Questions tagged [signal-analysis]

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3answers
227 views

Could multiple echo reflections be combined to improve signal to noise ratio?

I am working on a system processing ultrasonic echo reflection. The transmitter creates a short ultrasonic pulse and the receiver analyses the reflection. If I send two pulses (back to back or with ...
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1answer
119 views

Characterising a system from its input and output

I have 2 data sets sampled at regular intervals which represent the input and the output of a system. A quick analysis of the plots shows the following: There is a proportional factor between the ...
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3answers
256 views

Study Signal Processing

I'd Like to ask two questions : What is the difference between studying Signal processing (both Deterministic and statistical) in Department of Electrical Engineering versus Department of Mathematics ...
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1answer
220 views

Q and I part in QAM

I have one confusion in QAM about in-phase I and quadrature Q part, i.e. do they transmit identical data or not? For e.g. if i have 11001001 as a byte to be transferred, so will 4-QAM separate it like?...
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2answers
2k views

Can the order of filtering and downsampling be exchanged?

Say for example, I have a signal with maximum frequency at 600Hz, and I originally oversampled it at 2000Hz. Afterwards I was only interested in frequency less than 500Hz. I guess I could first filter ...
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2answers
8k views

Negative dB signal to noise ratio

Is it common to find systems having signal to noise ratio (SNR) less than 1 i.e. noise is more than signal? I am currently working with SNR of -5db to -20db. And how useful is it to work with sensor ...
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2answers
81 views

how can i get to know the frequency of a speech signal?

What is the actual meaning of frequency? what if the signal is aperiodic?? In general, we say that frequency means the repeatition of an event in unit time. But what about a speech signal? how can we ...
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0answers
805 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 ...
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1answer
299 views

converting block diagrams with delays to equations

given this block diagram: can someone please clarify how to interpret the second delay (the one prior to $Y$)? to convert this block diagram into a simple equation, I interpret the diagram as: ...
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0answers
1k views

In a signal there is a peak, I want to find the start of the peak and the end of the peak

I want to the start time and end time for the peak shown below. The start and end are shown by the marked circles in the fig As there are number of such plots and want to know start and end time for ...
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1answer
281 views

Describing Function for non-symmetric Saturation Model

Let's talk about a standard saturation model: with bounds $bound_{lower}$ and $bound_{upper}$. So in this example the output $y$ will be: \begin{equation} y(u) = \begin{cases} bound_{lower} ...
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1answer
49 views

How to decode speaker gender from spoken transcript

I have 20 audio recordings (raw format) of people reciting the same ~50 word transcript. I would like to use audio signal analysis to decode speaker gender from audio recording. Intuitively, it ...
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0answers
72 views

Interpolation methods for radar and acoustic imaging and potential pitfalls

A) What are the most common methods used to remap data for current generation imaging radars and acoustic sensors? B) What are some of the pitfalls in these methods? For example, in the past, at ...
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1answer
125 views

When was the time-frequency analysis invented?

It seems there are several papers from the seventies but backtracking from the references gets quickly difficult. Who calculated for the first time a time-frequency representation of a signal?
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1answer
58 views

Time shift — two interpretations

In their textbook(Example 1.1), Oppenheim and Willsky provide the following method for obtaining $g(t)=x(-t+1)$ from $x(t)$ : Replace $t$ with $-t$ in $x(t+1)$. In other words, advance the signal by 1 ...
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1answer
25k views

How to calculate Signal-To-Noise Ratio

I am doing some analysis in python working with a photodiode. The signal is more or less periodic with some phase shifting in certain areas that give rise to faster or slower periods but overall still ...
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0answers
107 views

How to replace Hadamard Product and Column wise addition with new Matrix operation?

