26-11-2012, 12:40 PM
REPORT ON INDUSTRIAL TRAINING DOORDARSHAN KENDRA PRASAR BHARTI
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An Overview
Doordarshan Kendra Gwalior is part of the DD India, the largest televisionnetwork in the world. Doordarshan with over 5 high power Terrestrial Transmitters,62 low power,5 very low power transmitter and 3 production centers serve M.P. Inaugurated on 28th may 2000 by the then broadcast minister mr. ARUN JATELY. Doordarshan Kendra gwalior currently produces and telecasts 168 hrs of local programmes per week.Now more than 85 per cent of the 60,385,118 populations of M.P., With the introduction of DTH almost cent percent of the population can now receive DDK Gwalior programmes without cable connection. Doordarshan studios have been established at Gwalior, Bhopal and Indore to foster regional diversity. People all over India are watching Doordarshan’s programmes. It is also received in 64 countries spread over the continents of Asia, Africa, Europe, Australia and America. TV Scenario in M.P. As per the 2001 census there are 60,385,118(5.5 million) house holds in M.P., 74.9 per cent of them are in the rural sector (44,42550) the remaining 25.1 per cent (13,52656) are in the urban sector. In 2001, 38.8 per cent of the households owned TV sets . Of these 62.3 per cent were in rural areas and the remaining 37.7 per cent in urban areas. Even if we estimate 10 – 15 per cent growth per annum. Of these estimated 3 million TV households 40 – 45 per cent is estimated to have cable connection i.e., 1.3 million and the remaining 1.7 million are without cable connection, and totally depend on DDK Bhopal for their TV viewing. The introduction of DTH, DD Direct Plus has considerably increased DD viewership in MP. From the available sales estimates of set top boxes and receivers it is estimated that MP has 3 to 4 lakh DTH households.
FUNDAMENTAL OF MONOCHROME AND COLOUR TV SYSTEM:- Picture formation:-
A picture can be considered to contain a number of small elementary areas of light or shade which are called PICTURE ELEMENTS. The elements thus contain the visual image of the scene. In the case of a TV camera the scene is focused on the photosensitive surface of pick up device and a optical image is formed. The photoelectric properties of the pick up device convert the optical image to a electric charge image depending on the light and shade of the scene (picture elements). Now it is necessary to pick up this information and transmit it. For this purpose scanning is employed. Electron beam scans the charge image and produces optical image. The electron beam scans the image line by line and field by field to provide signal variations in a successive order.
Number of TV Lines per Frame:-
If the number of TV lines is high larger bandwidth of video and hence larger
R.F. channel width is required. If we go for larger RF channel width the
number of channels in the R.F. spectrum will be reduced. However, with more
no. of TV lines on the screen the clarity of the picture i.e. resolution improves.
With lesser number of TV lines per frame the clarity (quality) is poor.
The capability of the system to resolve maximum number of picture elements
along scanning lines determines the horizontal resolution. It means how many
alternate black and white elements can be there in a line. Let us also take
another factor. It is realistic to aim at equal vertical and horizontal resolution.
Therefore, the number of alternate black and white dots on line can be 575 x
0.69 x 4/3 which is equal to 528.
The Colour Television
It is possible to obtain any desired colour by mixing three primary colours i.e., red, blue and green in suitable proportion. Thus it is only required to convert optical information of these three colours to electrical signals and transmit it on different carriers to be decoded by the receiver. This can then be converted back to the optical image at the picture tube. The phosphors for all the three colours i.e. R, G and B are easily available to the manufacturers of the picture tube. So the pick up from the cameras and output for the picture tube should consists of three signals i.e. R, G and B. It is only in between the camera and the picture tube of the receiver we need a system to transmit this information.