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Questions tagged [signal-analysis]

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0
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1answer
52 views

Effective Nyquist frequency / signal resolution for overlapping time averaged signal samples

Say that I have a continuous signal. If I sample the signal at sampling rate f_sample, then the highest signal frequency that I can resolve without worrying about ...
0
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1answer
162 views

What is the difference between undersampling and oversampling in analog to digital conversion ?

When converting a signal from analog to digital, we observe undersampling and oversampling. Does oversampling means that the sampling frequency is greater that the signal's frequency and does ...
0
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0answers
27 views

Adaptive frequency discovery of binary signal

First of all, I'm not a signal processing expert. Actually, I'm trying to benefit from some concepts of signal processing theory in my computer science research. My problem is that, I have to find ...
0
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0answers
19 views

how to do supervised NMF source separation?

I know how NMF works by itself (unsupervised), but I am now interested in learning how it works in the supervised way. Suppose I have a clean isolated time domain signal of about 3 seconds in length ...
0
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1answer
82 views

Difference between acoustic emissions and ultrasonic waves

I need some clarification about the difference between acoustic emissions and ultrasonic waves. I have the idea that both are high-frequency signals and informative frequency bands more or less ...
0
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1answer
47 views

How to build a realtime simple audio spectogram? [closed]

I'm trying to build a spectogram view of history time of 4 seconds and I'm stuck at the part where you load/draw FFT vectors into the 2D bitmap. I just don't know how to do that, but i got the FFT in ...
0
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1answer
21 views

Correct form of discrete-time Fourier series representation

As I see in this slides, Fourier series representation for discrete-time signal $s[n]$ with period $N$ is $\sum_{k = 0}^{N-1} c_k e^{j2\pi k n / N}$ According to Wiki, Fourier series representation ...
1
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0answers
39 views

Advances in Blind SNR estimation beyond $M_2M_4$

In Pauluzzi and Beaulieu, various SNR estimation methods are compared. Among the blind methods considered, the $M_2M_4$ estimator seemed to be unambiguously the best. However, it has been shown that ...
0
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1answer
69 views

Is there an example of an infinite signal? [closed]

In the real world, Is there an example of an infinite signal?
17
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3answers
3k views

Show others how I hear myself

Sooo .. I've been thinking about this stuff. We all know that we sound different from what we hear of our own voice. It is easy to find out how others hear us by recording oneself and listen to it. ...
1
vote
1answer
115 views

Can a Fourier Transform exist even if the j$\omega$ axis is not in the Region of Convergence in it's Laplace Transform

A couple of confusions have been occurred. The Signal I'm considering is f(t) = sin(t)*u(t) Fourier Transform of it can be derived. $-i \pi (\delta (\omega -1)-\delta (\omega +1))$ According to my ...
1
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0answers
218 views

How to envelope a non periodic Impulse signal?

I want to analyse a trc oscilloscope file, find impulses and envelope them. In the end I want to plot the envelope. data file (trc): https://ufile.io/z4m4d Code: (Python) ...
-1
votes
1answer
18 views

When does a color channel such as RGB carry more info than a grayscale channel or image?

Typically a gray-scale image gives us more information about an image in terms of a signal processing problem. But when does a color channel carry more info than a gray-scale channel? I understand ...
0
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1answer
30 views

EEG Sampling, Which Order should cover my result?

I have EEG data sampling rate is 250 Hz and I want to band pass this data in ( 0.5-3 Hz & 3-8 Hz & 8-13 Hz & 13-30 Hz & 30-40 Hz). Currently, the data is in the frequency range of ...
0
votes
1answer
31 views

What's the point of using Morphological processing concerning images?

I dig deeper in internet to figure out what's the point of morphological processing on images, but i'd rather to hear the answer from people with experience, can you give me a hand with this? Thank ...
0
votes
1answer
81 views

Are resolution increase and noise reduction from oversampling mutually exclusive?

