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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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Why doesn't sampling a periodic continuous-time signal yield a periodic discrete-time signal?

I have been studying signals and systems lately and I have came across the following claim: The uniform sampling of a periodic continuous-time signal may not be periodic! Can someone please ...
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37 views

Conversion from continuous to sampled signal?

I am bit confused regarding sampling as i read different types of statements in different texts Forexample i have a continous time signal $x=sin(t)$ defined for $t=0:10$ and i want to sample it with ...
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why we use time step only in continuous convolution in MATLAB? But not in discrete convolution?

I am studying convolution from book of alex palamides but i am confused because he uses time step(in this case 0.01) in his code for continuous convolution as shown highlighted in attached photo but ...
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Usefulness of Matched $z$ transform Method

I'm aware that the matched $z$ transform method maps between the continuous $s$ plane and the discrete/digital $z$ plane but my question is - when would this be necessary? Why would we need to convert ...
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explanation of Hybrid systems?

I want to study Detailed explanation of hybrid systems?Which incorporate both continuous and discrete time signals & systems? for example In which a continuous-time input signal is transformed ...
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negative value of signals

can we say there is no sound produced when the amplitude is 0? if yes what can we say when the amplitude is negative?
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Continuous-time RNN and Shannon sampling theorem

The most-used discrete-time RNN equations used in Deep Learning these days are those of Elman: I have seen two very different continuous-time version of these, with different justifications. The most ...
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1answer
26 views

Are the error probability of orthogonal signal and on/off signal the same?

I have to write the error probability of orthogonal signal and on/off signal,and now i have finished the error probability of on/off signal,but i don't know how to write the code about error ...
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Time Setting of $z$ and Laplace Transforms

I'm aware that the z-transform and the Laplace Transform have an analogous relationship but I want to be doubly-sure that the z-transform only works in discrete-time and that the Laplace transform ...
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2answers
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Confused in difference between sequence versus signal?

I am learning basics of signals and systems with MATLAB If i create a vector in matlab such that x=[ 2 5 10 20], will it be considered a sequence or a signal? As ...
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33 views

Detect the Beginning and Ending of a Signal

I have a signal that looks more or less like square wave signal with different phases (Like in the picture below). However, the signal fluctuates a lot, we can see in the image below: At first, I ...
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1answer
36 views

Consider the integrator and check for time invariance

I'm trying to check the following system for for time-invariance. $$ y(t) = \int_0^t x(\lambda) d\lambda$$ Please explain me why it is time-invariant.
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Confusion in linearity?

I am studying linear systems from the book "Signals and Systems Laboratory with MATLAB". I have performed an example on MATLAB myself in this regard. Code is as follow: ...
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Using MATLAB to plot the input and the magnitude spectrum of the signal

I have an aperiodic signal $v_{out} = e^{-t} u(t)$ (real exponential signal) from discharging capacitor. I was trying to plot using MATLAB 15 seconds of this signal in time domain? I am thinking how ...
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31 views

how can I know this system is Time invarient?

y(t) = 0 (t<0); x(t) + x(t-2) (t>=0); y(t) = 0 (x(t) < 0); x(t) - x(t-2) (x(t) >= 0); y[n] = x[n] (n>=1)...
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Can anyone please describe the relation between linear convolution and circular convolution? [duplicate]

It would be great if anyone could help. I am not able to find any relation amongst them, to me they are different things altogether.
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Is there any python code for applying a-law/mu-law on 3D numpy array?

I have 3D numpy array of probabilities between [0,1], I need to emphasize on some area with lower probabilities. I was suggested to apply a-law and mu-law. I am wondering if there is python library/...
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0answers
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How to remove varying noise from strain data in MATLAB

I'm very new to signal processing. I have some data measured over time at 800 Hz. I'm interested in the high frequency signals. You can easily identify them in the image below (in this case, 3 signals)...
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Extracting signal from data using Otsu thresholding in MATLAB?

I am very new to signal processing. I am trying to extract a signal from my data using otsu threholding but it's not fully accurate. In this case I know that there is going to be a single signal in ...
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2answers
48 views

How to identify the beginning and the end of a signal using MATLAB

I have multiple signals as shown in this image. I'd like automatically detect time for the earliest detection of the signal (approx 0.7e4 in S1-B3-B (orange)) and last detected occurrence of the ...
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1answer
38 views

Area under waveform in t-domain including 2 delta functions

question: my attempt: $(a)$ $\displaystyle\int_{-\infty}^{\infty} f(t) dt=2 u (t)+r(t)-r(t-T)+Ku(t-T)$ then we draw it's diagram and found it was unbounded so,we doubt how area can be zero for any ...
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1answer
29 views

How would I find the function given the magnitude plot and the phase response?

I'm wondering how I'd find the Fourier Transform X(jw) given the following information: My understanding is that the expression for the continuous time fourier transform (CTFT) is magnitude(CTFT)exp(...
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1answer
29 views

Processing using Matlab

I'm new to Matlab.As a beginner, I want to work on few signals which are used in day today life and extract useful information through it. Can someone please help me from where I could start or share ...
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1answer
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Confusion in the derivation of convolution formula [closed]

$$x(t)=\int_{-\infty}^{\infty}x(\tau)\delta(\tau-t)d\tau=\int_{-\infty}^{\infty}x(\tau)\delta(t-\tau)d\tau$$ Due to linearity, $$y(t)=T\{x(t)\}=\int_{-\infty}^{\infty}x(\tau)T\{\delta(\tau-t)\}d\tau=\...
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1answer
48 views

Are there any signals with brickwall autocorrelation?

