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What Is Digital Headend Or Cable TV Headend

digital headend or cable headend

Introduction  Of  Digital  Headend

Basically a headend is server which receive the signal from the dishes then decodes , multiplex , encodes and then transmit it via modulators.

Traditionally we were using the Analog Headend with limited number of services. Number of channels were increasing day by day but there was no any solution. Then the term came Digital Headend.

A Digital Headend system is a new revolution in cable TV industry. Digital Headend changed the whole phenomenon of cable TV industry by increasing the number of services. A large number of services can be run on a digital headend. Also digital headend system reduces the bandwidth and provide us better pitcher quality. Also digital headend enable us to provide more services rather than channels like Radio Service , SDVVOD , internet and digital phone etc.

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Digital  Headend System  Vs  Analog  Headend System Overview

In 860 Mhz bandwidth the maximum channels which we can deliver are 106. But as we all knows channels are growing continuously and to provide all of these channels via Analog Headend is not possible that is why we need to go for compression techniques to provide maximum number of services to our subscribers.

Digital Headend Diagram

Digital Headend System Block Diagram FREEZING

Digital Headend Working

To understand the working of digital headned we will discuss step by step each device.

Dishes

digital headend dish

We receive the signal from the satellite via satellite dishes into the IF section of the digital headend. These dishes are generally mounted on the floor of headend.  These can be C Band or Ku Band Dishes. Each dish is tuned for different satellite to cover all the channels of that particular satellite.  A RG 11 cable is mostly used for to get the signal from these dishes because of its low resistance.

Splitters

2 way splitter

We need to play multiple channels from one satellite cable which comes threw dishes , that is why we need to use splitters. These splitters cab be active splitters and passive splitters.  These splitters split the RF signal into many output.These splitters cab be 2 way , 4 way , 6 way , 8 way and 16 way etc.

Spliitters have RF input and provides RF output. This RF output goes into the IRDs and Decoders as shown above in the figure.

IRDs

digital headend decorder

 

IRDs are known as Integrated Receiver Decoder. These Professional IRDs have RF input and gives IP output as well as ASI output. The IP output of these IRDs goes into the Video Switch as shown in the figure above.

In Digital Headend we use mulitple IRDs to receive many channels. Each IRD is tuned for particular frequency for a particular satellite. So it decode the channels and provide as IP output.

Decoders

satellite receiver

Decoders are used to decode the channels. Decoder have the RF input and provides composite video signal (Audio Video Signal). This signal goes directly into the encoders as shown in figure.

Decoders can be FTA and PAY too. For PAY channels broadcasters provides their own decoder to decode their channels these decoders are known as PAY decoders.

Encodersencorder digital headend or cabel tv headend

The output of decoders which is composite video signal goes directly into the Encoder as input. Now this encoder encode the channels and provides IP or ASI output. This IP output from this encoder goes into the Video Switch.

There are different kinds of encoders available in the market some them encodes 4 channels and others encode 8 channels simultaneously. Each channel is encoded in a particular multicast IP. We can control the bitrate of channels and volume of channels too by using these encoders.

PSI SI Server

psi si server digital headend equipment

PSI SI server is responsible to generate PSI SI tables. It gives IP output to the Video Switch as shown in figure above. We maintain LCN numbers , EPG , Bouquet and Service Description etc. threw this server. If you want to know more about this then visit  PSI SI Tables

Video Switch

switch for cable tv headend equipment

The IP output of encoders , IRDs and PSI server comes to the Video Switch. This is 48 GB port switch. We can also configure this switch to maintain the Data. Each port is having its dedicated LED showing the status of data. It is also capable for hard reset.  A IP output from this switch goes into the QAM.

QAM

bnsg 9000 QAM

QAM is known as Quadrature Amplitude Modulator. QAM is also known as heart of the Digital Headend because it plays important role in it. The IP output of the Video Switch goes directly into the QAM. Its management port is also connected with Management Switch to receive commands by SMS and CAS.

All the transport streams are configured in the QAM and each Transport Streams are tuned for different frequency. Scrambling is performed inside it. QAM modulate the signal and provides RF output. To understand it more visit  What Is QAM.

Management Switch

24 port management switch

Management can be 24 MB port switch. It is connected with the QAM , CAS server and SMS server to send the commands to QAM. The encoders and IRDs are also connected with this switch to get Graphical User Interface access.

So Management Switch provides a medium to get the access of different devices by the client PC.

