Goal of this MSc thesis is to study frequently used modulation types of the digital communications world and to make reachable their different constellation sizes for various transmission systems.
It would be beneficial if these modulation types were implemented at a universal device (here: Software-defined Radio - SDR).
Wide aviability of these functions is needed for researches and projects in their laboratories.
My work has been done with two software radio boards USRP B200 of the Ettus ResearchTM Company.
Owner of these devices is the Optical and Microwave Telecommunication Laboratory of our University.
These devices are equipped with an open-soruce software, called GNU Radio Companion (GRC).
Numerous built-in functions can be found in this program, that are used in broadcasting systems.
The main goal of this project was to realize a transmitter-receiver pair, that is able to execute an M-PSK/QAM modulation within rational conditions.
The text will discuss the problems arising from simple GRC block generation, through adaptive constellation allocation to complete realization of a demodulator.
During solution of my task I met several problems, that required some solutions, so the text will include them as well, somewhere in detail or just mentioning them.
Realization of this task definitely requires the QPSK/8PSK and the 16/64QAM parts, so I take particular emphasis to describe them together with their measurements.
The thesis contains a long appendix, which details the implemented GRC functionalities in Python language, for those who want to improve the modules in the future.