S.N. Kirillov, P.S. Pokrovskij

The design of modern communication systems focuses on increasing the efficiency and duration of the work of the independent power supply. To solve this problem with the frequency resources shortage such nonlinear modulation as FQPSK and GMSK are designed. In order to create a universal energy-efficient radio transmission unit actual task of uniting in a single software-controlled device schemes of the FQPSK-modulator and GMSK-modulators, with the possibility of continuous tuning between these types of non-linear modulation. The aim of this work is to develop universal software-controlled shaper of non-linear modulated radio signals with controllable coupling between the quadrature components. The scheme of the universal software-controlled shaper of non-linear modulated radio signals allows separation between the quadrature components by means of two parameters. Studies have shown that on the proposed device can be implement spectrally efficient non-linear modulations such as FQPSK and GMSK. In this case methodological error of radio signal generation meets the requirements for space systems and satellite communication. The formulas were obtained for the calculation of the spectral and energy characteristics, and noise immunity of signals with controllable coupling between the quadrature components. This mathematical tool allows us to describe the properties of FQPSK- and GMSK-signals, which simplifies the process of selecting a suitable environment for the current class of radio signals. Studies have shown that the signals developed by the universal shaper is not inferior to immunity and energy corresponding original FQPSK- and GMSK-modulators, as well as benefit from them in terms of-band radiation.