Design of Function Signal Generator Based on DDFS

Abstract

The system is designed to construct a Function Signal Generator based on Direct Digital Frequency Synthesis Technology (DDFS), in which MCU and FPGA are the key components and necessary peripheral circuits are provided. Its main modules are responsible for the formation of oscillogram, the frequency synthesis, the digital-to-analog transformation, the control of range, and back-stage treatment, the user interface and other necessary modules. MCU controls FPGA to generate the oscillogram and other control words, and the FPGA controls output waveform and frequency synthesis. Amplitude control is realized by 2 DA. Low-pass filter and Transistor push-pull power amplification circuit are used to increase the quality of the output waveform and its loading capacity, and display the signal on the LCD. The system constitutes of 2 DAC and the FPGA, so that realizes the expanded requirements of 1 Hz-1MHz of the four waveform output.