Direct Digital Synthesizer based on Field Programmable Gate Array

摘要

We present the principle (Chapter 2), implementation (Chapter 3) and test results (Chapter 4) of direct digital synthesizer (DDS) that most modules, i.e. phase accumulator, ROM memory and optional amplitude control module are implemented in a digital Field Programmable Gate Array (FPGA) device. To obtain smooth shape of analog output signals the FPGA device is followed by a digital-to-analog converter (DAC) and low-pass filter (LPF). The developed DDS allows for generating signals with frequency up to 50 MHz and amplitude up to 1 Vpp. The frequency adjustment re.solution is 1.9 kHz, while the amplitude adjustment step equals 61.04 μV. The use of programmable device allows for changing the size of tuning words to adapt the DDS parameters to requirements of particular application.