Timeline for Spectral window when FFT is not a power of 2
Current License: CC BY-SA 3.0
16 events
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| Mar 22, 2017 at 19:57 | comment | added | Jason R | MBaz's answer is correct. Also note that for most purposes, the approximately -100 dB dips that you see in the first plot aren't all that different numerically from the -300 dB dips in the second. Both represent really small numbers. In most applications, if you want something to be attenuated by a good amount, you won't notice much of a difference between -100 and -300 dB. | |
| Mar 22, 2017 at 18:06 | vote | accept | Michael R | ||
| Mar 22, 2017 at 16:03 | history | edited | Michael R | CC BY-SA 3.0 |
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| Mar 22, 2017 at 12:55 | answer | added | Olli Niemitalo | timeline score: 1 | |
| S Mar 22, 2017 at 10:27 | history | edited | jojeck♦ | CC BY-SA 3.0 |
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| Mar 22, 2017 at 7:04 | review | Suggested edits | |||
| S Mar 22, 2017 at 10:27 | |||||
| Mar 22, 2017 at 4:42 | answer | added | hotpaw2 | timeline score: 2 | |
| Mar 22, 2017 at 3:56 | answer | added | catraeus | timeline score: 1 | |
| Mar 22, 2017 at 2:36 | comment | added | MBaz | My guess would be that it is a result of the different spectral leakage produced by the varying resolution. Basically, if you align the nulls of the "true" spectrum with your frequency bin centers, you'll get much more pronounced nulls in the spectrum. | |
| Mar 22, 2017 at 2:29 | history | edited | Michael R | CC BY-SA 3.0 |
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| Mar 22, 2017 at 2:27 | comment | added | Michael R | @MBaz Thanks for your comment. I am new to time series, so I was doing this as an exercise to better understand zero padding and the FFT. I really don't understand why the minima in the above spectra would be so different when zero padding to 500 vs. 512. Is this difference due to the length of the time series? | |
| Mar 22, 2017 at 2:03 | review | Close votes | |||
| Mar 22, 2017 at 10:27 | |||||
| Mar 22, 2017 at 1:43 | comment | added | MBaz | Why are you zero-padding at all? My suggestion is to increase the number of true samples of the signal, so that you can get a spectrum with more actual resolution. | |
| Mar 22, 2017 at 1:42 | comment | added | MBaz | Possible duplicate of Why do we say that "zero-padding doesn't really increase frequency resolution" | |
| Mar 22, 2017 at 1:29 | review | First posts | |||
| Mar 22, 2017 at 2:23 | |||||
| Mar 22, 2017 at 1:29 | history | asked | Michael R | CC BY-SA 3.0 |