Questions tagged [spectrogram]

A spectrogram is a time-varying spectral representation (forming an image) that shows how the spectral density of a signal varies with time.

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FM modulation - recovering bits

I'm trying to complete one task: Download some FM modulated signals from page http://www.w1hkj.com/modes/index.htm. Calculate their spectrograms, i.e. short-time Fourier transform. Observe different ...
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How to determine number of filters in filter bank based on spectrogram of audio signal?

I want to do an analysis and than synthesis of audio signal, which is audio of vowel 'a', using Matlab. For this I need to use filter bank(array of band-pass filters). I have drawn four different ...
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31 views

How to find peak frequency in an audio frequency spectrum?

I have a audio file consisting of multiple frequencies, I need to find all the frequency peaks in the frequency spectrum after doing FFT. But the issue is how can I be able to set the threshold line ...
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Spectrum of FM signal?

If a carrier ($f_c$) is FM modulated by a single sine wave ($f_m$), its spectrum is composed of frequencies at $f_c + kf_m$ ($k \in \mathbb{Z}$) whose amplitudes are weighted by $J_n(\beta)$, the $k$-...
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How to apply audio superposition in mel spectrogram domain

Very rusty physicist here. I have two audio spectrograms and I want to work out how to calculate the spectrogram of the superposition of the original waveforms (without having access to the original ...
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revert back to stft from abs and phase

I have the following code on python ...
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44 views

Power Spectral Density Reconstruction

I am from an ML background and I am working on MP3 audio reconstruction and I have managed some amount of spectrogram reconstruction but I have noticed that the higher frequency end of the generated ...
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565 views

Python audio analysis: which spectrogram should I use and why?

I am doing my final project at university: pitch estimation from song recording using convolutional neural network (CNN). I want to retrieve pitches existed in a song recording. For CNN input, I am ...
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Trade-off in sample-rate & FFT-size & Doppler

I've got a stream of digital IQ samples let's say at $F_s = 1 MSPS$ that consist of a narrowband signal, in awgn. Let's say the signal BW is ~ 100Hz. The narrowband signal's center (or base) frequency ...
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Understanding CQT (Constant-Q Transformation) parameters for piano AMR (automatic music recognition) with Librosa Library

I am doing an automatic music recognition project with a deep learning model. For my data preprocessing, I am trying to calculate the Constant Q Transform for Polyphonic 88-key piano audio using ...
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60 views

Questions about MP3 bitrate conversions

I was trying to analyse the lossy compression of MP3 audio files through their Spectrograms and the results were something like this (where the upper is 80Kbps and lower is 128Kbps). It is obvious ...
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Plot Spectrogram and FFT plots from samples collected by Atheros AR9271

I'm entering the world of signal processing, and as one of my first projects I've decided to plot a spectrogram and FFT Plot. The samples comes from an Atheros AR9271. More details can be found here: ...
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How to efficiently apply spectrum sensing algorithm

Lets assume 1 signal (lets call it PPG) that is composed "mostly" of 3 different main frequencies components ($f_1, f_2, f_3$) and their harmonics. Now let's assume we have 16 copies of this ...
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64 views

Determining statistically the bandwidth of a signal from a spectrogram

My question is how to determine the parameters of a signal from a spectrogram statistically. The most important parameters that I am looking for are the lower and higher frequencies of the signal. I ...
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110 views

How does modulation frequency appear in the modulation spectra?

I'm trying to familiarise myself with the concept of modulation spectra that I met in this work. My main question appears in the title: how does the modulation frequency appear in the modulation ...
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26 views

How can I perform sound classification based on spectrograms and waveforms?

I noticed that almost all machine learning enabled sound classification approaches use spectrograms or MFCCs as input for feature extraction. I am new to the area and would like to know if we can also ...
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51 views

spectrogram of a leak in a water pipe

I'm doing a work on the acoustic emission of a leak. I am using a 1.80 m cylindrical tube with water, and the leak is simulated by means of a tap that opens after I have applied negative pressure ...
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How to make spectrogram smooth?

I am quite new in DSP and generating the spectrogram of an audio file. My spectrogram is not smooth and it is showing the quite raw image with pixel values, something like this While I am looking for ...
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what is the relationship between a spectrogram and the uncertainty principle heisenberg? [closed]

what is the relationship between these two things Perhaps more resolution in a spectrogram is equivalent to knowing more the position of the electron and less resolution is knowing the velocity of the ...
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Using MATLAB's Spectrogram Function for Analysis

In the documentation - sepctrogram(). Question 1)s = spectrogram(signal) and ...
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21 views

Fbank back to wav

Here's my problem. I have some wav files. I use the wavs as input to compute the fbanks. Then I want to do some stuff with the fbanks and then I want to recreate a wav file associated to the new fbank....
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Order of operations when creating a spectrogram

Signals noob here! I'm dipping my toes into your world by trying to recreate the Shazam algorithm, and I have a quick practical question: When creating a spectrogram, is it better to take in a whole ...
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Reconstructing audio from a given spectrogram and phase data

I have 2 seperate files called: spectrogram and phases. Spectrogram contains magnitude information of audio and phases contain the phase information of each windowed area. I need to reconstruct the ...
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Interpretation of fft plot

I am trying to understand how to interpret a spectrogram image plot: (1) what does the yellow band and its corresponding color code with a high positive value indicate? There are so many yellow bands ...
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52 views

Faded line in spectrogram for a chirp

I've generated this spectrogram using wavelet convolution. The chirp is generated like so: ...
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How can a CNN account for spectro-temporal constraints in neural data?