Let $$ A= \begin{bmatrix} a_{1,1} & a_{1,2} & a_{1,3}\\ a_{2,1} & a_{2,2} & a_{2,3}\\ a_{3,1} & a_{3,2} & a_{3,3}\\ \end{bmatrix} $$ and $$ B= \begin{...
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1answer
83 views

Time Invariance

I cant understand this when I have a system thar compress the input as follows $$y(t)=x(2t)$$ Now to check for time invariance now I should input $x(t)$ to get $$y_1(t) = x(2t)$$ Then I should input $...
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1answer
388 views

minimum frequency in periodic components

Suppose we have the following signal model $y(t) = A_1\sin(\omega_1 t+\phi_1) + A_2\sin(\omega_2 t+\phi_2) + ... + A_p\sin(\omega_p t+\phi_p) + z(t)$ When we are sampling at sampling frequency $f_\...
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2answers
3k views

Preprocessing audio signal for neural network classification

I need to identify certain features of the audio signal recorded from microphone in stethoscope. These sounds are only samples i've found, but the final signal will be probably a bit noisier (maybe ...
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1answer
159 views

Amplitude Spectrum, Nyquist Frequency, mixed/min/max wavelets

The problem is here. Now I know the definition of mixed/max/min phase wavelets, whether the roots lie within the unit circle or not. Starting from n = 1, let $$ x_t = ( 5, 6) $$ $$ X(z) = 5 + 6z $$ ...
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1answer
275 views

What is the general feature of a time domain signal that gives a step like spectrum?

I'm trying to study a nonlinear system by sending a pulsed signal into the system and look at the response spectrum. The signal I send to the system is something like and the response spectrum from I ...
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1answer
221 views

Epoched data to a continuous signal

if we create a continuous signal from epoched data (say, EEG data with 100 epoches), what kind of problems it may cause( i am only aware of edge artifacts ) and how i can avoid them in analysis (say, ...
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2answers
131 views

number of possible component in sinusoidal model

Suppose that we have the following model $y(t) = A_1\sin(\omega_1 t+\phi_1) + A_2\sin(\omega_2 t+\phi_2) + ... + A_p\sin(\omega_p t+\phi_p) + z(t)$ My question is not related to how to determine the ...
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1answer
211 views

filtering fft spectrum further?

I am working on bearing faults.I did the high pass filter and then calculated the envelope of the signal in the time domain. I then found its fourier. The fft spectrum is still not clear. My ...
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1answer
64 views

Estimate digital signal

I have a device that connect with USB to my computer. This device have digital signal that I can sample it every few seconds. The signal that the device perform, is a digital signal with $X$ seconds ...
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0answers
126 views

Time delay analysis in different binary sequences

I am extracting a property of a signal which I represent with either a 0 for absent or 1 for present. This property is extracted for each data point in a time series and in the end I am left with a ...
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2answers
9k views

What is 'energy compaction' in simple terms?

This is my understanding of 'energy compaction' and want to know if it is right. Take a vector. The energy of the vector is the sum of the squares of its elements. If A is the transformation matrix ...
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1answer
88 views

Reduce the “glare” effect of a receiver within a system

I'm working this summer on a very interesting, albeit difficult to understand at 100 %, project and it turns around reducing the glare effect than could be applied on a receiver when he gets signals ...
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1answer
393 views

Does modified Morlet wavelet function satisfy the admissibility condition?

Does modified Morlet wavelet function satisfy the admissibility condition ? Do you have any reference for the answer please. Thanks.
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1answer
1k views

how to get the phasor(frequency domain) representation of a digitalized signal?

I know that we can get the phasor representation(frequency domain) of a signal through Fourier transform, but the picture above gives a method that can get the phasor representation of a signal in a ...
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0answers
104 views

How to synchronise two audio files using a marker

I'm working on a project on which we use WebRTC and the RecordRTC library to record audio files. I would like to be able to process the audio files server-side to ensure a good synchronisation. To ...
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1answer
65 views

Counter design for audio signals

I am designing a schematic in which a Counter is to be increased whenever a particular band of frequencies is received at the Audio input. We are receiving the audio input as electrical Signal and I ...
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1answer
252 views

How to get the signal to noise ratio from noisy data set with sinusoid?

