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1500 questions
13
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1 answer
How does ICA handle inevitable delays in signals?
I am currently reading up on and teaching myself ICA from a number of good sources. (Also see this post for past context). I have the basic jist down, but there is something I am not clear about.
For a scenario where multiple signals are impinging…
Spacey
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12
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5 answers
Radix-4 FFT versus Radix-2
Is a radix-4 implementation faster than a equivalently well coded radix-2 FFT? And if so, why would it be faster?
hotpaw2
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12
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How does adaptive Huffman coding work?
Huffman coding is a widely used method of entropy coding used for data compression. It assumes that we have complete knowledge of a signal's statistics. However, there are versions of Huffman coding that are used with streaming media and cannot…
Phonon
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12
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3 answers
How do I get started with Wavelets
Our current project requires us to do some analysis using Wavelet Transform. Can anybody suggest me a practical book, preferably with MATLAB or C examples.
I am currently reading some tutorials, but it is not giving me a feeling as I have for…
gpuguy
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12
votes
3 answers
Can we have a Digital Anti Aliasing filter?
I am working on a board that has no antialisaing filter at the input of the ADC. I have option to I implement my own filter using RC + Opamp circuit. But is it also possible to implement Anti Aliasing filter after sampling by ADC and processing in…
gpuguy
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12
votes
2 answers
Centering zero frequency for Discrete Fourier Transform
I am working on a image processing application which uses a discrete fourier transform to implement blurring/sharpening. The application is more or less working, but something about the mechanics is still confusing to me.
In particular, it is how…
dizzy
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12
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1 answer
Is there a relation between an analytic signal (signal processing) and an analytic function (complex analysis)?
In signal processing, we define an analytic signal as a complex-valued signal which has no frequency components for $\omega<0$. It can be shown that the real part and the imaginary part of an analytic signal $x(t)=x_R(t)+jx_I(t)$ are related by the…
Matt L.
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12
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2 answers
Where are these aliasing artifacts coming from in transmitting audio? (Frequency reflection, duplication)
I am trying to understand how a SIM7600G 4G modem degrades the audio when configured for 8 kHz sampling rate. I created a reference audio using librosa.chirp to slowly sine sweep from 30 Hz to 3400 Hz. I saved the raw audio using 8 kHz sampling…
Peter
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12
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3 answers
Other end of Nyquist limit
Say I perform FFT on some data. If the underlying (measurement) sampling rate is not twice the highest frequency, I will almost assuredly get aliasing.
This limit on sampling we call the Nyquist limit. Now on the flip side, if the integration…
Davey
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12
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5 answers
Introduction to Statistical Signal Processing
There is a postdoc in my lab whose specialty is "statistical signal processing". He has a PhD in Electrical Engineering and he analyzes the neural data collected.
I am wondering what courses/topics I should start studying to follow in his footsteps.…
Diego
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12
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2 answers
What is the maximum possible frequency of human voice/speech(That can be generated through human vocal cords)?
Human hearing range is commonly known to be 20 Hz to 20 KHz
But what about speaking range? We know that speech Sounds are generated through our vocal cords. So What is the maximum value of frequency that human speech can have?
DSP_CS
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12
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5 answers
What is the frequency representation of nonuniform sampling?
Uniform sampling can be thought of as multiplication of a function $x(t)$ with a Dirac comb function: $$\text{III}_T(t) = \sum_{k=-\infty}^{\infty}\delta(t-kT)$$
Multiplication of $x(t)$ with $\text{III}_T(t)$ is equivalent to convolution with…
Gillespie
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12
votes
4 answers
Universal Bases (Dictionary) for Image Compression
I am a physics graduate student working on a data compression problem. I have been reading Prof. Steven L. Brunton's book on data driven science and engineering.
I am fascinated to the concept of sparsity of images/signals. Prof. Brunton claims that…
Ricky Pang
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12
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1 answer
Reconstructing Tree Limbs that are Occluded by Leaves
How would would one approximately reconstruct the branches in a photo of a tree, where portions of the branches are covered by leaves?
I can extract the visible portions of the branches by threshholding then opening with line segments at a few…
Martin
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12
votes
4 answers
Fastest way to compute Arctan2 on an FPGA
Rip Van Winkle here -- is the fastest and least-footprint way to compute an arctan on an FPGA still to use CORDIC?
Or is there a way to leverage block RAM and DSP blocks to speed and/or reduce the size of the process?
TimWescott
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