Design Of IF Digitalized System In The Space TT&C

The new generation of space TT&C system tends to be more and more digitalized. And the intermediate frequency(IF) digitalized transmitter and receiver,which based on software radio theory,have become the most important part of the space TT&C system because of its generality,flexibility and openness.Therefore, the research on the IF digitalized system has significant meaning.The technology of IF digitalized transmitter and receiver,which based on the characteristics of space TT&C system,has been discussed in this thesis.Two technical difficulties, doppler-shift and bit synchronization,are researched in detail and the corresponding countermeasure is put forward.In addition,a design scheme of multipurpose IF digitalized transmitter and receiver has been proposed and implemented,which can compact all the signal processing units in respective pieces of FPGA to achieve faster processing speed with smaller volume.The test result shows in the large doppler-shift interference, by setting the host computer software,this IF digitalized transmitter and receiver can modulate and demodulate the IF signal of multi-code rate and multiple modulation mode properly.And the bit error rate is very low with certain SNR,showing an excellent performance.