Questions tagged [continuous-signals]
A continuous signal or a continuous-time signal is a varying quantity (a signal) whose domain, which is often time, is a continuum.
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How to design a digital Butterworth bandpass filter?
I am looking into designing a Bandpass Butterworth filter in python, but, I was not sure I am designing my filter correctly. What I have are the following:
High cutoff frequency = 200Hz
Low cutoff ...
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0answers
21 views
How to design function for Random Decrement technique in python and implement the function?
I was looking into a technique called Random decrement technique from the following links/articles:
How can I use Random Decrement Method to convert a non-stationary
signal into a decay function ...
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3answers
50 views
Doppler shift in signals
I have started doing some reading into the effects of the doppler shift on signals. In particular, radar signals from ships moving relative to a receiver. This might seem weird but I understand why ...
0
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1answer
66 views
Fourier transform of $\textrm{sinc}^2(100\pi t)$
I'm confused about a tutorial problem concerning the Fourier transform of the $\textrm{sinc}^2$ function.
Specifically, the question involves the Fourier transform of $\textrm{sinc}^2(100\pi t)$, ...
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2answers
68 views
How are pole-zero plots, magnitude response plots, and phase response plots related?
Given that the Laplace transform of a continuous-time signal $h(t)$ is $H(s)$, what can a plot of the poles and zeros of $H(s)$ on the $s$-plane tell me about the magnitude response and phase response ...
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1answer
31 views
Time Invariance of Continuous Time System
I am trying to check whether the system given by the following input-output relation is LSI or not?
$$y(t) = \cos(x(t)-x(0))$$
My work:
The given relation: $$y(t) = \cos(x(t)-x(0))$$
If the input ...
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0answers
6 views
How to create an objective function for Mackey glass time series (using "bayesopt")?
I am optimizing 5 hyperparameters of Mackey-Glass time series and using built-in function "bayesopt" in MATLAB. My Mackey glass time series with fixed parameters shows correct results. ...
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0answers
21 views
How can we translate this statement into an input signal expression?
I want to make sure if I got this right, the following statement:
if the operator
enters a unity sloped linearly increasing input then the output must eventually track the
input and be at most 0.1 cm ...
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0answers
15 views
Where is SNR and CNR calculated for LTE?
I read below that SNR and CNR are different and we have difference of post/pre modulation.
In context of LTE which modulation do we refer to- Digital Data modulated using QAM/QPSK to IQ, or Baseband ...
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1answer
33 views
CTFT of $ X(j\omega) $ vs $ X(jf) $
The CTFT of a signal as a function of $ \omega $ and $ f $ is identical:
$$ X(j\omega) = \int_{-\infty}^{\infty} x(t) \, e^{-j \omega t} \operatorname{dt} \;\;\;\;\bigg|\;\;\;\; X(j f) = \int_{-\infty}...
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1answer
77 views
How do we equate the signal energy before and after sampling?
I have a band-limited signal and sample it at sample rate of $f_\mathrm{s}$. By taking the continuous time fourier transform, I will see copies of the same signal at $n\cdot f_\mathrm{s}$ where $n \in ...
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16 views
Blind source separation for asynchronously observed mixture channels
Given your practical and theoretical expertise: Does ICA work reliably when applied to a multidimensional mixture (observation) $X = (X^1, \cdots, X^d)$ if the different channels $X^i$ of the ...
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1answer
36 views
Convolution of a discrete continuous function for reconstruction
From chapter 9 page 198 of https://github.com/t4world/Computer-Graphics/blob/master/Fundamentals-of-Computer-Graphics-Fourth-Edition.pdf
I am confused as to what this book's description is saying ...
3
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1answer
117 views
What would be an example for a continuous signal from "daily life"?
Please share an answer with a simple example from the "daily" (colloquial) lives of humans for a signal which is "continuous" and explain what is it that rigorously makes it "...
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1answer
59 views
Check whether a system has memory or not
My question is whether the systems below are memoryless or not:
$1.) \ y(t)=K$ where $K$ is a constant
$2.) \ y(t) = x(t_0) $ where $t_0$ is a constant
So, from the definition I have been using so far ...
