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8 views

Pesq numbers and clean speech comparison to processed speech

I am trying to evaluate my processed speech for my DSP project. My project is an implementation of an MMSE algorithm proposed by Y.Ephraim and D. Malah, "Speech Enhancement Using a Minimum Mean Square ...
0
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2answers
45 views

'A priori' and 'a posteriori' SNR

I am reading this paper about speech enhancement using a minimum mean square error short time spectral amplitude estimator for our speech enhancement project. Basically in the paper they mix a clean ...
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0answers
23 views

Writing spectogram code to analyze discrete signal [duplicate]

i am new here and i have a trouble about matlab and analyzing a signal.I need to write a code to display the spectrogram of a discrete-time signal but of course without using ...
2
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0answers
25 views

Aliasing in the Short time Fourier Transform of a pulse

When attempting to take the Short Time Fourier Transform of a pulse, at the end of the pulse I'm running into problems. The signal looks like this at the end (it is a simple $sin^2$ pulse envelope, ...
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0answers
28 views

Mind helping me understand what this matlab code is doing? is this a PSD? or FFT?

I'm trying to learn how to get a useful frequency response of a single plucked string on a guitar. I have some old code that I'm working off of... It works in that i get a spectral response, but i ...
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1answer
39 views

STFT: why overlapping the window?

For STFT, we impose window of certain size onto the original signal, then we perform fft on each window. The uncertanty about frequency and time is determined by the width of the window, however, I ...
0
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1answer
35 views

modified Bessel function for Speech enhancement Using MMSE in matlab

I am trying to implement an algorithm proposed in an old research paper by Ephraim and Malah for my DSP course project. I hope someone can help me with this difficult question. For the clean signal ...
0
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0answers
13 views

Short Time Fourier, What happen when window is outside the sample points

I am trying to compute STFT on the following signals..... such that they have 15 cycles of (1/50) second sine wave, with Fs=10000. The algorithm for STFT I am using is :STFT algorithm Then I set ...
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1answer
55 views

Variance of white noise and the STFT

I hope someone can help me understand the meaning of variance in this case. I am reading an old research paper by Ephraim and Malah (for my DSP project) and it says: Knowing that $D_k$ is the FFT ...
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0answers
14 views

Definition of Cohen's class

The Cohen's class is defined as a class of time-frequency quadratic energy distributions which are covariant by translations in time and in frequency. Can please someone explain why the invariance by ...
0
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0answers
19 views

Band-pass filtering on whole signal or overlapping chunks?

I am working with a signal acquired by a pulse oximeter, i.e. a device that records the change of light intensity reflected by a specific tissue depending on its blood perfusion. Since I am interest ...
0
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1answer
39 views

Interpreting magnitude of DFT results

I'm working on creating a simple program to render spectrograms like this one. In this plot, the X-axis is time, the Y-axis is frequency, and the color represents the magnitude of the DFT at that ...
-1
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2answers
74 views

Implementing Short Time Fourier Tranform

I have a 512 sample frame, lets call it X. The frame is further divided into four sub-frames of 128 samples each. Each of these sub-frames have a different ...
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0answers
52 views

Frequency and time marginals of STFT and Wigner-Ville Distribution

I want to compare time and frequency marginals of Wigner-Ville distribution and STFT. I can calculate WVD's marginals by simple sum operation since WVD is real. But I could not figure out how to deal ...
-1
votes
1answer
94 views

how to read full input signal with STFT in matlab

Please help! I am trying to figure out why in the code i have below my input signal is being cropped but in the code I have a full signal created. The white noise created is 5000 samples for the right ...
1
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1answer
132 views

How to get Envelope of Audio Signal

I am having a problem understanding how the author gets the onset envelope of an audio song in this paper. The entire section in question has been quoted below: First the input sound is resampled ...
0
votes
1answer
274 views

Computing narrowband spectrograms using MATLAB [closed]

