基于FPGA的精密信号源设计

Precision Signal Source Design for Speaker Power Test

为了提高扬声器功率试验仪校准的准确性,设计一款基于FPGA的高精度正弦信号发生器。该信号发生器采用直接数字合成技术(DDS),由FPGA最小系统、DAC模块、低通滤波器模块、带通滤波器模块和程控衰减模块组成。该设计利用FPGA的现场可编程性、并行处理的高速性,通过低通滤波器进行平滑处理,然后通过带通滤波器进行谐波消除,以及通过程控衰减电路对输出信号的幅值进行衰减,实现精度高,纯度高,幅值输出灵活的正弦信号发生器。其频率范围1Hz-1.5MHz,幅值范围0-500mV。

In order to improve the accuracy of power tester calibration, a high-precision sinusoidal signal generator based on FPGA is designed. The signal generator uses Direct Digital Synthesis(DDS)and consists of an FPGA minimum system, a DAC module, a low-pass filter module, a bandpass filter module, and a programmable attenuation module. This design utilizes the field programmability of the FPGA and the high speed of parallel processing. It is smoothed by a low-pass filter, then harmonically eliminated by a bandpass filter, and the amplitude of the output signal is attenuated by a process-controlled attenuation circuit. A sinusoidal signal generator with high precision, high purity and flexible amplitude output is realized. Its frequency range is 1 Hz-1.5 MHz, and the amplitude range is 0-500 mV.