Indoor Units (IDU) are part of the ground station for satellite transmission or also for the reception of terrestrial signals. They are the components of a ground segment located inside a building. This unit is better known as a receiver
isdown-converted in the LNB converter to an intermediate frequency
of950 MHz and 2.150 GHz. This intermediate frequency is transmitted via the antenna cable and is the input signal of the Indoor Unit (IDU). In a further mixing, a VHF signal for the television is obtained from the IDU input signal via a further intermediate frequency formation and, after demodulation, the useful signal, for example an FBAS signal
, is obtained. The VHF signal can be fed into the antenna input of the TV, the FBAS signal into theSCART socket
. The LNB converter is located outside the building and belongs to the Outdoor Units (ODU).