As long-distance transmissions are always required in the CATV systems, it is very necessary to make the quality of visual and audio signals in high levels after the long transmissions, so that the performance of the CATV systems can be ensured. To serve this aim, the CATV EDFA optical amplifiers are come up with and widely used in the CATV systems. Why the EDFA optical amplifier is needed in CATV system? How does it work for the long CATV application? The following text will give you the answers and simply introduce two typical CATV EDFA amplifier applications for your reference.
What’s CATV EDFA Amplifier?
CATV EDFA is a kind of optical amplifier, most commonly used in the long-haul CATV system for boosting the damped CATV signals, with the aim of compensating the signal loss. Since it mostly works as booster optical amplifier in the CATV system, so that it can be also called CATV booster amplifier. By utilizing the CATV EDFA optical amplifier, the CATV signals can be enhanced to meet the system requirement and then be sent to the users. However, when the signal power is improved by the CATV EDFA, the noise existing in the transmission link would also boosted and some return loss would also occur at the same time. Considering that, it is very necessary to choose quality CATV EDFA optical amplifier for ensuring the performance of CATV system, even if it may be cost a little higher than common optical amplifier.
Why CATV EDFA Optical Amplifier is Used?
CATV is a multi-channel TV system transmitting visual and audio signals from digital or analog television and radio channel to many users via fiber or copper patch cable. As the signals should be finally separated by optical splitter to serve more than one users and many loss has occurred in the long transmission, the overall speed and quality of the CATV signals would become too weak to meet the receiver requirements. Under this condition, the CATV EDFA optical amplifier is very essential for CATV system with the function of amplifying CATV signals and giving high performance systems to the users.
How Does CATV EDFA Work for Long CATV Applications?
A long CATV system is always composed of head end, transmitter, receiver, CATV booster amplifier and optical splitter. When the system runs, the CATV signals are provided by the head end, and need to be split into several signals by the optical splitter to serve the users. When the signals pass through the optical splitter, the signal power would be in a very low level. Hence, the CATV EDFA optical amplifier should be deployed after the receiver to improve the signal power, and the users can finally receive quality signals.
From the figure above, we can learn a simple point-to-multipoint CATV network design as mentioned above. The CATV signals are provided by the RF combiner and should be connected with four receivers by the optical splitter. In order to compensating the signal loss caused by the optical splitter, CATV EDFA optical amplifier is required before sending the weak signals to the users.
Except for this simple kind of CATV network using CATV EDFA optical amplifier, here also offers a complex CATV network, as designed in the figure below. In this CATV network, the CATV EDFA optical amplifier is deploy behind the 8 channel DWDM Mux Demux to amplify the signals while the 8 channel DWDM Mux Demux allows for higher capacity transmission. Hence, a long CATV network with big capacity can be achieved.
Conclusion
When deploying a long CATV system, we should pay attention to the loss caused by long transmission distance and CATV components. When the loss is very high, CATV EDFA optical amplifier would be an ideal device deployed in the long CATV system for improving the quality of CATV signals, so that the users can receive high speed and reliability of the services.
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