All Questions
Tagged with signal-processing frequency
49
questions
0
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1
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53
views
Is there any known result about the "average period" of a complicated oscillating function?
Say we have some frequency spectrum, $f(\omega)$, where
$$
f(t) = \frac{1}{2\pi} \int_{-\infty}^\infty d\omega \; f(\omega)e^{-i\omega t},
$$
and we know that $f(t)$ is some sort of ...
- 188
9
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2
answers
5k
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What is meant by 2D fourier transform of an image?
I have some questions about this interesting concept I came across about 2D Fourier transform, please...
Firstly, the Fourier transform of a 1D signal (such as a sound recording) is as follows:
The ...
user315366
1
vote
1
answer
43
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What is the relation between the frequency vector and the Nyquist frequency?
When trying to comprehend the concept of Nyquist frequency in FFT, I came across the following definition for half of the frequency range:
$$f = -f_{n}/2:df:f_{n}/2-1;$$
where $f$ represents the ...
- 753
1
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1
answer
166
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What is the meaning of the absolute of the Fourier transform in this context?
In a course talking about Fourrier transform and Nyquist frequency, there is this sentence that I can't understand:
"If a signal has $|F(w)| \geq 0$ only for frequencies till f, than such ...
- 113
1
vote
1
answer
96
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Can we decompose sound like white light is decomposed (dispersed) in different colors?
When we send white light through a prism, the light is decomposed in the colors that constitute it due to the different velocities which different frequencies. Is there a way to decompose "white ...
2
votes
2
answers
2k
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Amplitude based "filtering"
Standard filters in electronic circuits are devices that allow a certain range of frequencies to pass through while attenuate other frequencies. I was wondering if something similar could be built ...
- 484
14
votes
10
answers
8k
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Why does a capacitor act as a frequency filter?
What is it about a capacitor which allows it to filter frequencies?
I understand the construction of a high-pass RC filter, and the mathematics behind it, but I'm struggling to find an explanation of ...
- 267
1
vote
1
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141
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Intuitive explanation of Nyquist rate?
Is there an intuitive way to understand Nyquist rate (i.e., that, in order to prevent loss, an analog signal must be digitized at a rate twice as high as the highest frequency component of the signal)....
- 111
0
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1
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132
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Frequency of signal means changing or moving?
I saw some where frequncy means how fast a signal is changing and i am confused.
Since frequncy means how much cycle a signal completes in unit of time and we may say how fast a signal is moving but ...
- 17
0
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66
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In square wave modulation: should the low frequency part of the graph not take place in the low amplitude part of the pulse?
I try to get my sound program right, and hoped to find some help here with the understanding of frequency modulation by a square wave.
My modulation looks like this: (please excuse if my formula ...
- 101
0
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1
answer
2k
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Help in understanding frequency vs phase difference graph
The following graph in my textbook plots the relationship of external driving frequency and phase difference of the driver and a system. From this question (Why dosn't amplitude increase when ...
- 167
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1
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58
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Catching the beat! [closed]
I'm lately fascinated with the whole "beat" concept, and have been doing some experiments. I'm trying to capture the beat waveform on an oscilloscope in run mode, but am having no luck. I'm putting a ...
- 13
2
votes
0
answers
86
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The validity of some "applications" of the uncertainty principle
Given a $L^2$ function $f$ with $\int_\mathbb{R}xf(x)dx=0$, define its variance to be $\sigma_f^2=\int_{\mathbb R}x^2f(x)dx$. The uncertainty principle states that $\sigma_f\sigma_\hat f\geq 1/4\pi$,...
- 1,335
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59
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"Synchronization" Probability of Multiple Waves with Varying Frequencies
Update 1: I've done some digging and I think this is related to signal coherence, namely, that I'm seeing a coherence time of ~3 σ, which is consistent with the definition where Ct=1/Δv where Δv is ...
- 287
1
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2
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318
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Why we use Nyquist frequency limits
Can someone in simple terms why you would use Nyquist frequency limits when processing a signal? What benefit does it provide, and how does it affect the results? And how does it relate to the Nyquist ...
- 125