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# Questions tagged [transform]

In signal processing, a transform is a mathematical technique to convert data in one domain to another. The most common example is using the Fourier Transform to convert data from the time domain to the frequency domain.

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### How does the shape of a frequency domain function (Fourier Transformed time domain function) change when a time shift is applied in the time domain?

When there is a time shift (or delay) in the time domain on a function, the Fourier transform gets multiplied by an exponential which corresponds to a phase shift on the original frequency domain ...
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### Effect of overlapping percentage on STFT output

I know STFT is generally applied to non-stationary signals but I tried to apply it to a stationary signal to get a working knowledge. I created a stationary signal composed of three frequencies as ...
326 views

### Calculating signal power from Continuous Wavelet Transform in MATLAB

I would like to ask a question about the calculation of the signal power using CWT in Matlab. Assume a signal of length N points with sampling frequency $f_{s}$. Using conventional approach, the power ...
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1 vote
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### Given the Fourier Transform of a continuous signal how can I sketch the sampled signals discrete time fourier transform

I am given the frequency response for a continuous time signal $X(j\omega)$ = 2 at $\omega=0$ and 0 at $\omega = -10000\pi$ and $10000 \pi$. Looks like a triangle. I am told to sketch $X(e^{jw})$ ...
562 views

### Bandwidth of a given function

Suppose the signal given is $x(t)=(cos(5t)+e^{-2t})u(t)$ and the goal is to find the bandwidth of this signal. We know the bandwidth, $B$, is just $f_{max}-f_{min}$. Our first step is taking the ...
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### What is "Drift" in context of transformation concatenation?

My lecturer talked about transformation concatenation and he mentioned the "Drift" problem and that "bundle adjustment" may solve it. Since I could not find any information on it ...
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1 vote
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### How to convert a line that goes through the origin into Hough space?

Assume that the lines are parameterized with an angle $\theta$ of the line normal and a distance $\rho$ from the origin: For each of the lines in the image space below (left), draw the corresponding ...
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1 vote
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### 2D Fourier transform over mask of an image

I have an image, which has an inherent mask built into it. The exact shape isn't super important, but it looks something like a circ multiplied by a rect. I would like to calculate the 2D Fourier ...
1 vote
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### How do i compare the compression of different transforms?

I have to compare the compression capacity of different transformations on the same signal. The explanations were very brief, but i have to compare some energy thresholds(e.g. 50% of the total energy) ...
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### How can we prove the correctness of the integration property of the Laplace transform?

I was going through an Electrical Engineering textbook for understanding the Laplace transform and came across the following proof for one of the properties of the Unilateral Laplace transform. ...
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### Phase shift of discrete cosine transform (DCT)

The most common type of discrete cosine transform (DCT-II) is defined as \begin{align} X_k&=\sum_{n=0}^{N-1}x_n\cdot \cos\left(\frac{\pi}{N}\left(n+\frac{1}{2}\right)\cdot k\right)&\text{where ...
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### multiplication of a function with a Fourier-transformed equals to Fourier-transformed with a function

I already showed b item using the fact that it is $h\left(0\right)=\int \:f\left(t\right)g\left(0-t\right)dt$ I struggle a lot of hours trying to find the trick in item C. Can anyone help please ?
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### even symmetry of magnitude and odd symmetry of phase [closed]

I'll appreciate it if any of you guys could help me with this question: Suppose that x(t) is a real signal, prove that the magnitude of its Fourier transform has even symmetry and its phase has odd ...
1 vote
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### How to test wavelet transforms?

One pertinent attribute is normalization, which measures performance in describing signal spectral amplitude and energy, like here. Others are robustness to noise, time vs frequency resolution. ...
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### Why does MATLAB's dualtree3 function not return the lowpass subband of the imaginary tree?

MATLAB has a function named dualtree3 which computes 3-D dual-tree complex wavelet transform. This function only retains the last low-pass coefficients/subband of ...
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