基于FPGA的幅值可调信号发生器设计

Design of amplitude adjustable signal generator based on FPGA

针对信号发生器对输出频率精度高和幅值可调的要求,采用直接数字频率合成(DDS)技术,提出一种基于FP-GA的幅值、频率均可调的、高分辨率、高稳定度的信号发生器设计方案。采用AT89S52单片机为控制器,控制FPGA产生波形的数字信号,结合双数模(D/A)转换器及低通滤波器,最终实现输出信号幅值0～5 V可调,分辨率为10 bits;频率范围1 Hz～10 MHz可调,最小分辨率为1 Hz;频率稳定度优于10-4。信号参数可通过键盘进行设置,并在LCD上输出。由于FPGA的可编程性,易于对系统进行升级和优化。

For the requirements of high frequency accuracy and amplitude adjustability of a signal generator,the direct digital synthesis （DDS） technology is applied in the design of the FPGA-based signal generator. The amplitude and frequency of the output of the signal generator are adjustable,and high resolution and high stability are obtained. MCU AT89S52 is used to control the whole system,and the signal generated by FPGA is output through a double-DAC and a low-pass filter. The amplitude range is 0~5 V with the resolution of 10-bit,the frequency range is 1 Hz-10 MHz with the minimum resolution of 1 Hz,and the frequency stability is better than 10^-4. The parameters of amplitude and frequency can be entered through keyboard and displayed on LCD. Due to the programmability of FPGA, the system is easy to upgrade and optimize.full adder function can be well implemented by using simulation design of Muhisim software.