Formation of Frequency-Modulated Signals Using the Direct Digital Synthesis Method

The most important trends of the development of communication and radiolocation systems are the application of higher frequencies and the transition to the use of complex signals for the creation of new advanced radio engineering systems with improved noise immunity. The search for new methods of improving the operation speed and "spectrum purity" of formed oscillations is very important. The purpose of the work is to extend functional capabilities of direct digital synthesizers and digital frequency synthesizers, when using them in radio-electronic systems of radiolocation, navigation and communication. Research methods. While solving the set tasks, the methods of the signal theory, number theory, probability theory and mathematical statistics as well as mathematical modeling, computer simulation and experimental research were used in the work. Results. These direct digital synthesizers allow synthesizing frequency-modulated and phase- manipulated signals and they have extended functional capabilities in comparison with other types of synthesizers. The given direct digital synthesizers can be used in adaptive communication systems, telecommunications, radio-engineering systems for the remote sensing of the ionosphere, in radiolocation and navigation systems.