I'm new to DSP and trying to do some example problems for a class and am confused by this one. Given a data set, and knowing it contains a signal that is a single sinusoid with random content noise, ...
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1answer
112 views

Parameters for signal analysis

I am extremely new to signal analysis. And before posting I did a lot of reading on signal analysis, FFT and windowing. I am working on my thesis which involves comparison of speech signals lets say ...
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1answer
185 views

Noise rejection / feature extraction

I'm hoping someone could point me in the direction of some signal processing methods to clean up my data. I'm collecting physiological data from human muscle (lower leg; gastrocnemius) during walking/...
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0answers
48 views

I'm interested in the state-of-the-art of vocal sound synthesis. Please advise me [closed]

Some of the things I'd like to accomplish: Strip the vocals from a recorded song as best as possible Recreate someone's song voice (like a famous artists') using someone else's voice as input Adjust ...
3
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1answer
77 views

Variance of an Implicit Function of Kalman State Vector

Given a state vector given by $ x = {[r, v, a]}^{T} $ (Range, Velocity, Acceleration) the Time to Hit is the the time which holds the following: $$ r + v {T}_{tth} + \frac{a {T}_{tth}^{2}}{2} = 0 $$ ...
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1answer
81 views

What does it mean for audio to be 'sped up'? How can I undo it?

I very simply have a .wav audio file, but there is a note with it that says "This audio has been sped up by 10x". I am wondering, what does it mean exactly from a signal processing perspective for an ...
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2answers
82 views

Need to calculate $\frac{E\left[|x(n)|^4\right]}{E\left[x^2(n)\right]}$

I need to calculate $\frac{E\left[|x(n)|^4\right]}{E\left[x^2(n)\right]}$ in real time, where $x(n)$ is complex. For $E\left[|x(n)|^4\right]$ I plan to take the absolute, raise it to the power $4$ ...
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1answer
475 views
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1answer
1k views

relationship between block size and detected frequencies in goertzel algorithm

I'm trying to use the goertzel algorithm to detect a pair of frequencies in a signal. The sample rate I'm using is 8000 hz, and the size of the incoming sample buffer is 60 samples. I have a large ...
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3answers
3k views

How to get fundamental frequency of a signal using autocorrelation?

I am trying to get the fundamental frequency of a signal that only has a single pitch. I coded out the autocorrelation function using FFT and already got the autocorrelation result. Unfortunately, I ...
4
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2answers
569 views

Comb-like peaks in frequency spectrum

I am currently working on a project which involves measuring the sound produced by the onset of a vapour bubble in boiling water. All the experiments went perfectly well and I'm now trying to obtain a ...
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1answer
304 views

How to Concatenate white noise signal and applying bandpass filter matlab

I created a white noise signal. I am trying to use the array I have created with the white noise to play in 2 channels. When the left channel I was trying to have 5000 samples and the right will have ...
2
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1answer
759 views

Is step detection the correct approach to this problem? what if not?

I'm looking for some advice on where and what to start reading for learning to solve this. I've the time series of the position coordinates (x,y) of an animal in an open field (just a cage). I want ...
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1answer
61 views

Suitable metrics for summarizing or visualizing the spatial activation of components after temporal Independent Component Analysis (ICA)

I will first describe the Independent Component Analysis (ICA) steps, so that the question becomes clearer, and more relevant to similar questions. Assume we have $N$ sensors distributed in space. ...
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1answer
816 views

How moving part pixel intensity values of video frames becomes dominant compared to stationary part intensities in reconstructed frames?

Hello everyone i want to do dynamic texture video sementation using the Fourier transform in MATLAB. I am applying 3-D fft on dynamic texture video frames (using matlab function 'fftn') and ...
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1answer
96 views

How to store the signal in a variable and plot the signal in MATLAB

I am trying to store the signal I have created in a single variable and graph the signal in two subplots in one single graph, one for left channel, one for right channel. ...
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1answer
996 views

How to add repeated beeps to sound created with a pause in between each beep in MATLAB

I have 2 sounds that I created and trying to make them beeps. Maybe 4 or 5 repeated beeps but have a pause in between each beep but make it still part of the signal. I think I have it so that the ...

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