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Questions tagged [signal-analysis]

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0answers
73 views

Distinguish between chords and single notes

I am implementing a pitch detection system where I detect pitch in single notes (guitar). I recently found this library, that detects chords in an audio signal. When there are chords in the signal, ...
2
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0answers
79 views

Is there a way to extract the difference between the 2 signals? Fitting?

I'm very new to signal processing and have been struggling this far. I have a device that measures the signal due to the magnetization of iron particles. In order to calculate the response of the ...
2
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0answers
205 views

Help detecting target in pulsed radar signal

This signal is from the Pasternack $2.4\textrm{ GHz}$ development kit. The saved signal appears to be the pulsed waveform. It is sampled at $20\textrm{ kHz}$ for $4130$ points. I recorded a ...
2
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0answers
150 views

Vibration signal analysis of non-stationary movement

my task is to develop a condition monitoring system of a machine module. For that I am using the vibration sensors placed on the machine housing. I want to focus on only one module of the machine, a ...
2
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0answers
242 views

Connections between quantum field theory and signal processing

I've been working with quantum field theory on the basis of it being a stochastic signal processing formalism for a number of years. The projection to fourier components within the forward light-cone ...
2
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3answers
1k views

How do you save/convert an image to be in the frequency domain?

Quick Note: I don't believe this is a subjective question... however if it is I will gladly modify to be more objective In ImageJ, if I take the FFT of an image, how can I save this new frequency ...
2
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1answer
294 views

How to make sense of audio file's $\textrm{dBFS}$?

I'm trying to build a song visualizer using the FFT method. When I analyze the audio, I get the $\textrm{dBFS}$ value for each frequency range. From my understanding, $\textrm{dBFS}$ is in the range ...
2
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2answers
129 views

How to properly time-shift a function in relation to another function

I'm stuck on a time-variance question in my homework and I think it has something to do with my understanding of how time shifting functions works. The problem asks to determine whether the system ...
2
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0answers
282 views

Is GNU Radio a good choice still? [closed]

I'm a newbie at DSP. I am starting a hobbyist project where I plan to monitor 100's of wildlife radio collar frequencies (at my job) and record how many "beeps" per minute are received. My software ...
2
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0answers
37 views

how to design wavelets from splines

Can any one tell me how to design wavelets from splines using matlab. whether we can make wavelets from higher order splines or only with B splines
2
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0answers
483 views

Peak detection techniques

I'm using a cell-averaging constant false-alarm rate (CA-CFAR) detector to detect peaks like the first one in the following plot: The magenta line is the adaptive threshold, which is the local ...
2
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3answers
4k views

Interpreting the FFT results of a structural vibration problem

System: Cantilever beam type models, with an accelerometer on the end. The beam base is excited at various frequencies in harmonic fashion on a shake table. This results in vibration in the beam. The ...
2
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2answers
89 views

Any basic paper on biomedical signal processing to practise with?

I am quite interested in biomedical signal processing and I am looking for some biomedical signal processing papers in order to reproduce the results that they obtained. The idea is to redo what they ...
2
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0answers
860 views

Analyzing accelerometer data: appropriate use of rotation matrices?

I'm working on a project in which a rod is attached at one end to a rotating shaft. So, as the shaft rotates from 0 to ~100 degrees back-and-forth (in the xy plane), so does the rod. I mounted a 3-...
2
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0answers
44 views

Signal conjugation detected on RF recording samples, why?

I collected spread spectrum signals at 400 MHz at low elevation angles using Software Defined Radio complex sampling over the seasons. I noticed that over watery, icy surfaces, the RF samples are ...
2
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0answers
38 views

Determining the point in a temporal signal when a periodic behavior begins to occur

I'm a newcomer to digital signal processing, so I'm looking for some general advice and direction on this problem I have. I have a signal like that shown below. Starting around x=40000, you can see a ...
2
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0answers
714 views

Extracting the phase of a jittering sine wave using python

The background: I conducted an experiment where I rotated an object (with three-fold symmetry) many times and recorded the projection of the object. I should be able to tomographically reconstruct ...
2
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0answers
147 views

Can ICA be applied to solve BSS problem in frequency domain?

