A variety of CATV Amplifiers are now available. Each type of CATV Amplifier offers a compromise between its technical specifications and price. An ideal CATV Amplifier should amplify the cable TV signal without adding any distortion or noise to the signal. While this definition may seem simple, it is almost impossible to implement.
TYPES OF AMPLIFIERS
The most basic type of commercial CATV Amplifier is the Transistorised Amplifier. These Amplifiers do not use a Hybrid IC. They use multiple amplifying stages implemented with discreet transistors. These low cost amplifiers are strictly speaking appropriate for Master Antenna TV applications rather than CATV applications. However, They are often used in small cable TV networks,
which deliver upto 24 channels for frequencies upto 300 MHz. Some manufacturers even offer transistorised amplifiers for operation upto 550 MHz. These low cost amplifiers are unsuitable for output levels above 90 dBU, with 67 channels driven simultaneously.
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The line extender amplifier is a Hybrid IC based, single stage amplifier that offers reasonable performance at an attractive price. Ideally, it should only be used on the branch and last mile paths. It does not offer the lowest level of distortion or noise and hence its use should be avoided on the trunk line. Bridger Amplifiers are usually Hybrid IC based amplifiers that offer high output levels to a branch, for distribution. Some times the Bridge Amplifier; as a module; is housed within the trunk amplifier enclosure.
Trunk amplifiers typically offer the highest level of performance and also cost the most. A trunk amplifier approaches the ideal amplifier i.e. it offers amplification with the least distortion and noise. Let us take a closer look at how this is achieved.
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