TA0321

www.DataSheet4U.com TA0321 TECHNICAL ARTICLE Lightning protection for LNB supply and control voltage regulator Introduction Communication satellites operate within two frequency bands for TV/Broadband service broadcast signals, C Band and Ku Band. The C Band overall frequency spectrum is 4.0 GHz - 8.0 GHz, while the Ku Band overall frequency spectrum is 10.7 GHz - 18.4 GHz. Within these bands each satellite has a specific uplink and downlink frequency allocation. For example: ■ ■ Ku Band downlink frequency is 10.7 GHz-12.75 GHz and uplink frequency is 17.3 GHz-17.8 GHz. C Band downlink frequency is 3.7 GHz-4.2 GHz and uplink frequency is 5.925 GHz-6.425 GHz To use the frequencies that are available for satellite broadcast as efficiently as possible, and to accommodate an additional number of channels within a given frequency band, the transmission signal can be formatted to be either vertical and horizontal, or circular right-hand and circular left-hand simultaneously per frequency. UPLINK DOWNLINK January 2006 Rev 1 1/12 www.st.com 12 1 What is a Low Noise Block (LNB)? TA0321 1 What is a Low Noise Block (LNB)? An LNB is a low noise block module, placed on the focus of the satellite dish antenna (parabola) that provides the following functions: ● Down conversion of the incoming signal from GHz range to the 910 MHz - 2150 MHz (for Europe) range called “first conversion signal”. This conversion allows the signal to be carried by an inexpensive coaxial cable towards t...