I'm recently doing research on EMI, and I want to seperate the mixing signals. However, the data given is in frequency domain. As I have used ICA to solve blind source separation problem in time ...
2
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0answers
248 views

Is there any problem with my FFT method?

I am trying to analysis a system by Fourier Transform. my system has 3 dominant modes. (1,0.05) (0.51,0.01),(0.46,0.01) the pairs are defined as (freq,damping_ratio) I've got those result with ...
2
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0answers
1k views

Calculation of the correlation of two sinusoidals

First of all I apologize for the long question. I am working with a 3-axis accelerometer and a 3-axis gyroscope and I need to calculate the correlation between the different signals (acceleration in x,...
2
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0answers
111 views

Complex Cepstral Transform and Audio Watermarking

I am doing research in audio watermarking and have come across the paper that uses the complex transform to embed the watermark in order to improve the robustness and inaudibility of the embedded ...
2
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0answers
167 views

How much is the chance for a pure mathematician (geometer) to get a postdoc in imaging if he switches fields after Ph.D. and apply for one? [closed]

Before I start my question, I should probably mention that this question might not be the right question to ask here, but I tried academiabeta, and stackoverflow, but without getting any to-the-point ...
2
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2answers
2k views

Performing a deconvolution

So I have the following data: ...
2
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0answers
44 views

Compare luminosity beetween groups of images

We have a set of images which are immunofluorescence stainings of mice brain slices. These image show the expression level of a marked protein. We have two groups of mice, which underwent behavioral ...
2
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0answers
115 views

Voice sample prediction scheme

I have some telephone voice audio with occasional "blips" in the audio. The blips appear to come from an IP link buried in the PSTN (this is a conceptual explanation, so don't worry about things like ...
2
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2answers
98 views

Signals - question due to sampling

I don't have an idea how to start it. Help pls :) $$m = z(t) + \frac{\operatorname{Sa}(t-T)}{4}$$ We have some signal $z(t)=\left(\operatorname{Sa}(\frac{t}{T})\right)^2$. How often the m signal ...
2
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1answer
848 views

How to find phase values on precise pixel locations of a given Image? [closed]

I have computed magnitude and phase spectrum of cameraman Gray scale image using fft function. Here, we get magnitude and phase spectrum of the whole image. .Please see the reconstruction of image ...
1
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2answers
124 views

Accessing Maximum Value from a Singular Value Decomposed Matrix

I have read few image enhancement papers, where an image is enhanced in transformed domain using either DCT (discrete cosine transform) or DWT (discrete wavelet transform) with SVD (singular value ...
1
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3answers
3k views

Hartley Transform vs Fourier Transform

Can you explain to me in what way Hartley Transform differs from Fourier Transform? Is it even used today or is it some mostly forgotten, obsolete archaic thing? Please don't use equations - I dont ...
1
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1answer
314 views

How to learn MUSIC algorithm?

I was actually preparing for my semester project and decided to take up Frequecncy estimation.I ll directly come to the point that I want to know how should I learn MUSIC algorithm. How do I start it? ...
1
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3answers
148 views

Demonstrate that $x(t)$ and $\hat{x}(t)$ are orthogonal

I have to demonstrate that a function $x(t)$ and his Hilbert's transform are orthogonal, it is said: $$\int^{\infty}_{-\infty} x(t) \cdot \hat{x}(t) dt = 0$$ I have tried the exercise using Parseval'...
1
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3answers
581 views

Extrapolation after taking inverse Fourier transform

Suppose I have 2000 point(time series) signal and I take 512 point FFT, after this some operation is done in frequency domain. Now if I take IFFT to get 512 points in time domain, Is there a way to ...
1
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2answers
82 views

What is this theorem in this formula?

I just read a paper yesterday and there is confusion: I want to know what is reconstruction fidelity term and the theorem of changing the formula from upper to lower one. Is this theorm from ...
1
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2answers
4k views

What is the practical meaning of the variance, covariance, mean value?

