PROMAX DOCSIS analyzers are designed to deploy, troubleshoot and maintain DOCSIS 3.0 and DOCSIS 3.1 data over cable networks. DOCSIS 3.1 brings a good number of new technologies to the table which put together become the essence of this new powerful CATV standard. Here you will find these innovative developments as well as their related jargon explained below.

DOCSIS 3.1 extends the Upstream band up to 192 Mhz and the Downstream band up to 1.2 Ghz (optionally up to 1.8 Ghz) with the objective of increasing network capacity.

DOCSIS 3.1 band extension

OFDM modulation

Both Upstream and Downstream DOCSIS 3.1 channels use OFDM RF transmission technique as opposed to SC-QAM (Single Carrier QAM) channels. These means that each channel is actually made up of thousands (2K, 4K or 8K) of narrow band subcarriers, so narrow and close to each other that together look as a unified carrier to the naked eye. This is the same transmission technique used in standards such as DVB-T/T2 or C2.

  • Number of subcarriers: 1900 (2K mode for Upstream), 3800 (4K mode for Upstream or Downstream), 7600 (8K mode for Downstream).
  • Subcarrier spacing in 6 Mhz channels: 25 kHz (4K mode for Upstream, 8K mode for Downstream) or 50 kHz (2K mode for Upstream, 4K mode for Downstream).


OFDM modulation
DOCSIS 3.1 exclusion bands

Exclusion bands: Ensuring compatibility with legacy DOCSIS

The exclusion bands are ranges of subcarriers that are deactivated within a channel for 2 main reasons: To ensure backwards compatibility with legacy DOCSIS channels that may be transmitted in that frequency range, or to avoid using that band because it significantly suffers from strong interferences or noise.