I'm having an assignment of computing narrowband spectrograms using MATLAB. And I totally have no idea about the code. Can someone help me writing the code and explaining what's going on to me. Lots ...
0
votes
2answers
119 views

Audio compression with STFT

Let STFT[frame, freqbin] be the short-time Fourier transform of some audio data. (here frame is the index in time, and ...
0
votes
1answer
32 views

Matrix form of STFT

IS there a Matrix form of the STFT that could be applied to a signal directly, as in the case of DFT? We know the matrix structure of the DFT Matrix. Can we derive that somehow for a STFT Transform? ...
0
votes
1answer
62 views

How to obtain the Spectrogram of a signal

I am trying to use Matlab to compute the spectrogram of a signal but I can't seem to figure out how Matlab computes the spectrogram.Consider the case where I have a ...
1
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0answers
41 views

Frequency contour cross-correlation

I'm trying to segment (or extract) different calls from a spectrogram. My current method, calculates a threshold value (variance) and then using RMS can detect voiced/unvoiced signals: $$ Thres = (1 ...
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0answers
39 views

Time of sound-signal

Let's say I have a sound file, I then compute the Spectrogram and segment each part of it. Assume that it is a recording of someone saying the word "Hello" and therefore, each piece is given like so: ...
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0answers
44 views

Calculating hertz / kHz

Over the past few weeks, I have been working on a problem of segmenting an audio file containing some bat samples. I have now successfully come up with a moderate algorithm to do this. I am trying ...
-1
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1answer
46 views

Which FIR filter should I choose?

If I have the following spectrogram: And only wanted to have the signals that are in a particular frequency range (2627 - 3939htz).. Can I run a FIR filter to only allow these signals through, and ...
-1
votes
2answers
90 views

Suggested algorithms for detecting voiced / unvoiced signals [duplicate]

Right. I'm trying to understand the concepts for determining where the signal contains voiced and unvoiced parts. I have created a spectrogram (STFT) of a signal and I'm trying to separate from ...
-1
votes
1answer
95 views

STFT Time Variance - Threshold

This is a follow up question to: Segment/Idenfication of signal from a spectrogram My main goal is to identify (segment) all of the calls from a given signal. The signal looks like the following ...
2
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0answers
72 views

Segment/Idenfication of signal from a spectrogram

I have the following Spectrogram of a signal: Essentially, in this signal, I know there is one point of interest (between 60-80) and between the the particular frequencies. I could, potentially ...
0
votes
2answers
141 views

Normalizing a spectrogram or a pitch class profile

I am developing a chord recognition program using neural networks.I need to normalize the spectrogram or my pitch class profile to provide inputs for the neural network. The pitch class profile ...
0
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0answers
61 views

STFT - Stride the windows?

In matplotlib's spectrogram function, this is how they "seperate and overlap windows": result = stride_windows(x, NFFT, noverlap, axis=0) What this is doing: ...
1
vote
1answer
249 views

PSD - Is this formula correct?

Trying to understand whether or not I am calculating the PSD correctly. Below is the equation that I am using: $$ PSD_{rms}(f_{m} = m \cdot f_{res}) = \frac{PS_{rms} }{ENBW} = \frac{2 \cdot \left | ...
2
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1answer
89 views

PSD - Correct Formula for removing Noise

Ok, so finally some things are making sense. I'm trying to scale the results, which I have done by the following equation: $$ PS_{rms} = \frac{2 \cdot \left |y ...
1
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2answers
67 views

STFT - Putting it all together

I'm currently reading this paper: http://www.rssd.esa.int/SP/LISAPATHFINDER/docs/Data_Analysis/GH_FFT.pdf On page 21, it has a section called "Putting it all together", it states the following ...
0
votes
1answer
45 views

phenomenon when window size for STFT is too short

Hi I was researching on STFT when I encountered this slide online I don't understand the points, Can anyone explain them? Thanks in advance.
2
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1answer
199 views

