Design of GMSK modulated software defined radio for nano-satellites

Abstract

In this paper, the construction of GMSK modulated SDR (Software defined radio) design which could be processed in nano-satellites is discussed. A Gaussian FIR filter which is controllable and has the coefficients arranged with different BT values (0.3, 0.5, 0.7, and 1.0) has been formed. After the filter which works on the Cyclone II FPGA has been transformed into analog signal with the data DAC IC which has been obtained with integrator and DDS structures, it is transmitted to the antenna by being amplified to the desired frequency and power with RF circuits. The clock of 150 MHz has been inputted into the system by the frequency which is augmented by PLL in Cyclone II. The output of 2.3 MHz has been obtained. The electronics circuits of the system have been designed with real circuit models and AWR-VSS which is a RF simulation program and it is also shown that the output of 433 MHz and 100 mW power has been obtained in the simulation.