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2answers
35 views
Power spectral density after a modulator block
For random signals, the concept of Power Spectral Density is useful to analyze the signal. It can be shown that if the input $X(t)$ applied to an LTI system of impulse response $h(t)$ has the PSD $S_{...
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1answer
111 views
Fourier transform of an impulse-train sampled signal
I'm trying to calculate the Fourier transform of an impulse-train sampled signal in two differnt ways but I end up with different results.
Impulse-train sampling of a continous signal $x(t)$ with ...
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0answers
43 views
How to remove noise from the signal? [closed]
I'm new to DSP and currently working on time-series data. The mentioned time series (of Toe) is extracted from a video tracking various body parts of an athlete. Ideally, there shouldn't be any ...
2
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1answer
51 views
Fourier transform of shifted periodic function
Assuming $x(t)$ is a periodic function of period $T$ and having the Fourier transform $X(\omega)$, it is required to calculate the Fourier transform of the signal $x(t)+x(t-T)$. Since x(t-T) is equal ...
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6answers
834 views
Do discrete-time series always have a continuous-time underlying?
Can one argue that discrete time-series coming from stocks or commodities (prices) are derived from a continuous-time process?
One can probably argue that stocks or commodities at any time have a ...
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35 views
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1answer
37 views
Integration of Sinusoidal functions
Since Differentiation of a sinusoidal function of a certain angular frequency gives a sinusoidal function of the same frequency, does the statement "Integration of a sinusoidal function of ...
3
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1answer
86 views
Comparing distribution of vectors with different length?
I have two vectors of different length, each vector contains similarity scores. I need to plot the probabilty density function of the scores in both vectors to compare their distribution using Matlab. ...
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1answer
58 views
Conditions for stability in $s$ domain?
What are the necessary conditions for stability in $s$ domain, especially in regards to ROC.
I am able to understand that there are only two conditions
First condition: all poles must be on left half ...
2
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6answers
270 views
What happens when we oversample?
I had an interview for a wireless communication position and one of the interviewers asked me this question in regard to signal processing.
If I have signal and I sample at the Nyquist frequency and ...
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1answer
43 views
Is "Introduction to Statistical Signal Processing" by RM Gray good for starting?
I am working on noise processes in electronic devices for my studies, by now Ive been doing a fairly large amount of processing of time measurements, like calculate PSD, estimate thermal, flicker ...
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0answers
45 views
The definition of amplitude probability density
I'm trying to figure out the formal definition of "amplitude probability density"(APD). First of all I didn't find a textbook which defines APD but there are some sources that explain it ...
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1answer
66 views
When to zero-mean a signal?
I have two sets of signals. The first is a noisy sinewave, which I zero-mean before taking the FFT since I need to find the amplitude.
The other is essentially noise with a gaussian distribution. I'm ...
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5answers
173 views
Why does twice the sampling rate (Nyquist Theorem) seem inadequate?
I was told in my electronics course that "to reproduce a wave, we need to sample it at least twice every period."
If I take this to be literally true, then a sine wave with only 2-3 samples ...
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2answers
66 views
Are signals modeled either digitally or analogously or can signals modeled as both?
Are signals modeled either digitally or analogously or can signals modeled as both?
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1answer
83 views
Correlation and the Fourier transform
In the book Fundamentals of Music Processing: Audio, Analysis, Algorithms, Applications by Meinard Müller, the coefficients $d_\omega$ and $\phi_\omega$ are defined as
where $\cos_{\omega,\phi}(t) = \...
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2answers
111 views
When joining two signals of different frequencies how do I find the phase shift that makes the join smooth?
I'm generating a sine wave and I want the second half of the signal to be in a different frequency.
How do I find the phase shift I can apply to the second half so that the joining between the halves ...
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1answer
43 views
Different mathematical signal models for different applications
I am looking for some interesting and physically meaningful applications of different signal models. I am currently working with complex analytic signal model given below, but I couldn't come up with ...
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0answers
31 views
Estimate respiration rate from a respiration signal
I have a respiration signal sampled at frequency 125Hz, can I estimate respiration rate signal at a frequency 1HZ from the respiration signal? Is it possible to use FFT or FFT for this purpose in ...
0
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1answer
38 views
Is a continuous time aperiodic signal discrete in the time domain?
This is a statement I have read from a textbook:
Whenever we have periodic signals continuous or discrete time the frequency domain is discrete and time domain is continuous.
