Before revision: A transponder is typically composed of: an input band-limiting device (an input band-pass filter), an input low-noise amplifier (LNA), designed to amplify the signals received from the Earth station (normally very weak, because of the large distances involved .
After revision: A transponder is typically composed of: an input band-limiting device (an input band-pass filter), an input low-noise amplifier (LNA), designed to amplify the signals received from the Earth station (normally very weak, because of the large distances involved