA |
Table: 8.4 Technical Parameter of AVN
Fig: 8.5 Technical Parameter of AVN
Coverage Area of BTV World
Total Region of Asia All
Countries of Middle East region few countries of Africa Numerous small island of Micronesia, area of Philippine Sea and of Pacific Ocean region the islands of total Melanesia area of Oceania region few islands countries of Polynesia region
Satellite system
In general, a satellite is anything that orbits something else, as, for example, the moon orbits the earth. In a communications context, a satellite is a specialized wireless receiver/transmitter that is launched by a rocket and placed in orbit around the earth. There are hundreds of satellites currently in operation. They are used for such diverse purposes as weather forecasting, television broadcast, amateur radio communications, Internet communications, and the Global Positioning System, (GPS).
The first artificial satellite, launched by Russia (then known as the Soviet Union) in the late 1950s, was about the size of a basketball. It did nothing but transmit a simple Morse code signal over and over. In contrast, modern satellites can receive and re-transmit thousands of signals simultaneously, from simple digital data to the most complex television programming.
8.3.1 There are three types of communications satellite systems.
A low-earth-orbit (LEO) satellite system employs a large fleet of “birds,” each in a circular orbit at a constant altitude of a few hundred miles. The orbits take the satellites over, or nearly over, the geographic poles. Each revolution takes approximately 90 minutes to a few hours. The fleet is arranged in such a way that, from any point on the surface at any time, at least one satellite is on a line of sight. The entire system operates in a manner similar to the way a cellular telephone functions. The main difference is that the transponders, or wireless receiver/transmitters, are moving rather than fixed, and are in space rather than on the earth. A well-designed LEO system makes it possible for anyone to access the Internet via wireless from any point on the planet, using an antenna no more sophisticated than old-fashioned television “rabbit ears.”Some satellites revolve around the earth in elliptical orbits. These satellites move rapidly when they are near perigee, or their lowest altitude; they move slowly when they are near apogee, or their highest altitude. Such “birds” are used by amateur radio operators, and by some commercial and government services. They require directional antennas whose orientation must be constantly adjusted to follow the satellite’s path across the sky.
Satellite Ling: there are three orbital deviation in the whole world for the satellites which are Leo (used for lower communication), MEO (used for mobile communication) and Geo (used in TV signals transmission and reception).The Geo has 3region in the world.
Azimuth and Elevation:
Fig: 8.6 Flyaway antenna.
Azimuth and elevation are the two basic coordinates used to determine each satellite’s position in the sky. The azimuth coordinate represents the bearing of the satellite from the site location, while the elevation is the angle at which the antenna tilts up toward the sky .Every geostationary satellite visible from the site location has its own unique pair of azimuth and elevation coordinates.
Every satellite within view of a specific installation has its own unique pair of azimuth and elevation coordinates.
Fig: 8.7 satellite instrument setup.
8. 3. 3 The uplink model To satellite transponder
UP Converter
Baseband in FDM IF RF
RF
Fig: 8.8 the uplink model
The primary component within the Section of a satellite system is the earth station transmitter. Atypical earth station transmitter consists of an IF modulator, an If to RF microwave up-converter, a high Power amplifier (HPA).THE IF modulator converters the input baseband signal to either (mixer or BPF) converters the IF to an appropriate RF carrier frequency. The provides adequate input sensitivity and output power to propagate the signal to the satellite transponder. The HPA’s commonly used are klystrons and TNT’s
8.3.4The satellite transponder
A transponder is a part of a satellite, which is a combination, is a combination of transmitter and receiver. The main function of transponder is frequency translation and amplification. Based on the frequency translation process, there are three basic transponder configurations. These are single conversion transponder, double conversion transponder and regenerative Trans.
To earth station 12GHzFrom To earth station 4-12GHz
Oscillator
Fig: 8.9The satellite transponder
The uplink signal is received by the receiving. The receiving signal is first band limited by Band Pass Filter(BPF),then it is routed to low Noise Amplifier(LNA).The amplified signal is the then frequency translated by a mixer and an oscillator. Here only the frequency is translated from high –band up-ling frequency to the low-band down link frequency. The mixer output (down link signal) is then applied to BPF then it is amplified by a High Power Amplifier(HPA).This down link I s then transmitted to receiver earth station through a high power transmitting antenna.
8.3.5The downlink:
From satellite transponder
IF
RF
Base
Band RF
Fig: 8.10The downlink
An earth station receiver includes an input BPF, an LNA and an RF to RF to IF down converter. The BPF limits the input noise power to the LAN. The LAN is a highly sensitive, low noise device. The RF-to-IF down converter is a mixer, BPF combination which converts the received RF signal to an IF frequency. The most common frequencies used for satellite communication are 6/4 and 14/12 GHz band. The first number indicates the uplink (transponder-to-earth station) frequency and the second number is downlink (transponder-to-earth station) frequency. Since C band is most widely used, this band is becoming overcrowded. A typical C band transponder can carry 12 channels, each with a bandwidth of 36MHz.
8.5 PAL, NTS C, SECAM
PAL ,short for Phase Alternating Line, Pheanase Alternation by Lime or for Phase Alternation Line, is a color encoding used in broadcast television systems, used throughout the world except in most of the Americas ,some East Asian countries(which use NTSC),parts of the Middle East and Eastern Europe ,and France(which use SECAME .though most of them are in the process of adopting PAL).PAL was developed in Germany by Walter Brunch,working at Telefunken,and first introduction in 1967.Note that French Thomson ,where Henri de France develop SECAM .later brought Telefunken .Thomson is also behind the RCA is a trademark used by three now separate companies descended from a common ancestor: the Radio COM portion of America. Various product line and business interests of these companies now carry the RCA brand. History of RCA during World War the pat brand for consumer electronics products, and RCA is a trademark used by three now separate companies descended from a common ancestor. The Radio Corporation of America. Various product line and business interests of these companies now carry the RCA band. History of RCA during World War I the pat created the NTSC color TV standard (before Thomson got involved).
NTSC:
NTSC the analog television system in use in the United States and many other countries, including most of the Americas and some parts of East Asia .It is named for the National Television Systems(s)committee the industry-wide standardization body that created it .The National Television Systems Committee was established in 1940 by the Federal Communications Commission to resolve the conflicts which had artisan between companies over the introduction of a nationwide analog television system in the US. The committee in March 1941 issued a technical standard for black and white television .In January 1950 the committee was reconstituted ,this time to decide about color television, and in March 1953 it unanimously approved what is new called simply the NASC color television standard. The updated standard retrained full backwards compatibility with older back and white television sets. The standard has been adopted by many other countries, for example most of the Americas and Japan.
SECAM
SECAM(Sequential Cooler avec memoire, French for “sequential color with memory ”is an analog color television system first used in France .SECAM has been invented by a team lead by Henri de France and working at Thomson .It is historically the European color television standard. Thomson invented SECAM. It is, historically, the first European color television standard.
CHAPTER-NINE
ENG
9.1 Introduction
ENG is a broadcasting (usually television) industry acronym which stands for electronic news gathering. It can mean anything from a lone broadcast journalist reporter taking a single professional video camera out to shoot a story, to an entire television crew taking a production truck or satellite truck on location to do a live television news report for a remote broadcast ne