這一個“慢”，但簡單和兩維FFT的演示可以從這裡下載（包括源）。



演示生成的一維或二維的輸入信號（256或256×256大小），這是顯示在左邊的位圖（8位灰度調色板）。

信號包含一個中心的矩形脈衝（脈衝大小從2到256）。因為輸入的是真實的，FFT的日常工聯會（）產生偏見的頻譜。如果“重排”被選中，零頻率頻譜的中心轉移到從各自的象限交換數據。複雜的結果顯示在正確的位圖，在可能的方式有四種：模塊，相位，實部或虛部。如果“InvFFT”被選中，逆FFT頻譜，結果是恢復輸入信號應用。然而，恢復輸入信號正確的“重新排序”，已是自由。為了保持傳統的2D信號可以餵從演示Lenna.bmp文件。 （Lenna見下面）。-This "slow" but simple One- and Two-dimensional FFT Demo can be downloaded from here (source included).



The Demo generates a 1D or 2D input signal (with size 256 or 256x256) which is displayed in the left bitmap (8 bit gray palette).

The signal contains a centered rectangular pulse (pulse size from 2 to 256). Since the input is real, the FFT routine ftu() produces biased spectrum. If "Reorder" is checked, the zero frequency is shifted to the center of the spectrum by swapping data from the respective quadrants. The complex result is displayed in the right bitmap in one of four possible modes: Module, Phase, Real part or Imaginary part. If "InvFFT" is checked, an inverse FFT is applied on the spectrum, the result being the recovered input signal. However, to recover the input signal correctly "Reorder" has to be unchecked. In order to keep up with tradition, the 2D signal may be fed from Lenna.bmp file which comes with the Demo. (See about Lenna below).