Desenvolvimento de um gerador de ondas arbitrárias utilizando a técnica de síntese digital direta e com recursos de modulação

Abstract

The waveform generator is one of the most important measurements equipment. It provide controllable electrical signals that are used in circuit testing. This device is capable of generating periodic or non-continuous signals, in a continuous or limited way, synchronized and modulated. The common waveform generator has few adjustable parameters and is limited to sine, rectangular, and triangular waveforms. The arbitrary waveform generator (AWG) allows almost a total configuration of the signal, allowing the user to configure a signal point-by-point. In this way, the objective of this work was the development of a low cost AWG that can be used in Educational Institutions’ laboratories. For the construction of the prototype, it was used a Mercurio IV kit that has a FPGA (Field Programmable Gate Array) and the FTDI FT245 chip. The programming of the generator was based on the DDS (Direct Digital Synthesis) technique, where the signal to be synthesized is stored in a memory and an adjustable step counter loads the date of the memory to a DAC. An output stage that allows adjusting the gain and the base line (direct current level) of the generated signal was also developed. The results were satisfactory since the AWG was able to synthesize the required waves, perform analog and digital modulations, and control the gain and offset in the output stage.