Questions tagged [inverse]
The inverse tag has no usage guidance.
19
questions
0
votes
1answer
23 views
inverse discrete FFT in python, multiple times?
I was wondering what really happens when taking the inverse discrete FFT on some set of numbers, for 3 times? Because looking at it, it looks like we're getting an output that is identically with the ...
0
votes
0answers
23 views
Solving the system response using inverse Laplace transform
I am trying to solve this question but I got stuck when inverting the Laplace transform for this problem. I do not know that whether I do it right or wrong. Moreover, I do not know how to handle the ...
0
votes
1answer
42 views
Frequency domain Inversion of a signal
I have been trying to calculate the inverse of a sweep (by inverse I mean something that when convolved with my original signal will yield a unit impulse) and although I managed to find a time-domain ...
0
votes
1answer
33 views
Inverse Fourier Transform Dirac impulse with scaled argument
Currently, I am dealing with the sampling problems and I don't understand how to calculate inverse Fourier transform of a scaling impulse function
$\textrm{IFT}\{\delta(\Omega T)\} = ?$, $T$ is ...
-1
votes
2answers
70 views
How to get the inverse of Filter based on channel
Given a signal $X$, and a channel $h$, and the received signal $Y = Filter(h,1,X);$
What's the inverse of filter, it means if I know $h$, how can I get back $X$ ?
0
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0answers
23 views
Inversion problem for big dataset
Suppose my goal is to solve for $x$ in $Ax = b$ using CG method and $A$ is Toeplitz. The problem is that $b$ is extremely large in size and I can't just read in the whole vector $b$ and then solve for ...
0
votes
1answer
67 views
Inverse system of a box function
I learned about the inverse system.
Suppose I have an impulse response $h(t)$ which is a box function.
($A = 1, T = 2$)
If I take the Fourier transform and referring the transform pairs,
$$H(j\omega)...
0
votes
2answers
93 views
My impulse response does not tend to zero
I am doing an IFFT of frequency response data achieved with Simulation tools.
When I plot my impulse response it looks wrong as the response does not tend to zero as it should. Instead there seems ...
0
votes
2answers
237 views
Z transform - Inverse System function - Why number of poles and zeros myst be equal?
I know that if a system is causal then the system function H(z) must have :
a) a ROC that spans from the exterior of the most distant pole and
b) the number of zeros must not be greater than the ...
0
votes
0answers
36 views
is this system invertible?
Is this system invertible?
$$H \lbrace x(t) \rbrace = x(e^t) $$
I can find the reverse mapping from exp, but I'm not sure whether in systems theory this is considered reversible.
I'd love to get an ...
0
votes
1answer
53 views
How can I find the value of Inverse DFT
I have dt signal $x[n]={[6.29, 8.11,-7.46,8.26,2.64,-8.04,-4.43,0.93,-9.29]}$
And I need to give the function value of:
1) sum of $x[n] = \sum\limits_{k=0}^{N-1} X[k] \, e^{-j 3 \pi k/5}$ from k=0 ...
0
votes
1answer
347 views
Is the inverse of a causal system also causal?
If I have a causal system H(z) and I find the inverse of this system:
$$
G(z) = \frac{1}{H(z)}
$$
Is G(z) also causal?
1
vote
1answer
120 views
Problems with IFFT not being symmetrical
I have two signals, a measurement and a reference which I have performed an FFT on. They have both been windowed with a Hanning window, and now I would like to deconvolve these to get the impulse ...
0
votes
2answers
321 views
Is $y[n]=x[n] * x[n^2]$ invertible?
Is the following system invertible or not?
$$y[n]=x[n] * x[n^2]$$ where $*$ stands for the aperiodic convolution operator. I have not been able to find a mathematically sufficient argument for it...
0
votes
2answers
480 views
Inverse system of a system with integral
I am trying to find the inverse system of the following (I tried finding the mathematical inverse function but since it is not the same I am not so sure) . Can someone help me find it?
$$ y(t)=\int_{...
1
vote
0answers
54 views
Normalized LMS with a posteriori Error and Woodburry's Matrix Inversion
I was going through this paper and the author mentioned that we can prove the following using the Matrix Inversion Lemma (AKA Woodburry's Matrix Inversion Identity): Using matrix inversion lemma we ...
0
votes
1answer
320 views
Programming the IDWT for image processing
I want to program the 2D inverse discrete wavelet transform (only 1 level) in the case of image processing. In the matlab website there's this diagram:
now, I want to program the IDWT with haar ...
1
vote
2answers
1k views
Discrete time inverse fourier transform of cosine squared
$$ X(\omega) = \cos^2(\omega)$$
I tried this problem, and I ended up getting $0$, which doesn't make any sense. I integrated:
$$ x(n) = \frac{1}{2\pi}\int_{0}^{2\pi} \cos^2(\omega)e^{j{\pi}n} d\...
2
votes
1answer
653 views
Is this system invertible or not?
Prove that the following system is invertible.
$$y(t) = \mathcal{T}\{x(t)\} = \int_{-\infty}^{3t} x(\tau) \,\mathrm d \tau$$
Answer: yes, the system is invertible. I need some hint here, not the ...