Oversampling a signal means sampling it with a significantly higher sampling frequency than the Nyquist rate. As far as I know, there are three advantages: Easier design of anti alias filter Increase ...
1
vote
1answer
55 views

Spectral averaging without phase information

In the context of signal averaging to reduce uncorrelated noise: Is it possible to perform signal averaging from just the magnitude spectrum of certain signals? Or that would only work if we know ...
0
votes
1answer
22 views

Characterization of the amount of modulation in a signal

We have used the ICRA babble noise to generate an 8-talker babble. As a background - babble noise is used as a substitute for competing talkers as babble noise lacks lexical content, but contains the ...
0
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1answer
75 views

Figuring magnitude and phase response

I've got a linear time-invariant system $$y[n]=\frac{8}{9}y[n-1]+x[n]$$ which I transformed into a transfer function $$Y(z)=\frac{8}{9}Y(z)*z^{-1}+X(z) =>\frac{Y(z)}{X(z)}=\frac{1}{1-\frac{8}{9}*z^{...
0
votes
1answer
142 views

How to determine fundamental frequencies (beats/minute) of heartbeat? (matlab)

read = matfile('ECG.mat'); [cor, lags] = xcorr(read.ecg, read.ecg); read.Fs; So i have read.ecg (signal) and ...
3
votes
1answer
48 views

Compare two signals, find times when they are affected by the same processes

I have two (noisy) signals $S_1(t)$ and $S_2(t)$. They contain information on three distinct events occurring in a physical system. Event $A$ affects only $S_1(t)$, event $B$ affects both $S_1(t)$ and ...
0
votes
1answer
190 views

What is the difference between Spectrogram and Scalogram?

Could someone please explain the difference between the two? Spectrogram: A visual representation of the spectrum of a sound changing through time. Scalogram: (signal processing) A visual ...
2
votes
1answer
80 views

Denoising a signal using eigendecomposition

I have a complex observable series $Y(t)$ which is the result of summing two complex r.v $X(t)$ (unobservable) and a $\epsilon(t)$ (unobservable). $$Y(t)=X(t)+\epsilon(t)$$ Assume that $X$ and $\...
0
votes
2answers
231 views

How to compute the channel gain from the path loss model of a wireless channel

I did my research but I did not get a satisfying answer. We have a transmitter and a receiver over a wireless communication channel. The channel's path loss is modeled as $ 128 + 37 \log_{10} (d)$, ...
0
votes
1answer
48 views

How to find the coefficients of the following differential equation

An arbitrary signal $v(t)$ pass through the following system, $w'(t) + 5 w(t) = v'''(t) + 320v''(t) + 40 v' (t) + 40v(t)$ How to determine the coefficients of the following differential equation, ...
2
votes
1answer
95 views

Linear Predictive Coding for general signals

I have a signal that's monotonic and roughly linear and have been looking at using Linear Predictive Coding to encode information and compress my signal. I guess my first general question is if this ...
-1
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1answer
21 views
0
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2answers
57 views

Accurate description of the spectrum of sinusoid waveform added with WGN?

The transmitting signal is $$ s(t) = \sin(20\pi t)+\sin(40\pi t)+\sin(60\pi t) $$ The received signal after AWGN channel is $$ r(t) = s(t)+n(t) $$ where the variance of noise $n(t)$ is $\sigma^2$. ...
1
vote
0answers
41 views

Frequency bins too powerful at the start and at the end of each sample computed DFT data

I've taken the following link http://coding-geek.com/how-shazam-works/#comments as a project to start practising and learning signal processing and python programming for me to get started in speech ...
4
votes
3answers
277 views

Is Linear Prediction ever exact?

I'm just learning about linear prediction and was wondering whether or not there are any signals that would produce no error if run through a linear prediction algorithm. I was thinking (maybe naively)...
2
votes
0answers
55 views

FFT Service on AWS? [closed]

Hopefully this is the right forum to post this question. Initially posted to Meta. My mistake. Learned the hard way via downvoting. I searched AWS and Microsoft cognitive services for an FFT web ...
1
vote
1answer
33 views

make a voice sound signal play faster

Suppose $x(t)$ is a signal containing a voice. How can one derive a signal playing the same voice faster. I tried $x(t+\lfloor{100t\rfloor}/100)$ to double the speed; But it adds a buzz sound. Is ...
1
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1answer
106 views

GPS Coarse Acquisition PRN Codes

Are the actual 1023 bit sequences for each of the 32 GPS satellites available to consumers? I found the IS GPS 200 but it doesn't list the entire sequences. Are verified sequences available for ...
1
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0answers
58 views

How to estimate noise by eigendecomposition of the variance covariance matrix?

