Make your own free website on

...Transponder block diagram...

              This satellite transponder is the regenerative repeater.Like the other configuration,
    it perform the basic amplification and frequency translation funtions.But in this case,the
    received signal is actully demodulated.Therefore,remodulation is necessary to create the
    downlink signal.

              The basic block diagram of a regenarative transponder is shown in figure above.
    The uplink signal, is amplified and frequency translated as before.However,the output is
    then demodulated.The output of the demodulator,of course is the baseband signal.

              A baseband signal refers to the basic information content transmitted on the uplink
    carrier.The baseband signal maybe a voice telephone conversation,a TV signal,or digital data.
    The output of the demodulator,therefore,in the satellite is this baseband signal.Some amplification
    maybe provided.

              Next,The baseband signal is fed to a modulator along with a carrier at the downlink
    frequency.The modulation is usually FM.The ouput of the modulator is a new carrier containing
    the same information.The signal is then amplified,filtered and transmitted over the downlink.