# How to perform FFT on stored digital data [closed]

I have to do FFT in MATLAB on the digital sinusoidal data that is stored in excel. please find the amplitude values of the sine wave discrete signal stored in the Lookup table.

Number of points : 256

Maximum amplitude : 1024

Numbers per row: 1

Numbers are in decimal

512, 525, 537, 550, 562, 575, 587, 600, 612, 624, 636, 649, 661, 673, 684, 696, 708, 719, 731, 742, 753, 764, 775, 786, 796, 807, 817, 827, 837, 846, 856, 865, 874, 883, 891, 900, 908, 916, 923, 931, 938, 945, 951, 957, 964, 969, 975, 980, 985, 990, 994, 998, 1002, 1005, 1009, 1012, 1014, 1016, 1018, 1020, 1022, 1023, 1023, 1024, 1024, 1024, 1023, 1023, 1022, 1020, 1018, 1016, 1014, 1012, 1009, 1005, 1002, 998, 994, 990, 985, 980, 975, 969, 964, 957, 951, 945, 938, 931, 923, 916, 908, 900, 891, 883, 874, 865, 856, 846, 837, 827, 817, 807, 796, 786, 775, 764, 753, 742, 731, 719, 708, 696, 684, 673, 661, 649, 636, 624, 612, 600, 587, 575, 562, 550, 537, 525, 512, 499, 487, 474, 462, 449, 437, 424, 412, 400, 388, 375, 363, 351, 340, 328, 316, 305, 293, 282, 271, 260, 249, 238, 228, 217, 207, 197, 187, 178, 168, 159, 150, 141, 133, 124, 116, 108, 101, 93, 86, 79, 73, 67, 60, 55, 49, 44, 39, 34, 30, 26, 22, 19, 15, 12, 10, 8, 6, 4, 2, 1, 1, 0, 0, 0, 1, 1, 2, 4, 6, 8, 10, 12, 15, 19, 22, 26, 30, 34, 39, 44, 49, 55, 60, 67, 73, 79, 86, 93, 101, 108, 116, 124, 133, 141, 150, 159, 168, 178, 187, 197, 207, 217, 228, 238, 249, 260, 271, 282, 293, 305, 316, 328, 340, 351, 363, 375, 388, 400, 412, 424, 437, 449, 462, 474, 487, 499


I have tried writing code in MATLAB but I am not getting the exact output. lease tell me the coding procedure to obtain FFT.

## closed as unclear what you're asking by Matt L., jojek♦, lennon310, MBaz, ThPFeb 20 '15 at 8:30

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• Why not use fft()? Or are you supposed to write your own implementation of a DFT/FFT? If you just want other users to provide code, then this question is off-topic on this site and will be closed. – Matt L. Feb 19 '15 at 8:04
• What output do you expect and what do you get? – Deve Feb 19 '15 at 8:06
• This might help: dsp.stackexchange.com/questions/20212/… – Rhei Feb 19 '15 at 12:13