Aplikace kmitočtových syntetizátorů s přímou digitální syntézou v telekomunikační technice

Abstract

The aim of this work is the design and implementation of a tunable generator based on direct digital synthesis technology and it also include verification of its performance by a measurement. Work refers to the problems associated with creating a continuous analog signal by generating a time-varying digital form of the signal with use of digital to analog conversion. The first theoretical part describes the configuration of the DDS system including phenomena that affect the analog output and consequently the need for the output filtering and its impact on the output spectrum. In the second part of the theory the work deals with general description of signals and modulation in conjunction with the DDS technology. Subsequently, the work gives an overview of the application of DDS circuits across technological fields, including an overview of the present circuit solutions produced mainly from Analog Devices. The proposal itself include the choice of synthesis with particular parameters, the choice of peripheral circuit solutions and design associated with simulation of the output reconstruction filter. The entire process of design and the individual parts are described in detail. The next part deals with the program itself and with equipment needed for the desired functionality of the device. The result design is implemented on a printed circuit board and a verification of its functionality is done by measuring on the oscilloscope at the very end of the work. The outcome of this work is fully functional tunable signal generator with DDS technology suitable for use as an agile and accurate clock source.