Whenever we have ...
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3answers
117 views
How is a constellation diagram constructed in practice?
I am simulating some optical signals in Matlab as they pass through a waveguide, get amplified, mixed with noises, etc. For the record, I am a theoretical physicist, not an engineer nor an ...
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0answers
46 views
convolving an LTI with filters
I just started learning signal processing and one of the very first topics I begun with is convolution. I want to learn signal processing practically, therefore I opted to work with circuits(also a ...
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1answer
34 views
Mixed - Discrete and Continuous system Laplace domain stability - Effect of Sampler and DAC
I have a system whose the plant transfer function is continuous and the compensation is discrete. I have an ADC which allows to measure the output of the system and a DAC which allows to control the ...
2
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2answers
63 views
Meaning of Rect and Train of Rect Spectra
The Fourier transform of $x(t)=\operatorname{rect}(t)$ is $X(f)=\operatorname{sinc}(f)$
The Fourier transform of a periodic train of rectangular pulses $x(t)=\sum\limits_{n=-\infty}^{\infty}\...
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2answers
270 views
A system having impulse response $ h(t)=u(t) $ stable or not?
I know that for a system to be BIBO stable its impulse response must be absolutely integrable and the impulse response $ h(t)= u(t)$ integrates to approach infinity (i guess)
I proceeded as$$ \int_{-\...
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1answer
152 views
Fourier Transform of $u(t)$ [duplicate]
I am just unable to find the correct Fourier transform of these signals (unit step, sine and cosine functions) which are containing delta functions in their Fourier transform.
For unit step function,
...
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2answers
40 views
Is it possible that the value of a continuous mother wavelet at origin is zero, i.e. $\psi(t=0)=0$?
According to Fourier transform, a continuous wavelet could be written as
$$
\psi(t)=\frac{1}{2\pi}\int\hat\psi(k)\text{e}^{-ikt}\text{d}k
$$
From the equation above, we know that $\psi(t=0)$ is
$$
\...
2
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4answers
102 views
Meaning of frequency and bandwidth of a signal, despite the fact that we do not know the signal
First of all, I am completely new to the domain of signal processing.
As far as I know, a signal can be represented with an infinite integral of infinitesimal complex exponentials, which is known as a ...
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2answers
45 views
What's the point of defining the signal over the whole time domain?
This question is classic for anyone starting with some signal processing course, suppose $y(t)=x(t/2)$ then the system is noncausal because we have that the output at t=-6 depends on the input at t=-3 ...
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0answers
10 views
Finding the wiggles pattern in the original dataset. (Wiggles appear after performing division by another dataset)
I have multiple measurements regarding scientific observations. The problem is that there is a subtle noise pattern caused by the instrument - the wiggles. These wiggles are invisible when looking at ...
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0answers
38 views
Finding the integral of a signal
I'm trying to find the integral of the following signal:
$x(t)=A, 0 \le t \le T$
$x(t)=0, otherwise$
The integral is defined as
$y(t)=\int_0^t{x(\tau)d\tau}$
For $y(t)$, I'm getting $AT$ when $t \gt T$...
2
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1answer
78 views
Linear system stability criteria
Suppose we have a closed-loop system $H(s)=\frac{A(s)}{1+A(s)f(s)}=\frac{A(s)}{1+T(s)}$. I've seen the stability of the system stated a couple ways:
If $H(s)$ has any poles in the RHP, then it is ...
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2answers
78 views
Periodicity of complex exponential in continuous and discrete time (Eq 1.51, Signals and Systems by Oppenheim & Wilsky)
Hi All: This is very basic but I've always wondered about it and now I see it in print in a textbook so I may as well ask. In Signals and Systems on page 26, it says
$$e^{j(\omega_0 + 2\pi)n} = e^{j2\...
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2answers
81 views
Best temperature compensation equation?
I'm looking for the correct temperature compensation equation to use on our project.
We are measuring the output of a detector who's signal is very sensitive to temperature drift.
Any external ...
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2answers
270 views
FFT of square wave - what does output represent?
I am really new to FFT and signal processing. I am doing an analysis of square waves with FFT and I am trying to understand why the FFT output on the frequency domain has a downward slope for square ...
