In this Article, I am gonna explained the types of color Television system
we have already known about the functioning and basic TV guide that all have studied in their schools for TV tube accelerator.
And color Television channel Antennas that transmitted Audio/Video signals through satellite channels.
Now we discussed about types of color Television or lets say that Antenna’s TV Systems.
Now I explain nearly 3 Types of systems are follows.
1. MATV (Master Antenna TV)
2. CATV (community Antenna TV)
3. CCTV (Closed Circuit Television)
MATV-Master Antenna TV of color Television
- One or more antennas are located on roof top,the number depending on telecast and their direction.
- Each antenna is located insuch direction that all stations are received simultaneously.matv systems are designed to have 75ohm impedance so that match between co-axial line and component is achieved.
- Antennas output are fed into 4 way hybrid.
- Hybrid is signal combining their mixer which provides impedance matching to avoid,standing waves. Standing waves result in ghost.
- The output from hybrid is fed to distribution amplifier by pre-amplifier. Functions of these amplifier is to raise signal to level sufficient to prevent losses of distribution system.
- The output from distribution amplifier if fed to splitters through co-axial line.
- Co-axial distribution lines carry color Television signals from output of splitters to point of delivery called subcarriers tap-off.
- These are either transformer coupled or capacitive coupled.
- They provide isolation between receivers thus prevent mutual interference.
CATV-Community Antenna TV
- The abbreviation of CATV stood for community Antenna Television which which means a common receiving antenna for community.
- The signal received by this common antenna was then distributed to large number of houses through network of co-axial cables.
- Such concepts is valid huge buildings having hundreds of apartments thus eliminating the need of each house to have its own dish on roof top.
- In the present day of cable TV, the cable TV operator has a root of receive only earth stations with a capability to receive telecast of one or more than one satellites.
- The received signals are then simultaneously transmitted over a distribution network of co-axial cables on single point to multi point connectivity basis to large number of houses known as his subscriber who pay monthly fee for this services.
- The cable TV operator also transmit over the distribution network the video tape recorded programs that they get from other sources in addition to showing programmes received from satellite.
Closed Circuit Television (CCTV)
- As the name implies, it is a system in which the circuit is closed and all element are directly connected.
- This is unlike broadcast Television where any receiver that is correctly tuned can pick up the signal from the airwaves.
- In closed circuit television system the video output from a TV camera is fed directly by a co-axial or low power wireless link to a specific type of TV receiver called a monitor which is installed at remote position so that the picture is produced on the screen of the monitor.
- A TV monitor or a video monitor is as ordinary TV receiver without the RF-IF stages.
- It produces the picture directly from composite video signal supplied by TV camera
- When a number of camera are used for monitoring at different locations a camera selector switch is used to select the signals from different cameras.
- CCTV is very useful system which finds many applications in education, industry, medicines and traffic controls.
Simple CCTV System
- The simplest system is a camera connected directly to a monitor by co-axial cable with the power for the camera being provided from monitor.this is known as line powered camera.
- The next development was to incorporate the output from four cameras into monitor.
- These could be set to sequence automatically through the camera.
Hope you got basic concepts regarding Antenna Televisions.
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