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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14 views

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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846 views

How can create a .wav bar based spectrogram on matlab?

How can I create a bar based spectrogram that updates as a .wav file is playing. This is commonly found in music players. Here is an example below: I am able to display a amplitude/frequency graph ...
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106 views

revert back to stft from abs and phase

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

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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2k 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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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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54 views

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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41 views

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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1answer
56 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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1answer
121 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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1answer
30 views

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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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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479 views

Using MATLAB's Spectrogram Function for Analysis

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

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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4answers
187 views

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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44 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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155 views

What is the value range of log magnitude spectrograms?

I'm quite new to this field and have a probably rather basic question: Is there an upper bound for the values in a log-magnitude spectrogram generated like this: ...
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200 views

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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1answer
42 views

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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1answer
60 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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20 views

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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3answers
245 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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1answer
105 views

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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1answer
864 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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interpret wavelet scalogram

My knowledge of wavelets is less than epsilon. Bear with me. If I have a signal of two well separated sinusoids (15 and 48 Hz) plus some random noise, I can clearly make out the two in a spectrogram (...
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105 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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1answer
118 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
770 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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8k views

Understanding overlapping in STFT

I understand the concept of the STFT. In order to avoid spectral leakage, you use a Hann window that overlaps by 50%. However, the problem that I have, is that the example code online does not account ...
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20 views

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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2answers
392 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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111 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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2answers
1k views

Obtain the frequency response of a time domain chirp signal

I have simulation data in the time domain and I need to represent them in the frequency domain. The data have been obtained time integrating the following equation: $m \ddot{x} + c\dot{x} + kx = A \...
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74 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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58 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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1answer
448 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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242 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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54 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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479 views

How to interpret these MP3 spectrums?

Recently, I found I had this song duplicated in my music library, but when listening to them I noticed one version was of noticeably higher quality than the other despite both claiming to have a ...
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313 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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209 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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34 views

Energy Detection Sensitivity Comparison

In the area of broadband spectrum sensing, there are multiple methods used to detect energy. Two common methods are: Energy detection in the time domain (matlab example) Spectrogram (often defined by ...
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81 views

Frequency contour detection in spectrogram

I have an image of a spectrogram and I wish to detect the tracks/contours of prominent frequencies present in the spectrogram. In the end, I want to be able to get various prominent curves from the ...
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1answer
101 views

Help needed for Matlab Spectrogram plot

I am trying to plot a spectrogram using Matlab. Basically what I need is to have: -time in the X axis -Velocity in Y axis -Intensity is the current (in pico Ampere) Basically, I want to create a ...
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19 views

What features capture the semantics of a sentence from a gien audio?

I have been thinking lately and looking up on what could be the possible features that capture the semantics of an audio and came across MFCC: MFCC features represent phonemes (distinct units of sound)...
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1answer
47 views

Comparing spectra from hyperspectral images

I extracted the mean spectra of regions of interests of different tissues from hyperspectral images. How to compare those spectra by the difference of their reflectance and their spectral behavior (...
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2answers
181 views

What's the theoretical bandwidth?

A radio signal is sampled at $f_{s}=5512$ Hz, and $n=2^{14}=16384$ points are used in the FFT to display it as a spectrogram. The frequency resolution is $\frac{f_{s}}{n}=0.33642578125$ Hz/point, ...
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186 views

Spectrogram of an executable binary [closed]

One of the approaches I have been searching so far is the application of utilizing Neural Network to classify Spectrogram images, which is heavily used in speech recognition. I am conducting an ...
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845 views

how to create a harmonic mask from fundamental frequency?

Using an algorithm that gives the fundamental frequency across time, example https://www.mathworks.com/help/audio/ref/pitch.html (or some other one?) how would I then use that, to create a harmonic ...
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4k views

Converting mel spectrogram to spectrogram

I have a set of songs for which I extracted the STFT (Short-Time Fourier Transform) and used the magnitude spectrum $|S|$ to calculate the mel spectrogram by using a mel filterbank matrix $M$, so $X=\...