Signal Generator - Based on Direct Digital Synthesis (DDS)

Welcome,

My name is Jorge Pinto I'm a Portuguese student and i am finalizing the course of informatics engineering and telecommunications at the school: Escola Superior de Tecnologia e Gestão de Lamego.This site, represent the total description of my final project that consist in a signal generator based in DDS.

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This project, consist in develop a signal generator that is capable to produce the three most popular wave types (sine, triangular and square) based on the Direct Digital Synthesis (DDS). The digital component of the DDS system is produced by a microcontroller of ATMEL (ATMEGA32) and the inputs via the front panel or the PC are controlled by another microcontroller (ATMEGA169). The communications between the microcontrollers is made by SPI. The ATMEGA169 used in this project, is embedded in the AVR Butterfly, so the LCD is used to indicate the users choices.

With the ATMEGA32 it's possible having total flexibility of the wave, because we have control of the LUT (Lookup Table), but it produces very low frequencies (until 800Hz). So, to produce high frequencies (until 125Mhz), another output signal was used. This output is controled by a chip of Analog Devices (AD9850).

To convert the digital signal to a analog signal, a 8 bit DAC R2-R was used.

One USB module (DLP-USB232M) was used to connect the signal generator to the PC. So, the second part of the project, consist in develop a software in Java capable to control the signal generator. The software have a draw area where the user can easily create a personalized wave geometry.