What is the practical meaning of variance, covariance and mean for a signal?
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3answers
253 views

Isolate recurrent pattern vs. evolving background sound

Here is a sound example for what follows. Let's assume we have a signal $$s(t) = r(t) + e(t)$$ where: $r(t)$ is a signal which is recurrent with a given period, i.e. in my example $r(t) = $ the ...
1
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2answers
64 views

Can a 1-dimensional signal be in a domain other than the time or frequency domain?

In signal processing I have only heard of signals being in the "Time" domain or in the "Frequency" domain, but are there situations where a signal is not in either of these? If so, what are these ...
1
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1answer
337 views

Practical book in C [duplicate]

Is there any practical “go to” book that demonstrates the main dsp methods for time series written in C for practical applications? (Doesn’t have to be for hardware, but for any raw data such as ...
1
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4answers
1k views

Why does the frequency in the DFT have to be an integer?

I don't know why the result of DFT and FFT in MATLAB like below images.. fs=128; t=0:1/fs:1-1/fs; x=cos(2*pi*3.5*t); X=fft(x); N=length(x); n=0:N-1; f=fs*n/N; plot(f,abs(X)/N); If I set the ...
1
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3answers
2k views

Signals and systems : why do we study causal signals?

Till now I have read that causal signals are right sided and anti-causal, left sided. Why did we need to classify a signal with respect to its position? What is it's physical interpretation? ...
1
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3answers
3k views

What are the advantages of LTI ( Linear Time Invariant ) systems over other systems? [duplicate]

In our engineering academics, there is one subject named "signals and systems". In this subject only LTI system is discussed. I want to know what are the advantages of LTI systems over other ...
1
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4answers
302 views

Sampling Theorem: How to know the value between two samples of a Signal

According to Sampling theorem, in order to reconstruct a signal we need to sample it at the rate => twice the highest frequency component of that signal. (provided signal is band limited). Let's say, ...
1
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2answers
3k views

Estimation of Instantaneous Amplitude

I'm reading a paper on EMG analysis. The formulas are all clear to me, but the paper refers to the signal amplitude as "instantaneous" amplitude. I know what instantaneous mean, but what does it mean ...
1
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2answers
208 views

What is meant by *sampling* in terms of the *sampling theorem*?

Let $y:\left(-\frac T2,\frac T2\right)\to\mathbb{C}$ be a square integrable function. The Fourier coefficients of $y$ are $$\underline{Y}(k):=\frac 1T\int_{-T/2}^{T/2}y(t)e^{-i\omega_kt}\;dt\;\;\;\...
1
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2answers
84 views

How to restore an image from its filter output?

I'm wondering if there is a way that I can reconstruct an image, given the output vector obtained from the convolution with a certain filter. For example I convolve my image with a filter from MR8 ...
1
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1answer
2k views

Showing frequency and amplitude after doing an FFT on a signal

I have executed an FFT on a .wav file of a person saying "ahhh" which shows the frequency and amplitude of the audio file. When I run it on a .wav file it shows the frequency 0 Hz as having the ...
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3answers
80 views

Significance of Sinusoidal signals

Can anyone tell what are the significance of sinusoidal signals in the field of science and engineering? sorry for being noob,
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2answers
313 views

How to edit audios so that they have the same length

I have a dataset of audio files, which differ on their lengths by a couple of milliseconds. Some are little shorter than 1s and some are little longer than 1s. They all have the same sampling rate, ...
1
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2answers
5k views

Multiplication of two impulse function $\delta(t)\cdot \delta(t)=?$

If a impulse function is mulplied with a function $f(x)$ then the formula will be apply $$f(x)\delta(x-a)=f(a)\delta(x-a)$$ so from this formula mulplication of two impulse function will be $$\...
1
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1answer
1k views

Design narrow bandpass filter for signal with high sampling rate

I have to bandpass-filter a signal which has been sampled with 4000 Hz. Only frequencies around 15 Hz shall remain after filtering (let's say in a band between 10 Hz and 20 Hz; the narrower the ...
1
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1answer
275 views

Applying a Liftering function to an audio signal

Is it necessary to perform the liftering function before applying MFCC to an audio signal?