Fast Fourier Transforms in Matlab

This video demonstrates the use of Matlab do do FFTs of time-history data. A higher res version can be found at http://blanchard.ep.wisc.edu/ These videos were recorded for a course I teach as part of a distance masters degree. See http://mepp.engr.wisc.edu

Category:

Science & Technology

Tags:

• Matlab
• FFT
• Fourier
• Transform

[mahm0015]

Question... How do you go about showing more frequency values versus amplitude. You are only shown the frequency versus amplitude for intervals of 1 HZ. Which part of the code lets you change that? Thanks in advance!

[jakeblanchard]

@mahm0015

The frequencies are determined by the sample rate and the number of samples. You have to change one or both of these to change the frequencies produced by the FFT.

[daDfarSpanTaistheKin]

but why is there no builtin command for obtaining the correct fft ? why call this function as fft if it cannot return the result/answer in correct format.. and make ius mad to foind ways to present it the correct way ? Matlab ois tottaly gay,in providing the correct funcanlity.. ..

matlab shoulkd have a function to correctly outpiut the result so that we are not bogged down on unnecessary things..

[jakeblanchard]

@daDfarSpanTaistheKin

I've often wondered the same thing.

[mahm0015]

@jakeblanchard Thanks Millions for the very quick reply... This was an excellent video by the way.. Saved me tons for time :)... Thanks again very much :)

[daDfarSpanTaistheKin]

at 2:48 the graph shows some values .. in reality what thing priduced the spikes with magnitude of 100 ? i mean how it came int being? also how it is ploted somewhere near 5 why ?

[zientist]

great tutorial!  Thanks

[eeprom01]

good

[steinfletch]

Well structured comprehensive tutorial, good stuff!