SCTE 121 2018

SCTE 121 2018

Test Method for Downstream Bit Error Rate

27,00 €

Détails

The purpose of this test is to measure bit error ratio (BER) of downstream (forward path) broadband telecommunications QAM signals. This procedure will address mainly pre-forward error correction BER results for 64- and 256-QAM.
It is important to rely upon both the pre-FEC and post-FEC BER results. In North America, most 64- and 256-QAM signals incorporate ITU-T J.83 Annex B FEC encoding. It is therefore important to reference the post-FEC result, but extremely dangerous to rely solely upon it. BER suffers from what is commonly known as a "cliff effect" in which the post-FEC BER remains error free up to a point and then begins to rapidly decline. Referring to the pre-FEC BER result can yield insight as to how much margin is available prior to reaching the cliff.

Informations supplémentaires

Auteur Society of Cable Telecommunication Engineers
Edité par SCTE
Type de document Norme
Nombre de pages 14
Remplace SCTE 121 2011,SCTE 121 2006
Mot-clé SCTE 121 2018