Editing Low-noise block downconverter (section)

==Optical-fibre LNBs==
LNBs for [[fibre satellite distribution]] systems operate in a similar way to conventional electrical LNBs, except that all four of the sub-bands in the entire K{{sub|u}} band spectrum of 10.70–12.75&nbsp;GHz across two signal [[Polarization (waves)|polarisations]] are simultaneously block-downconverted (as in a quattro LNB). The four sub-bands’ IFs are stacked to create one IF with a range of 0.95–5.45&nbsp;GHz (a bandwidth of 4.5&nbsp;GHz), which is modulated on an optical signal using a [[semiconductor laser]], to send down the fibre cable.

At the receiver, the optical signal is converted back to the traditional electrical signal to "appear" to the receiver as a conventional LNB.<ref>{{cite web |url= http://www.globalinvacom.com/products/fibreopticlnb2.php |title= FibreMDU Optical LNB |publisher= Global Invacom |access-date= January 12, 2010 |archive-date= June 17, 2012 |archive-url= https://web.archive.org/web/20120617185239/http://www.globalinvacom.com/products/fibreopticlnb2.php |url-status= dead }}</ref>