基于FPGA的示波器插值算法实现

Implementation of oscilloscope interpolating algorithm based on FPGA

由于实时采样率的限制,数字存储示波器在快时基档位工作时采集信号的样点数较少,为了重构信号,必须进行插值。提出了基于FPGA实现硬件插值的方法。介绍了示波器中插值方法的原理,利用MATLAB编程仿真比较了插零值、保持上次值、线性插值以及正弦插值等插值方法在重构正弦波、锯齿波以及方波的优劣势,并设计了插值后的抗混叠滤波器。然后在FPGA中实现了插值结构,并在Modelsim中仿真了相关时序,最后应用到实际示波器平台。测试结果表明,FPGA实现的插值算法满足示波器的要求,设计过程简便易行。

At high sweep rates,only a few samples of the signals can be on digital storage oscilloscope screen.To give the user a reasonable view of the signals and to measure their parameters accurately,interpolation is necessary.The hardware interpolation method based on FPGA is proposed.The principle of interpolation method in oscilloscope is introduced.MATLAB is used to compare the advantages and disadvantages of multiple interpolation methods to resumption of sine waves,sawtooth waves and square waves.The anti-aliasing filter is designed.Then the interpolation structure is implemented in FPGA and the related time series is simulated in Modelsim.Finally applied to the actual oscilloscope platform,the test results show that the interpolation algorithm implemented by FPGA meets the requirements of the oscilloscope.The design process based on MATLAB is very simple and practical.