CAS Server

cas server digital headend equipment

CAS is known as Conditional Access Server. It is connected with Management Switch as shown in figure. CAS server generates the ECMs which are sent to the QAM. CAS server is integrated wtih SMS Server to send the commands to STBs in the field.

We can directly activate , deactivate and blacklist the STB and can perform OSD (On Screen Display) etc. tasks from the CAS server too for testing purpose.

Know More About  What Is ECM EMM

SMS Server

sms server headend equipment

SMS Server is known as Subscriber Management Server. As its name indicates that it manages the subscriber.

A SMS server is integrated with CAS serer. SMS server sends the commands to CAS Server to perform in field. SMS server is used to Activate , deactivate and blacklist the STBs. It can give the commands for On Screen Display on one stb as well on all the stbs.  It can generate the Bill for subscribers as well for LCOs. So that MSO can charge the their LCOs and then LCOs can charge their subscribes. It is connected to CAS server via Management Switch.

Splitter

splitter

Again a splitter is used after the QAM which works as combiner. All the output of the QAM goes as input to the RF output port of splitter.  Now the input port of splitter works as output. So overall we combines all the output frequencies of the QAM into one RF port. Now this RF port goes into the STB by losing signal level from different splitter.

STB

STB stands for Setup Box. The output of QAM goes into the combiner or splitter where it combines and get loss of signal level then it goes into the STB. The STB have RF input and provides Audio Video Signal or HDMI signal as output. Thus STB decode all the signal which it receive from the Digital Headend.

Digital Headend System Benefits

MPEG-2 Compression Benefit

MPEG-2 compression is a digital format. MPEG-2 compression system records only those part of pictures which are changes while it did not records the repeated pictures.

Thus by excluding the repeated pictures it reduces the bandwidth space. This is how MPEG -2 system works.

One analog channel consumes the 7 Mhz frequency approximately in which by using this MPEG -2 compression system we can use approximately 8 TV channels. So we provides maximum data in limited bandwidth. By using this technique we can provide 700 services to our subscribers in 550Mhz bandwidth.

DOLBY Or Stereo Sound Benefit

Traditional analog headend does not support the stereo or dolby sound while digital headend supports the stereo or dolby sound also voice quality is improved in mpeg – 4 compression.

Additional Services

There are many additional services which are provided by the digital headend. These services are

Video On Demand

Radio Services

EPG

Internet service

SDV

etc.

These are the additional services provided by the digital headend.

This is all about the Digital Headend System.

   Know  More  About    IP  Headend  Architecture  And  Working

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Comments

  1. B.Jalander Reddy says:

    my network runing anloge chanels now upgrad todigital control room how much cost of systam

    1. Ujjwal Swami says:

      that depends on how much number of services you are providing and vendor also.

  2. Mrs.molly Fernandes says:

    It’s really interesting to know abut digital I am from Goa so very shortly we r going for digital headend

  3. Vinay mishra says:

    Very shortly and nicely describe

  4. Raj Poonia says:

    What is the price of digital headends of different sarvices

    1. Ujjwal Swami says:

      Digital headend price is approx. 12 lakh for 200 channels in which 64 will be pay channels…also cost depends upon MAKE.

  5. satya kashyap says:

    great info sharing…thanks ujjwal

  6. PRAMOD KUMAR GUPTA says:

    i am cable opretor

  7. md.nayme says:

    sir,
    our 98 channel analog hedean running.now we are set up 128 channel digital heden,but we cannot know how much instrument or expend total cost.please you can send me information.

    your Best regard
    md.nayme
    nirnayme@gmail.com

    1. Ujjwal Swami says:

      Digital Headend is totally different from Analog Headend…only transmitters can be used from your Analog Headend and your modulators will not be applicable for Digital Headend. For 128 channel setup you can use equipments of Gospell Company which contains 1 Gospell QAM (One Card Only) , Gospell PSI Server and Gospell CAS Server, Gospell Encorders, SMS Server, Data & Management switchs. Thus Gospell equipements will be usable for you if you dont want to increase your Headend Cost.

  8. I want to install MPEG 2 Digital Headend with 50 Pay Channels and 50 FTA Channels,
    I will be using Insat 2 e, Asiasat 2 and 3s , Intelsat 17 for the FTA feed.

    What are the Devices used and what will be the Price ?

