Roll-off Or Roll-Off factor Factor In DVB Satellite TV Broadcasting

Roll-off: 

Roll-off: This refers to the roll-off factor (α) of the pulse-shaping filter used in the transmitter. It defines the excess bandwidth beyond the minimum required Nyquist bandwidth. In DVB systems:

• A lower roll-off factor means higher spectral efficiency, allowing more data to be transmitted in a given bandwidth.
• DVB-S2 offers a selection of factors (0.35, 0.25, 0.20), a change from the fixed 0.35 in DVB-S.
• DVB-S2X introduced even lower roll-off factors (e.1.g., 0.05) to further improve efficiency.