Cable TV System basics
This page on television basics tutorial covers Cable TV system basics. It explains cable TV system modules viz. cable station, multiplexer, amplifier, cable, feeders, cable TV box etc.
Cable TV is the system where in TV signal is delivered to the users using coaxial cable rather than radio waves. A cable TV company collects all the TV signals and multiplexes them. Later multiplexed signal is delivered to the subscribers. A channel decoder box in the subscriber premises select the desired channel and feed the same to the TV set.
The complete cable TV system is depicted in the figure above. CATV companies offer the cable TV service.
Let us understand the entire process:
• Cable TV companies collect broadcasted TV signals using very high gain TV antennas. This place is also referred as headend.
Later these received TV signal programming is re-distributed.
• The collected different frequency signals are multiplexed and amplified.
• This amplified signal is distributed to the subscriber homes using coaxial or fibre optic cables.
The coaxial cable will be usually 75 Ohm RG-59/U.
• The signal is connected to cable box in the subscriber premises.
This cable box houses Local oscillator or synthesizer. Based on user selection respective channel is selected and provided to the
TV set.
Special signal processing is applied such as amplification and impedance matching to the TV signals. In case of received satellite TV signals, frequency translation is carried out to make the signal compliant to the cable by the cable company before they are transmitted using the cable.
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