    Gautam Basneth

    1. Ujjwal Swami says:

      Gautam we will let you know about digital headend devices and its prices for that visit our Contact us page and make a contact to us…thanks

    2. gajendra says:

      Your hedin prise

  9. Thomas D Feely says:

    This is a great website Ujjwal… I’ve been involved with this technology for 30 years now… about 10 years for the old NTSC Analog and 20 years for ATSC Digital… The article mentions 7 MHz channel bandwidth (Consumes 7MHz) I’m not aware of that? PAL uses 8 MHz and ATSC uses 6 MHz…

  10. razi ahmed says:

    very interesting to get basics of digital headened

  11. K. K. Sharma says:

    I want to install MPEG 2/4 Digital Headend with50 HD Channel, 80 Pay Channels and 200 FTA Channels,
    What are the Devices used and what will be the Price ?
    K. K. Sharma

    1. Ujjwal Swami says:

      well cost depends upon the MAKE…to get exact details for costing contact us on our whatsapp number that is mentioned in our our contact us page or provide us your Email ID Thanks

  12. Chandramohanthalla says:

    sir,
    our 42 channel analog hedean running.now we are set up 70 channel digital heden,but we cannot know how much instrument or expend total cost.please you can send me information.
    your Best regard

    1. Ujjwal Swami says:

      200 channels setup costs you arround 12 lakh INR in which 64 will be pay channels rest will be FTA.

  13. Manish mohan says:

    Sir pls tell me only for FTA headend cost . I want no pay channel on my network

    1. Ujjwal Swami says:

      It will cost you near about 8 LAC and there will be 136 FTA channels.

  14. Devendra singh Parmar says:

    Sir 200 channels setup costs you arround 12 lakh INR in which 64 will be pay channels rest will be FTA. Bich company setup Box price . Monthly rental

    1. Ujjwal Swami says:

      For more detail contact us

      whatsapp
      +91 8239222444

      or

      Admin@headendinfo.com

  15. Subhash choudhury says:

    Sir HD channal setup price how much

  16. Munavvar Ali says:

    Munavvar Ali from Delhi
    Sir I want setup your digital cable tv network in our area. Please send me full detail & cost.
    My contact: 91 9811566694 whatsapp number.

    1. Ujjwal Swami says:

      approximately 12 lakh for 200 channels in which 64 pay and rest are FTA channels

      1. Munavvar Ali says:

        Sir receive your mail & thanks for
        reply. 200 chenals in your setup include 64 pay chenales. Please clear 64 pay chenals licence include in this cost.
        Please send your address and contact person Name & contact Numbers.
        Thanks
        Munavvar Ali
        Chauhan Bangar
        New Delhi-110053
        Con: 9811566694

  17. Prince Bohra says:

    Sir
    I am running digital headend of Channel Master and also having CAS, SMS etc bt i am facing a problem of lipsing issue. What can be the causes of this??
    I am trying to resolve from last 3 months.. Can u tell me the causes of this prob??

    1. Ujjwal Swami says:

      follow the steps to findout issue,
      (1) reboot the decoder then check
      (2) reboot the encoder then check
      (3) reset the encoder and reconfigure it then check
      (4) replace the encoder then check

  18. Arvind says:

    thanku so much sir for sharing HE info materials/book

  19. Arvind says:

    Hii just i purchased HEADEND INFO book. it is really superb book for set up Digital HE…thnku so much ujjwal sir for publishing.

  20. Rajnish Saikia says:

    Sir,, Mera Ghar assam main Hain aur main last 20years sa cable ka business main hu aur Mera area rural main Hain. Lakin job sa yeh digital hua hai tab say Mera business bondh ho gaya kiyoki Mera area sa town 30km Hain aur digital ke liya overground cable sa khisna sa aprox 4lakh ka expnd ho raha Hain lakin risk bhj bohut hai maintaince ka. issiliya khud ka pehle jaisa analog ki tarah hi mini digital control room chalana sahta hu lakin isska bare main kisiko jankari nahi hain. Pls mujha botayanga Kiya iss tarah ka min chenel ka digital control room ho sakta Hain kiya?
    Pehle Mera control room 60 Chennal ka Tha aur 300 hudred consumer Tha aur uss sa Mera aur 2employee ka Ghar Aram saal jata Tha lakin Abhi kahisa support nahi milna ka wajah sa bondh korna por raha Hain. Pls help and inform us if possible. Tnks (Rajnish)

Comments

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