The Design Of The Arbitrary Waveform Generator

As a basic source of electronic equipment, the waveform generator has been widely used in communication, measurement, research and teaching. The signal of traditional analog waveform generator is limited, and the output frequency and amplitude is unstable. As the development of direct digital synthesis(DDS), there are some waveform generators based on specific DDS chip with high frequency resolution and amplitude accuracy. The DDS using the combination of FPGA and high-speed DAC compared to DDS-specific, the biggest feature is the waveform data can be updated by the user at any time, in order to achieve arbitrary waveform output. Different types of arbitrary waveform are more widely used in modern electronic communication, and thus demand for arbitrary waveform generator(AWG) is also growing.The main work of this study is designed to achieve the DDS module with arbitrary waveform output, and use high-speed ARM MCU to pass through the user control information on the DDS module, which implements a dual-channel arbitrary waveform generator. The design is unique in dynamic configuration of FPGA with microcontroller, that can save hardware costs while enhancing the system of secrecy. Full use of FPGA high-speed digital signal processing characteristics achieve the AM, FM, ASK, PSK and other digital modulation. FPGA control through an external serial AD, for the high-speed ADC reference voltage, in order to achieve fine-tuning of the output amplitude.With the Summary of development of arbitrary waveform generator, the paper proposes the design of arbitrary waveform generator. Based on that design, the paper describes the hardware design of this system and the signal integrity analysis of high-speed signals. On the basis of the hardware circuit, the paper focuses on the internal FPGA logic design, DDS functions, and implementation of various digital modulation methods. Finally, the system test reports that meet the design requirements of the system.This design implements a dual-channel arbitrary waveform generator with frequency resolution of 1uHz, frequency range of 1uHz to 20MHz and amplitude range of 2mVp-p to 20Vp-p. That can output 32 kinds of fixed waveforms and 2 user-defined waveforms. Each waveform can achieve a variety of digital modulation.