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.
8
votes
1answer
1k views
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 ...
0
votes
1answer
36 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 ...
0
votes
0answers
16 views
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 ...
1
vote
1answer
32 views
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 ...
0
votes
1answer
31 views
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 ...
0
votes
2answers
52 views
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?
1
vote
0answers
14 views
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 ...
0
votes
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 ...
0
votes
1answer
24 views
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 ...
1
vote
2answers
31 views
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 ...
0
votes
0answers
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 ...
0
votes
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.
1
vote
2answers
59 views
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:
...
0
votes
0answers
23 views
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 ...
0
votes
0answers
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)...
0
votes
0answers
13 views
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.
0
votes
0answers
13 views
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/...
2
votes
0answers
24 views
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)...
1
vote
0answers
15 views
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 ...
2
votes
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 ...
0
votes
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 ...
1
vote
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(...
0
votes
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 ...
1
vote
1answer
37 views
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,
$$y(t)=T\{x(t)\}=\int_{-\infty}^{\infty}x(\tau)T\{\delta(\tau-t)\}d\tau=\...
0
votes
1answer
48 views
Are there any signals with brickwall autocorrelation?
Are there any signals whose autocorrelation $R(\tau)$ has the following form? Assuming $\tau_c > 0$ and $R_0 > 0$ a constant,
$$R(\tau) = \begin{cases}R_0, \text{ for $|\tau| < \tau_c$} \\ 0,...
0
votes
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 (...
0
votes
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 ...
1
vote
2answers
154 views
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 ...
-1
votes
3answers
50 views
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 ...
2
votes
2answers
89 views
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. ...
0
votes
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 ...
0
votes
1answer
60 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
votes
2answers
35 views
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 ...
0
votes
1answer
69 views
Is there an example of an infinite signal? [closed]
In the real world, Is there an example of an infinite signal?
1
vote
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....
0
votes
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 $(A^c = [a^c_m, ..., a^c_1, a^c_0])$. ...
1
vote
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 ...
0
votes
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 ...
0
votes
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!
-1
votes
1answer
52 views
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
votes
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(\...
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, ...
0
votes
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:
$$a_k = a_1=a_{-1}=\frac{1}{2} $$
$$b_k = b_1=b^*_{-1}=\frac{1}{2j}...
6
votes
7answers
471 views
Intuition behind commutativity of convolution in LTI systems
Why is convolution commutative, as it seems to treat two signals in a different way in an LTI system?
If you imagine $y[n] = x[n] \star h[n]$ with $x[n]$ being an input signal and $h[n]$ being the ...
0
votes
2answers
54 views
How will I draw the following signal?
I want to know that if I have any signal given how will I draw it according to the following equation
$$x(t-1)-1/2$$
what will be the role of $1/2$ when drawing the new signal?
2
votes
1answer
87 views
Does the Fourier series coefficient of AC components remains same if DC component is subtracted form the given signal?
Suppose a signal is defined by
$
x(t)= \begin{cases}
t & 0\leq t \leq 1 \\
2-t & 1\leq t\leq 2 \\
\end{cases}
$
Since $x(t)$ has even symmetry, I can calculate fourier coefficient as
$$
a_n = ...
0
votes
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 ...
-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
votes
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:
\...
0
votes
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 ...
