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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

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how to change x axis to find peaks from magnitude spectrum in python

I've loaded an audio file with librosa to plot its magnitude spectrum signal, sr = librosa.load(audio_file, sr=44100) signal_fft = np.fft.fft(signal) magnitude = np.abs(signal_fft) frequency = np.linspace(0, sr,…
joachimpoutaraud
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Using python to convert wav file to csv file before feed the data into FFT for audio spectrum analyzer

I am working on a simple audio spectrum analyzer using FPGA. For the preprocessing part, my idea is to use python to convert wav file to csv file, and then feed the data to a fast fourier transform module. Is it possible to get it work?
Meiyi Zheng
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Note Onset Detection using Spectral Difference

Im fairly new to onset detection. I read some papers about it and know that when working only with the time-domain, it is possible that there will be a large number of false-positives/negatives, and that it is generally advisable to work with either…
user488792
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Display spectrum of region of interest with Rasterio and Geopandas

I believe this is a very simple question, but for some reason I really struggle with finding the way to do that. I have plot a satellite image that has 13 bands and shapefile that located on top of it, using Rasterio and Geopandas as…
Reut
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R: Create New Dataframe Variable Based on List Element Name

I have a list of 11 data frames, the name of each data frame describes its source. Essentially I want to add a "source" column to each data frame in the list which contains the name of the data frame in each cell. This is all so the data can be…
DrBalticYaldie
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Setting range for baseline in R

I am using the baseline package in R and just working through the documentation. Their example code produces the following image. data(milk) bc.irls <- baseline(milk$spectra[1,, drop=FALSE]) plot(bc.irls) In my case, the x ticks should not start…
Matze
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Plotted Spectrum Analysis with FFT/STFT causes artifacts

I'm trying to simply Display a WAV File in it's Frequency Domain using this FFT. I try accomplish this via Short-Time-Fourier-Transform with a set Window Size etc. The output is dealt with by drawing with pixels on a JFrame (the higher the Amplitude…
xKaydy
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Choosing a precise frequency interval for power spectrum

I want to compare the power spectra of the time traces of two random processes but the frequency range returned is different. How is that frequency range chosen and how can I modify it ? More specifically, what I do is the following: from scipy…
3sm1r
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How to import multiple .jdx files from a specific folder in Shiny, then evaluating them using ChemoSpec packages?

I'd like to use a simple Shiny app to upload some spectroscopic data (in .jdx format) from a specific folder and evaluate them using ChemoSpec of readJDX packages. I have prepared the following code for R Shiny, but I still can't evaluate the data…
Eugenio Alladio
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How to produce a detailed spectrogram from Fourier output?

I am developing a little application in Visual Studio 2010 in C# to draw a spectrogram (frequency "heat map"). I have already done the basic things: Cut a rectangular windowed array out of the input signal array Feed that array into FFT, which…
LimeAndConconut
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The last dimension of the extracted Mel spectrum is 4

I am new to speech recognition. I plan to extract the Mel spectrum of the audio data, but I print out img.shape and find that its dimension is (650, 20000, 4), and the last dimension is 4, I don’t know why. Below is my code function. def…
赵若琰
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Python spectrum analyzer

I want to build a Python module receiving FFT data from a receiver (bandwidth from 20 mhz to 6 ghz). My goal is: Estimate noise floor. Detect energy over the noise floor (signal detection). Classify detected signal: Center frequency, low frequency,…
eduardosufan
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Computing LF/HF frequency bands for an R-R array

Assume RR is the array containing the R-R intervals of an ECG (in milliseconds). Which is the correct method for computing the HF and LF frequency bands? I don't get the point, because I find apparently conflicting works that confuse me, i.e.,…
Eleanore
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Butterworth filtering of EEG data in R

I'm very new at R and EEG signalling so please excuse me if the answer to the question is obvious. I'm trying to perform a Butterworth filter to an EEG signal to extract the Alpha band. When I executed the filter, the resulting signal looked very…
Ian Quest
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Audio processing with fft iphone app

Possible Duplicate: AurioTouch & FFT for an instrument tuner I am working on one app in which i need to do the spectrum analysis of the incoming audio sounds. I am new to it only thing i know is that i need to use the FFT. I looked in to the…
Satish
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