Questions tagged [frequency-analysis]
393 questions
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Amplitude associated with a range of frequencies in FFT
The Web Audio API function getByteFrequencyData returns an unsigned byte array containing the frequency data for an audio sample. How can I extract the mean value associated with a range of frequencies? I'm looking for a function of the form
…
user76284
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How would i change this to be in a private void?
How would I change this to go into the private void?
It is currently in the public static void. The main problem is that in the private void it cant read string. I am quite new to programming so please be patient if this is quite easy to do.
import…
user3429626
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Convert time series to frequency domain
I have a fundamental question:
I would like to know, why this time series:
k<-c(4,5,6,2,3,1)
is equal to:
21.0+0.000000i 0.5-6.062178i -1.5-0.866025i 5.0-0.000000i -1.5+0.866025i 0.5+6.062178i
In time series I have a set of points, but what is…
Kaja
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How to find top 10 frequent substring from string databases
Assume I have a txt file, each line represents a string. Is there some efficient way to find out top 10 frequent substrings.
The difficulty is that there are too large size of substring permutation for a given string. Given a N length of string, it…
shijie xu
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FFT frequency analysis seems to get wrong values
I saw lots of posts here regards frequency analysis and seemed to help me a lot,
yet I tried to record my voice and print out the frequency and seems like the values has no relation
to what is recorded, tried to lift my voice pitch up and down to…
Er85
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Word lists for a lot of articles - document-term matrix
I have nearly 150k articles in Turkish. I will use articles for natural language processing research.
I want to store words and frequency of them per article after processing articles.
I'm storing them in RDBS now.
I have 3 tables:
Articles ->…
mumino
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Very narrow FFT window functions?
What are the flat-top window functions that provide the narrowest lobe width?
I'm doing FFT analysis and I need the resulting main lobe of a sine wave to be as narrow as possible but avoiding scalloping loss. I ask for flat-top functions because…
user2464424
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extract color objects using spatial and frequency domain filtering
This is the image I am having. I am trying to extract the yellow stars alone from this image using spatial and frequency domain filters. Can anybody suggest me a good method to do it, that would be robust as well? I am trying to use histogram in…
Lakshmi Narayanan
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Decomposing periodogram to extract key signals
I have a standard periodogram produced from the spectrum function call in the R "stats" package with frequency vs spectral density. The spectral analysis relates to long monthly ocean water level time series data that are composed of many signals…
Phil W
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Adjusting the operating frequency of a module in Verilog
I am creating a fairly complicated module which involves timing analysis of 2 Modules each having their own algorithm, but take in 2 signed numbers as inputs and output a signed number.
I am designing this module for an FPGA in Verilog using Xilinx…
Prashant Vaidyanathan
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FFT guitar tuner application - incorrect frequency
I have been working on a guitar tuner application. I understand that the FFT is a bad choice for this kind of application. However, as deadlines get ever closer, and my original specification submission specified use of this algorithm. So…
Cillian Donlon
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How to get PCM data from recorded sound for Fourier analysis
I've been working on c++ code that will take in sound and output it's core frequency, like a guitar tuner. I can generate my own randomized sine wave and successfully perform the FFT from a text file that is just amplitude vs. time. I just don't…
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processing + bitWrite + arduino
I am working with an Arduino and Processing with the Arduino library.
I get the error "The function bitWrite(byte, int, int) does not exist.";
it seams that processing + Arduino bitWrite function are not working together.
its raised due to this…
skyfly200
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mp3 and m4a frequency analysis
I'm doing some frequency analysis on mp3 files using FMOD's getSpectrum function and other utilities on windows. It was working very well but then I tried to load a file from iTunes which is a .m4a and learned that FMOD doesn't support that format…
Alicia Cano
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An algorithm to detect a certain frequency?
Using Goertzel algorithm I am detecting a certain frequency that goes into the iphone microphone (I use buffer samples).
Its working, but it has many strange stability problems when values are changed. (they are constant at a spectrum app on same…
Curnelious
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