I'm new here so I will try to be as clear as possible. I am trying to apply some techniques from signal processing framework to denoise financial time series. I would like to know if what I am ...
1
vote
1answer
325 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 ...
-2
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1answer
56 views

Signal reconstruction from sampled signal? [closed]

Can we construct exact analog signal at receiver as same as the source from the sampled signal?
0
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1answer
69 views

Implementing real-time signal processing filters

I’m currently working on my capstone for school, and I’m looking for some guidance/tips when it comes to real-time filtering. The nature of the project is to monitor breathing patterns, send the ...
0
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1answer
43 views

Signals and Systems - LTI - Transforms - Impulse Response

I have $x(t)-> LTI -> y(t)$ where $LTI=h(t),H(jw)$. and $H(jw)=ab/((a+jw)(b+jw))$ where a and B are real numbers. I am wanting to find the impulse response $h(t)$ as well as the input/...
0
votes
1answer
39 views

Find identical audio signal

I have a long audio file (in wav) and a short audio file (in wav) that has been copied from the long file. Now I need to find the correct location where the short signal has been copied from. I tried ...
-2
votes
1answer
33 views

Frequency component not filtered properly

Are frequency components other than wanted signal present in the output? If yes then why does it not disturb the original signal? I think all practical filter responses are not ideal, so all frequency ...
0
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1answer
60 views

Real and Imaginary data from Network Analyzer

I’m having a hard time grasping what exactly ARE the real and imaginary numbers in my s-parameter data. Most of the time I just set the NA up in logmag/phase to find the loss though, say, a filter or ...
1
vote
1answer
125 views

Finding audio “tics” in stereo wav files using python

I have thousands of audio files that I want to "batch" process searching for audio tics. This is easily done using a DAW but that requires opening each file independently, searching for the tic (...
0
votes
1answer
43 views

Equalization : using the spectral or the temporal signal?

I'm trying to equalize a sound signal - using a JAVA program - and I'm using this process : 1/ Conversion of the temporal signal to a spectral signal, using a FFT 2/ Applying a coefficient to each ...
1
vote
1answer
97 views

Damped sinusoidal form FFT of signal

I'm doing an assignment for the course Signal analysis where I have to analyse a signal. I've tried quite some things now but it's still bothering me that the FFT is looking weird, and not looks like ...
1
vote
1answer
43 views

Ways to parallelize Sifting in EMD (Empirical Mode Decomposition)

Sifting process, which is recursive in nature, is used in EMD (Empirical Mode Decomposition) to decompose the signal (x(t)) into Intrinsic Mode Functions (IMFs) and residue, which is a monotonic ...
1
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0answers
24 views

What is the signal-noise model of laser induced fluorescence?

The following image is an example of a fluorescence signal trace from the photomultiplier tube detector (PMT). Each spike represents one fluorescently labeled cell. This signal model is definitely ...
0
votes
1answer
65 views

What's the difference between SISO and SIMO in using matched Filters

Suppose we are transmitting a signal $x$ in $OFDM$ with $N$ subcarriers, After performing Parallel/Serial conversion and then N-points FFT, we suppose to have signal $s = IFFT^Hx$, Then adding the ...
1
vote
1answer
49 views

Why are binary signals drawn continuous in time despite being a digital signal

The conventional definiton of a Digital signal is as follows: A digital signal is a signal that is discrete in time and quantized in amplitude. Almost all resources (textbooks, online sources,etc) ...
0
votes
1answer
49 views

MMSE of X given PDF

"Suppose RVs $X$ and $Y$ with probability distribution functions $F_X$, $F_Y$, and $F_{XY}$. Find a linear estimate $\hat{x}$ of $X$ by the observed $Y$ such that $\hat{x}$ correspond to the minimum ...
-1
votes
1answer
82 views

Why do we need the power spectral density?

Since the power spectral density is just the squared of the fourier transform, why is it useful ? Can't I just replace every solution that requires the psd with the fourier transform ?