IP Headend Introduction
Basically IP headend is a headend that runs on Internet Protocol. In IP headend each device is controlled by IP from one server. In IP headend we receive every signal in IP and gives IP output.
Internet Protocol Address or IP Address is also known as the Domain Name. A domain name is known as your web address or your electronic address. We can not remember so many ip addresses that is why domain name developed. This domain name is known as your website address or your web address in internet industry.
But in Headend we need to remember or write down IP address of all the devices connected to our main server. That is why we allocate series IP address to all the connected devices.
IP Headend Architecture
IP Headend Working
As you can see above in the figure first of all the we receive the signal through coaxial cable into out IF section of the headend. This RF signal now goes into Professional IRDs and Channel Decorders.
These professional IRDs gives the IP output this IP output goes into the Redundancy switch. Channel decoders output that is composite goes into Encoder. This encoder gives the IP output and now this IP output of the encoder goes into the Redundancy Switch.
The output of this redundancy switch that is IP output goes into the Multiplexer this multiplexer gives the IP output that goes into the Modulator. Now modulator modulate the signal and convert the IP input into the RF output.
Professional IRDs Function
We need to tune these IRDs at the proper frequency to receive the channel. If your channel frequency, polarization and symbol rate would be ok then it will be tuned.
Encoders Function
There are different kinds of encoders available in the market Chinese encoders support the 8 channels while other supports the 4 channels per encoder only. We can increase the volume of a particular service by using this encoder.
Multiplexer Function
We use the multiplexer that not only multiplex the streams while this is multipurpose device which also do Filtering, PID remapping and re-encoding. This multiplexer have lot amount of traffic in it and consumes high power. So we use two multiplexer MUX and MUX BKP.
Redundancy Switch Function
This is high traffic switch which is used to automatically switch all the traffic to MUX BKP ,in case if MUX Pri is not working properly. This is GB Port switch.
Modulator Function
Modulator modulate the signal and in the modulator we need to tune different streams at different RF frequency. Thus modulator or QAM Quadrature Amplitude Modulator gives the tuned RF output.
Transmitter Function
Transmitter receive the modulated output and transmit it to long distance to get proper signal strength. This RF signal from the transmitter goes into the STBs.
Now finally we need to manage the signal strength at the user end to get proper services.
This is basic IP Headend Architecture And Working or CATV System Design.
NOTE: We have not used CAS server here.
Thanks for share these helpful information. Please provide some career related information in HITS.
How to Transmit The Signal From QAM Using Wireless Medium Such as Ubiquiti Products.
Pls Share some data on Compression
hi can yu pls share about VOD architecture and Electronic program guide restrictions and bits etc like 64 day schedule and out of band schedule like MHSI