Implementation of function signal generator based on FPGA

This paper designs a sweep signal source based on direct digital frequency synthesis (DDS) technology, realizing arbitrary waveform generation and sweep signal generator circuit. The design integrates the DDS circuit, the control and display circuit of the sweep signal into the FPGA, improving the accuracy, signal-to-noise ratio performance and conversion speed. Compared with the traditional crystal oscillator sweep signal source, this design has the advantages of on-chip integration, small circuit size, strong anti-interference ability, high reliability, etc. In addition, this sweep signal source has two frequency output modes: sweep frequency and point frequency, as well as functions such as frequency measurement and sweep speed control, overcoming the shortcomings of traditional sweep signal sources. The experimental results show that the compression ratio of the ROM table reaches 4: 1. In that ROM only stores 1/4 of the sample value of the sinusoidal periodic signal waveform, and then the FPGA control DAC can be used to output the whole period of the sinusoidal signal, so as to synthesize signals of various waveforms, such as square wave, triangle wave and sine wave. To sum up, this designed sweep signal source has excellent performance and practicability.