PSD - Spectrum analysis

Could someone tell me where it is that I might be going wrong with the following problem? Ok, so I'm computing a spectrogram, and, trying to return the PDS of the signal (to show where the signal ...
0
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1answer
80 views

Inverse Short time fourier transform

I am I am working with 'wav' files in audio signal processing. I am able to find out STFT by using the function " spectrogram(file name, window length). Now I want to apply Inverse Short time fourier ...
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1answer
1k views

Power Spectral Density estimate (PSD)

I'm trying to understand PSD, and, it's functions. So far I have carried out the following: Segmented a signal with NFFT = 256 and ...
0
votes
1answer
71 views

filter bank of gabor filters with different frequencies and orientations

I was reading a paper which uses a filter bank of gabor filters with different frequencies and orientations. However, I often see the construction of a filter bank of gabor filters with different ...
1
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1answer
61 views

How to find the Freqs bins

Ok, so I'm kind of moving forward with implementing the STFT. I realise that I was taking the entire FFT and not the first half. The problem that I'm having now is, understanding how to get the Freq ...
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3answers
109 views

Relationship between windowed fourier transform and wavelet transform

I was reading on windowed fourier transform and wavelet transform, and i was thinking that the windowed fourier transform is a subset of wavelet transform. Is that true?
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votes
2answers
108 views

STFT - DFT size of the bins

Having some trouble understanding this concept, really could do with some advice. I want my STFT to have the following parameters: NFFT = 256 ...
1
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2answers
116 views

STFT - Plotting is not a true representation

I might be going crazy here. Following my question: here I did some thinking and probably understood that my STFT algorithm was not performing correctly. I followed this algorithm: -> Get 256 of ...
3
votes
0answers
120 views

Why are the frequencies associated with the STFT bins not representative of the energy?

I'm experimenting with a 30 Hz sine wave and I want to extract the frequencies of this, and have implemented the algorithm to do so. This gives a correct reading, well, gives 29 Hz. I'm now wanting ...
1
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2answers
148 views

Analyse audio/music frequencies without STFT, at 1/f temporal resolution, using probe phasors at logarithmically-spaced frequencies, O(N log N)?

First, some background: The STFT is the best general-purpose tool I know of for analysing a (musical or other) signal into its component frequencies. For many purposes the STFT works fine, but there ...
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votes
2answers
195 views

Spectrogram - Am I missing something?

I have the following signal: I'm trying to compute a Spectrogram algorithm, but, don't think I'm doing it right.. I have computed the following: 1) STFT (size 256 with an overlap of 128) 2) ...
1
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3answers
109 views

Will the resulting spectrogram from this algorithm be 1D or 2D?

I'm implementing a spectrogram algorithm and I get the basic concepts, however, I'm struggling with something. Let's say I have a 1D vector: ...
2
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3answers
1k views

Choosing the right overlap for a window function

On Wikipedia there is quite a list of window functions. However, when you are doing a lot of STFTs, you often have to have some overlap to get better results. Generally an overlap factor of 2 (i.e., ...
1
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2answers
412 views

Zero-padding in STFT

I a recent topic, it has been told that zero-padding in the STFT can improve it, and avoid some circular convolution related things. Here is my Python code for STFT : ...
3
votes
3answers
410 views

Filtering with STFT

I have sucessfully implemented a STFT (+inverseSTFT with perfect reconstruction of original signal, with overlap add, etc.) in order to work on audio files. Using this STFT / iSTFT framework, I have ...
0
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3answers
195 views

importance of symmetric windows for STFT for practical applications

I am wondering why is the linear phase property of filters with symmetric coefficients important for some practical applications of short time fourier transform, such as image processing? I have read ...
1
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2answers
389 views

Discretized CWT vs. DWT vs. FWT vs. MRA

By reading some books about wavelets, it seems that Discretized CWT is not the same thing as DWT. Can we give a classification of Discretized CWT vs DWT vs FWT etc. ? A few remarks : All I read ...