What are there the best ways to leverage the unique "geometrical" constraints of spectro-temporal signal representations (architecture, filter shapes, data augmentation, etc.)? For example, ...
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How to remap center frequencies of a mel filter bank?

I'm trying to implement vocal tract length peturbation in python (Vocal Tract Length Perturbation (VTLP) improves speech recognition. Navdeep Jaitly, E. S. Hinton, Published 2013, Computer Science) by ...
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127 views

Does downsampling increase the resolution of frequencies?

I am currently working in MATLAB and had to downsample a .WAV file (I used the downsample function in MATLAB) to 44.1 kHz. However, when I compared the two spectrograms of the original signal vs the ...
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Matlab spectrogram

I have to do 'inverse engineering' with piano sound and find sequence of frequencies in it. I have to use spectrogram() and adjust parameters. I set window length as 512 to see more frequencies and ...
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Spectrogram parameters piano sound

I have to do 'inverse engineering' with piano sound and find sequence of frequencies in it. I have to use spectrogram() and adjust parameters but my problem is that I don't know how. I set window ...
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151 views

log spectral distance interpretation

I am using the log spectral distance (LSD) as a metric to evaluate signals. I have 2 completely different signals pairs I compared. Pair (A,B) : signal A as pretty similar to B. There are only very ...
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How to get spectrogram of an array in MATLAB

So.. I want to make spectrogram out of 4 signals that i need to add in array. When I add them in array, it looks like this s=[x1 x2 x3 x4] or with values: ...
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Can someone help me this db transform applied on melspectogram?

I have read some audio processing codes written in Python : ...
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330 views

How to Find spectral Peaks from 2D array of Spectrogram? [closed]

I have computed a Spectrogram 2D array as : How to develop a spectrogram (2D array) from audio signal? Now, I want to find spectral peaks to find the respective temporal displacement. In python using ...
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1answer
111 views

How many things can they be done with a spectrogram?

I found some things that can be done with a spectrogram. filter frequencies by setting the bins to zero observe what frequencies make up the signal. observe the energy or amplitude of each frequency, ...
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56 views

Why does the griffin lim algorithm work?

the griffin lim algorithm works to reconstruct audio from a magnitude spectrogram, but i don't understand how reusing the same spectrogram every iteration with noise can produce decent sound How from ...
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56 views

Running a sox spectrogram on a bandpass filtered wav file

Let's apply a 400-2000Hz bandpass filter on a respiratory .wav file: sox audio1.wav audio1.bandpass.wav sinc -t 10 400-2000 Now I'd like to generate a ...
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2answers
336 views

How to develop a spectrogram (2D array) from audio signal?

I have developed a spectrogram in Python using Scipy.Signal.Spectrogram. But I need a complete understanding of data. Here I am not asking about plotting and color ...
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91 views

How to get coordinates(x(time),y(frequency)) of spectral peaks from spectrogram?

I have created this spectrogram from a wav file. Please have a look: As it can be observed clearly that my somewhat spectral peaks are visible. I want to get the x = time, y= frequency of these ...
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Calculating the spectrogram of the center of pressure time series in human standing balance

I have some biomechanical data of a few subjects standing on a force plate. The center of pressure along the x and y axes was measured. The total time of measurement was 30s and the sampling frequency ...
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Is mean squared error or absolute error on two spectrograms of two different wav files enough to compare how similar they are?

I've been working on a genetic algorithm to figure out how to play a guitar chord just by listening to it. I have it all working now, but the system I am using to compare how 'similar' a guess is to ...
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164 views

How to get Spectrogram after fft in matlab?

I have many EEG signals which record at 100 Hz. I use FFT on them with fft Matlab toolbox. Now I wanted to get a Spectrogram. As I searched and read a lot, I figure that I should window my signal and ...
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83 views

Discrete and Continuous Signals

I am new to the signals area and have been reading through a lot and have some questions. Suppose I have a saved audio file on my computer, .wav file. I can view the time domain of the signal by ...
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46 views

What is the relation between PCM amplitude values and the values in a Spectrogram?

I am curious to know the relation between the 16-bit amplitude values in the PCM-encoded signal and the values inside the corresponding spectrogram. I am using Scipy reading a 44100-sample rate song: ...
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42 views

Please, help me interpret my Simulink simulation of AM. Why does carrier not appear in the spectogram?

Carrier is 2 * pi * 25, modulating signal is 2 * pi, all the amplitudes are 1s and zero phase. I realized that I could add a sine wave right at the end. I get a carrier in frequency domain, but my ...
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266 views

How can I improve the resolution of a spectrogram of a low-frequency signal with high sampling frequency (Python)?

Imagine you have signals $x_1(t)$ and $x_2(t)$ that contain a limited number of periods of low frequency oscillations and are sampled at 44100Hz (coming from an external source) and you want to obtain ...
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2answers
45 views

Why should one choose the maximum as reference for power-to-decibel conversion?

I have seen that one converts the amplitude to decibels through: $\text{dB(S)}=10 \text{log}_{10} \big(\text{S/ref}\big)$, where $\text{S}$ is the output of a STFT and ref the reference value for the ...
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166 views

Time series in spectrogram() and spectrum()

I'm trying to create an order map for order analysis from my accelerometer data. To do that I want to resample my acceleration data and their time stamps in python. I found ...
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201 views

Why are MATLAB and matplotlib spectrogram value different?

I'm doing a signal processing to put data into my neural network. I noticed a difference between MATLAB and Python ...
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102 views

Frequency and Order maps

I'm new to python and I'm using it to analyse accelerations from an accelerometer ie. vibration analysis. For that I need to plot 2 types of diagrams: 1) Frequency map; frequency and time on the axis ...

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