线性插值的任意函数发生器及其实现

Implementation of Arbitrary Function Generator(AFG) with Linear Interpolation

在基于DDFS方法的任意函数发生器中,合成波形除了正弦波外,还包含各种非正弦波形。对于合成正弦波形,可以使用插值方法降低波表需求,然而对于非正弦波形,由于波形复杂,一般都采用大波表来存放任意函数波形的波表,目前还少见采用插值方法的产品[1]。然而几种典型波形的仿真显示,对于非正弦周期波形,采用插值方法也可以在一定程度上减少波表的使用从而降低成本。在FPGA上的实现也证明了在基于DDFS技术的任意函数发生器中使用线性插值减少波表的可行性。

The AFGs based on DDFS can synthesize not only the sinusoid waveform, but also all kinds of non-sinusoid waveform. When the sine waveform is synthesized, the interpolation can be used to decrease the requirement of waveform table. But for non-sinusoid waveform, the great waveform table is engaged to store the non-sinusoid waveform data in popular AFC-s. However, the simulation of some typical non-sinusoid waveform showed that the imerpolation can also decrease the waveform requirement to some extent in non-sinusoid synthesizing. The FPGA implememation of AFG with Linear Interpolation also showed it＇s practical.