Stack Overflow
Stack Overflow

Questions tagged [spectrum]

The frequency domain of a wave-like function.

Spectrum refers to the full range of all frequencies of electromagnetic radiation. Spectrum has since been applied by analogy to topics outside of electromagnetic radiation. For a complete discussion, see the Wikipedia Spectrum article

389 questions
10
votes
4 answers

MP3 bitrate detection through frequency spectrum analysis

Is there any program that detects the bitrate of an MP3? I'm not talking about the effective bitrate that the file has been encoded with, but the real bitrate that can be calculated only by frequency spectrum analysis. For example, if I have an MP3…
eimiar
  • 111
  • 1
  • 1
  • 5
10
votes
1 answer

Using of getSpectrum() in Libgdx library

I know the first thing you are thinking is "look for it in the documentation", however, the documentation is not clear about it. I use the library to get the FFT and I followed this short…
Gabrer
  • 465
  • 5
  • 21
9
votes
3 answers

How to resample/rebin a spectrum?

In Matlab, I frequently compute power spectra using Welch's method (pwelch), which I then display on a log-log plot. The frequencies estimated by pwelch are equally spaced, yet logarithmically spaced points would be more appropriate for the…
nibot
  • 14,428
  • 8
  • 54
  • 58
9
votes
3 answers

How to develop a Spectrum Analyser from a realtime audio?

I am developing an app that get a source audio from mic in realtime, with no file storage. Basically, I use: mRecorder = new…
Víctor Martín
  • 3,352
  • 7
  • 48
  • 94
8
votes
3 answers

Visible spectrum with gnuplot

So I have this kind of data 3.500E2 -0.956862 ... 10.00E2 -1.95941 in a file. If I plot it it looks like this: Now I want the area under the curve filled with the visible spectrum, like this: I already found this forum post, which draws me a…
fsp
  • 515
  • 6
  • 21
7
votes
3 answers

Rhythm detection through analyzing the audio spectrum

I'm building a rhythm-based game, and facing a lot of problems with rhythm-detection. I receive the current spectrum of a playing song. It looks like a float array with 512 floats. 256 for left and right channel representation. FFT is also…
xdegtyarev
  • 135
  • 1
  • 8
7
votes
1 answer

Drawing the WaveForm effect of Siri

I have been trying to understand how to draw Siri's wave effect in iOS and came across this great repository. The final result looks like this : However I am having difficulty understanding what is going on with the code that generates the…
user7404038
7
votes
1 answer

Power spectrum with Cython

I am trying to optimize my code with Cython. It is doing a a power spectrum, not using FFT, because this is what we were told to do in class. I've tried to write to code in Cython, but do not see any difference. Here is my code #! /usr/bin/env…
Daniel Thaagaard Andreasen
  • 7,986
  • 7
  • 31
  • 42
6
votes
1 answer

Harmonics count in a music sample

To determine the richness of a sound, I would like to determine the number of harmonics in a sample of music. For that, I'm using Processing with the Minim library which gives me a full spectrum with a FFT. I'm wondering how to count all the peaks…
LaurentC
  • 87
  • 1
  • 5
6
votes
2 answers

Why numpy fft return incorrect phase information?

I compare phase and amplitude spectrum in Matlab and numpy. I think Matlab work correct, but numpy compute correct amplitude spectrum, but phase spectrum is strange. How i must change python code for correct computing fft by numpy? Matlab: fs =…
Антон Пименов
  • 63
  • 5
6
votes
2 answers

How to read in IRAF multispec spectra?

I have a spectrum in a fits file that I generated with Iraf. The wavelength axis is encoded in the header as: WAT0_001= 'system=multispec' WAT1_001= 'wtype=multispec label=Wavelength units=angstroms' WAT2_001= 'wtype=multispec spec1 = "1 1 2 1.…
kgully
  • 650
  • 7
  • 16
6
votes
2 answers

FFT bin width clarification

I'm developing a spectrum analyzer for the 8bit Atmega32 that outputs onto a LCD display. The maximum sampling frequency is 40kHz, and maximum frequency is hence 20kHz, adhering to fs > 2B. At the moment, I am generating a signal internally, then…
Ospho
  • 2,756
  • 5
  • 26
  • 39
5
votes
1 answer

Bad Spectrum from Android's FFT-Output (Visualiser)?

I have some Kind of Question about FFT (Actually I believe it's more about Androids FFT-Output from Visualizer.getFFT()). I have created a Music-Player with own Library function for Android including lot's of Stuff (like genres, dynamic playlists…
rampage
  • 78
  • 1
  • 5
5
votes
2 answers

Where to begin learning about audio processing?

I've tried looking up how I might go about this for a while now, and maybe I am using the wrong terminology in my searches or it's way too advanced for me. I basically want to be able to analyze audio files in real-time. I know hardly anything about…
Dooms101
  • 492
  • 5
  • 19
5
votes
2 answers

Plotting an IR Spectrum with Gnuplot

I have an infrared spectrum for a compound of interest that I would like to plot, and I have a spectrum.dat file with all of the data points. It is of the form: # X Y 300 100 301 100 302 99 303 70 ... 3999 …
ChemWes
  • 57
  • 2
  • 6
1
2
3
…
25 26