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What Is QAM And EDGE QAM And Difference Between Them

qam edge qa difference

Introduction Of QAM

QAM stands for Quadrature Amplitude Modulator. QAM is also known as heart of a Digital Headend. Because for a digital headend all the major process are done in QAM like PID mapping ,scrambling and RF conversion. It is used to modulate the signal so that we can send the signal at long distance by using Transmitters and Amplifiers in field. QAM have IP input and gives RF output. Different RF cards are inserted in QAM to have RF output.

Many people is confused, sometimes we call it QAM and sometimes we call it EDGE QAM. So

what is the difference between QAM and EDGE QAM ?

Or these two terms indicate the same thing?

To avoid these kind of questions below we are going to describe the whole thing.

QAM And EDGE QAM Difference

Before the EDGE QAM cable tv companies were using the QAM which was enough to deliver the services in the field according to the requirement of subscribers. But when the term SDV came then it make the possible to make a EDGE QAM.

New version or upgraded version of QAM can be called as EDGE QAM. Even architecture of both devices are same. But difference is that QAM supports VOD not to SDV (Switched Digital Video) streams. QAM is made to use particular service or specific service.

For example if one QAM is used to navigate the web pages for the modem then for Digital Video Channels we need to use second one. Thus QAM supports VOD.

This situation force us to make EDGE QAM which supports both VOD and SDV. VOD stands for Video On Demand.

SDV is very effective service which consume the less bandwidth. By SDV we can provide best format of video to our subscriber. It works in real time. It provides the services which viewer wants to view. The task is generated by the customer threw the set up box. This task it received by the SDV server and send to the EDGE resource manager. This EDGE resource manager send the query to the EDGE QAM then EDGE QAM respond according to the query.

Then EDGE resource manager sends the information back to the SDV server. Now STB is tuned according to the parameter sent by SDV server to the STB. It makes enable the user to watch what they want.



Above shown in the picture there is Arris D5 Universal EDGE-QAM. It is high density EDGE-QAM. It have multiple GbE inputs. It supports HD , SD , CBR and VBR. It have Graphical User Interface for remote connections. It have good redundancy features.

Vendors of EDGE QAM are


Scientific Atlanta




Thus cable operators need to purchase the QAM according to the requirements of their field.

If we are implementing the EDGE QAM. Then EDGE-QAM needs to communicate between two devices in the network. The session manager is responsible for the communication between STB and SDV or VOD server. Also it respond according to the channel requirement of the viewer.

Whereas Resource Manager define the activity of QAM according to the requirement.


As per above mentioned information EDGE-QAM is the upgraded version of QAM. EDGE-QAM is used for multipurpose. QAM supports VOD not to SDV streams. While EDGE QAM supports both VOD and SDV streams. This is why EDGE-QAM is responsible for more tasks than QAM.

Know More About  Difference Between 64 QAM 128 QAM 256 QAM

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  • Article By :
    Ujjwal Swami is Founder Of Headend INFO. He is a Entrepreneur and working for Cable Industry. He is also working for STB HD, Go For Tricks And Heterochromia Iridum Contact Admin@HeadendINFO.com Whatsapp No. +91 8239222444 (To Join Headend INFO Whatsapp Group Send Request On Above Number)


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