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1500 questions
8
votes
3 answers
Determining Type and Bandwidth of a filter
Given a filter, if it is given as an equation such as:
$$f(x,y) = \left(\frac{\partial^2}{\partial x^2} + \frac{\partial^2}{\partial y^2}\right) \exp\left(-\frac{x^2 + y^2}{\sigma^2}\right)$$
Or in a kernel such as:
$$
\left[\begin{array}{rrr}
0 & 1…
Peter
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8
votes
1 answer
Problem with the definition of Linearity
From the high school maths we know that y=mx+c is a linear equation. However, in DSP the linear system must satisfy Additivity properties which y=mx+c does not hold because of +c.
So, is the definition of Linearity different in DSP and Maths? if so…
Zahid Hasan
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8
votes
5 answers
What are some methods for detecting a sinusoid in noise?
I'm looking for a broad classification on the kinds of techniques available. Something I can use to begin a literature survey.
Some details:
should be feasible for real-time implementation.
Binary decision, I should be able to input the signal…
ankit
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8
votes
1 answer
How to send / receive a short impulse in an extremely noisy signal with high timing accuracy?
I am pretty new to DSP. I need a computer to transmit data to a receiver through audio signals in a loud outdoor environment. (I am writing the software for both sender and receiver so I can design the signal however I want.) I am using cheap…
Keith
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8
votes
1 answer
Speech comparison algorithm for rating on similarities
I am trying to compare 2 speech samples and rate them on similarities. Think of someone trying to repeat a phrase, and then comparing those 2 audio files.
I started by implementing the MFCC (http://en.wikipedia.org/wiki/Mel-frequency_cepstrum)…
YoungMoney
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8
votes
3 answers
Common methods of transmitting digital data through an extremely noisy audio signal?
I am developing software for transmitting data from a computer to a mobile device using audio. Specifically, from the computer's speaker to the device's microphone. (I am developing both the sender and the receiver software.) This is one channel,…
Keith
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8
votes
5 answers
What is really the Mel-filterbank?
After applying STFT to a signal, you typically need to convert the frequencies to the Mel scale. Typically the frequency values range from $0$ to $N/2$, where $N$ is the width of each sliding window.
I have read so many articles about Mel…
Francesco Ladogana
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8
votes
4 answers
Deconvolution to Remove Gaussian Blur in 1D Signal (Wiener Filtering?)
I've got a set of biology data that I'm trying to denoise (effectively, a population statistic can only be measured convolved with a gaussian of known width)
My problem is this: I can measure (f*g), and I can measure g(x), but I need to know f(x).…
Abe Pressman
- 81
- 3
8
votes
5 answers
Estimation of Amplitude, Frequency and Phase of Linear Combination of Harmonic Signal Beyond the Leakage Resolution of DFT
How can I find a rough ( as accurate as possible) Amplitude of each frequency when there is spectral leakage.
Currently, I am dealing with a system that contains special leakage which seems unavoidable as I am measuring a real signal with any…
Jacob wood
- 141
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8
votes
1 answer
The Proper Way to Do Sinc Downsampling (DFT Downsampling) for Uniformly Sampled Discrete Signals with Finite Number of Samples
Given a discrete signal $ \left\{ x [ 0 ], x [ 1 ], \ldots, x [ N - 1 ] \right\} $ what would be the correct way to downsample it in the frequency domain (Sinc interpolation)?
David
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8
votes
5 answers
How can I upsample 22 kHz speech audio recording to 44 kHz, maybe using AI?
I have a 22 kHz mono audio recording, which is mainly speech, a reading. I would like to upsample somehow to 44 kHz, to improve the audible quality. I have read about there are AI methods for upsampling pictures, even videos to a higher resolution.…
Konstantin
- 181
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8
votes
4 answers
the $L^2$-norm of a signal is also applied as its energy!
I am a newcomer in signal processing. I saw that the $L^2$-norm of a signal is also applied as its energy! How is this concept illustrated for those ones who are working in pure math.
ABB
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8
votes
2 answers
Why are there comb-like hills in a periodogram?
I am playing with the periodogram of MATLAB. I created a simple script to observe how it behaves:
rng(1); %# initialize the random number generator
Fs = 1000; %# Sampling frequency
duration = 0.1; %# seconds
A = 1; %# Sinusoid amplitude
f = 150;…
petrichor
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8
votes
3 answers
Quantization SNR of sine wave doesn't match 1.761 + 6.02 * Q
I am trying to show with numpy that the quantization noise of a sine wave matches the SNR formula of SNR = 1.761 + 6.02 * Q.
The numpy code is simple:
import numpy as np
import matplotlib
from matplotlib import pylab, mlab, pyplot
plt =…
Tom Verbeure
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8
votes
1 answer
How is the Laplacian used for Unsharp Mask?
Some unsharp algorithms (e.g. Matlab's fspecial) use a Laplacian kernel to achieve sharpening of the image.
From what I know, the image needs to be blurred first, and then the blurred image is subtracted from the original to get a sharper image. The…
Michael Litvin
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