Introduction
Various kind of networks are implemented for delivery of various services. For cable tv industry Optical Fiber Network as well as Coaxial Cable Network is implemented in field for proper delivery of TV Channels Services, Broadband Services and Voice.
So in this article we will cover what is HFC network, Implementation and working of HFC Network.
What Is HFC Network
HFC Network stand for Hybrid Fiber Coaxial Network. Which indicates that Fiber Network and Coaxial Network both are used in this Network.
In CATV industry we uses the Fiber Network with coaxial network for delivery of services, is a good example of HFC Network. For converting the Fiber network into Coaxial Network we use the HFC Node in field. These nodes are the active devices which need external power supply for working. So it works as converter from fiber network to coaxial network.
Working Of HFC Network
As shown above in the figure there is Headend which can be called here as a HUB. In this headend system the output of the CMTS and QAM is mixed together and then send to the NODE via OFC. This node convert the fiber signal into coaxial signal. After this coaxial signal goes into the amplifier for amplification. Then this coaxial signal is distributed to various customers available in the field. The distance between HFC Node and Headend can be 50 KM or more than that.
The HFC Network provides the downstream of 4.3 Gbps while upstream of 100 Mbps. Where downstream frequencies are from 54 – 750 MHz and upstream frequencies are from 5-42 MHz.
108 – 137 MHz = Aeronautical Mobile and Radio Navigation Frequencies
328 – 355 MHz = Aeronautical Glideslope Frequencies
OFC network is used to cover the long distance while coaxial network is used to cover the short distance. Because OFC network provides the less amount of loss in signal in comparative coaxial network. In OFC network there can be repeaters or splitters.
While in Coaxial Network there can be Amplifiers, Passive Splitters and Tappers. These passive splitters are used to split the signal in two ways for distribution of two different subscribers. While Tap can be used to connect one subscriber and by pass the large signal strength. NODE and Amplifiers require the external DC power.
In coaxial network there can be various kind of noise like amplifier’s noise and passive splitters noise and tap off noise. OFC network maintenance cost is lesser than Coaxial Network Maintenance cost.
Conclusion
HFC network is the combination of fiber network network with coaxial network. In OFC network splicing can take place to splice the two fibers and puts this joint in Joint Box. While in the coaxial network jointers are used to joint the coaxial cable. Also passive splitters and amplifiers are used in coaxial network.
Know More About What Is Optical Fiber Cable
Sir how fiber signal is send to node….which device is being used to convert the rf out of QAM into optical signal?pls elaborate..
You need to use transmitters which convert your RF signal into Optical signal and sends your signal at long distance according to your transmitter’s dbm.