Are there any signals whose autocorrelation $R(\tau)$ has the following form? Assuming $\tau_c > 0$ and $R_0 > 0$ a constant, $$R(\tau) = \begin{cases}R_0, \text{ for $|\tau| < \tau_c$} \\ 0,...
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1answer
35 views

Reason of effect of continuity and discreteness on periodicity of signal?

We know that a sine signal in continuous time is a periodic signal with a period $2\pi$ whereas the same sine signal in discrete time is aperiodic. My question is how changing just a type of signal (...
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1answer
27 views

response of LTI system to a Random Input Signal

what is LTI filter? what is the output when x(t) is input? let x(t) be the input signal to the system and y(t) denote the output signal. The output of the system may be expressed in terms of ...
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2answers
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A question on Fourier Series and the frequency of the sinusoids

On studying about Fourier series, I encountered 2 doubts: How is it that a non-periodic function has a Fourier series? When expressing a periodic function as summation of sinusoids, why is the ...
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3answers
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How does real-time signal processing work when the signal we deal with is assumed to be known for all times?

One thing that never sat right with me after my signal processing course is that in order to do signal processing, we must know the entire signal $x(t)$. For instance, I cannot take the Fourier or Z ...
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2answers
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DC value of $x(t)=\frac{1}{t}$

Is it possible to calculate the DC value of signals with undefinable area? More specificaly, in the case of $x(t)=\frac{1}{t}$. $\int\limits_{-\infty}^\infty\frac1t \, \mathrm dt$ does not converge. ...
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0answers
17 views

How does discrete spectral moment relate to continuous spectral moment?

It is said in discrete/digital signal processing that $r$th spectral moment of signal $x[n]$ is defined as: $$\sum_{n=-\infty}^{\infty}n^r x[n]$$ But how does this relate to usual continuous $r$th ...
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1answer
62 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 ...
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2answers
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Is there such a thing as a continuous phase BPSK?

My knowledge of signals and signal processing is limited, so I apologize in advance for my naïve and possibly confusing question. In the case of BFSK, the frequencies are altered to represent the ...
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1answer
70 views

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

In the real world, Is there an example of an infinite signal?
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1answer
45 views

Fourier Series Representation of Continuous-Time Periodic Signals [closed]

As a novice in signal processing, I have been going through Signals & Systems by Oppenheim to try and understand how continuous time periodic signals are represented by Fourier series coefficients....
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1answer
113 views

How can I get the continuous-time transfer function coefficients (or poles and zeros) from the corresponding discrete-time TF and vice versa?

Let's say I have a continuous time transfer function which I know its numerator coefficients $(B^c = [b^c_m, ..., b^c_1, b^c_0])$ and denominator coefficients $(A^c = [a^c_m, ..., a^c_1, a^c_0])$. ...
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1answer
126 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 ...
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2answers
41 views

Simple problem regarding rectangular pulse shifting

So i have the following rectangular pulse: $$h(t)=\begin{cases} 1 & 0<t< T \\ 0 & \text{otherwise} \end{cases}$$ Now, i am supposed to create $h(T-t)$, and the ...
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1answer
43 views

Bandwidth of the Derivative of a Message [duplicate]

If I have a message signal $m(t)$ and it has a bandwidth $B$. I know that the bandwidth of $m^N(t)$ is $NB$. But what is the bandwidth of $\frac{d m(t)}{dt}$? Thanks!
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1answer
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Quite confused with Fourier Analysis results

So I'm meant to show how the DFT can find the frequencies, and respective amplitudes, associated to some data. And I have this data set from the curve $$ f(t) = 1 + 2\cos(2\pi t) + 4\cos(4\pi t) $$ ...
3
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1answer
54 views

Given a plot of both the magnitude $|H(\omega)|$ and its angle, How can you find the $H(\omega)$?

I'm specifically trying to use an inverse Fourier Transform to find $h(t)$, but I'm finding it difficult to get $H(\omega)$ in the first place. I'm under the impression from my textbook that $H(\...
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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, ...
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1answer
49 views

How to do convolution in Fourier Series?

Two signals are given to me : $$x(t)=\cos(4\pi t)$$ $$y(t)=\sin(4\pi t)$$ I have founded their coefficients as follows: $$a_k = a_1=a_{-1}=\frac{1}{2} $$ $$b_k = b_1=b^*_{-1}=\frac{1}{2j}...
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7answers
471 views

Intuition behind commutativity of convolution in LTI systems

Why is convolution commutative, as it seems to treat two signals in a different way in an LTI system? If you imagine $y[n] = x[n] \star h[n]$ with $x[n]$ being an input signal and $h[n]$ being the ...
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2answers
54 views

How will I draw the following signal?

I want to know that if I have any signal given how will I draw it according to the following equation $$x(t-1)-1/2$$ what will be the role of $1/2$ when drawing the new signal?
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1answer
87 views

Does the Fourier series coefficient of AC components remains same if DC component is subtracted form the given signal?

Suppose a signal is defined by $ x(t)= \begin{cases} t & 0\leq t \leq 1 \\ 2-t & 1\leq t\leq 2 \\ \end{cases} $ Since $x(t)$ has even symmetry, I can calculate fourier coefficient as $$ a_n = ...
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1answer
59 views

Energy of compressed signals

I have tried a code to compress a signal using Compressed Sensing(CS). The input signal is $x$ and the compressed signal $y$ is given by : $y=Φ*x$ where $Φ$ is the sensing matrix. I have used ...
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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 ...
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1answer
91 views

Linearity of the given system

I am given the following system and I am checking the additive property: $$y(t)=x(e^t)$$ where $y(t)$ is the output and $x(t)$ is the input given to the system. Now this is what I did so far: \...
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1answer
29 views

Finding Harmonics Analytically

I've always obtained harmonics using simulation and never by hand. My question is how can someone find the harmonics for a signal (say a square wave) by hand? What equations come in handy for finding ...