Signal Processing Stack Exchange
Signal Processing Stack Exchange

Most Popular

more tags
1500 questions
9
votes
2 answers

Physical Meaning of Negative Group Delay for causal LTI systems

I have implemented in Matlab (with minor variations) the example 5.1.2 "Illustration of Effects of Group Delay and Attenuation" I found in Alan Oppenheim's Discrete-Time Signal Processing 3rd edition. In this example, 3 narrow band signals (high…
VMMF
  • 1,090
  • 1
  • 12
  • 23
9
votes
5 answers

Does windowing affect Parseval's theorem?

I have computed Fourier transform from ecg data.It does obey Parseval's theorem, relation $$\sum_{n=0}^{N-1} \Big| x[n] \Big|^2 = \frac{1}{N} \sum_{k=0}^{N-1} \Big| X[k] \Big|^2$$ is fulfiled. But after I use window function…
wiedzminYo
  • 193
  • 1
  • 4
9
votes
1 answer

limit to possible noise shaping?

I want to do noise shaping in a 100kHz, 16 bit application, so as to shift all quantization noise to the 25khz-50kHz band, with minimal noise in the DC-25kHz band. I set up mathematica to create a 31-sample error filter kernel via reinforcement…
tobalt
  • 468
  • 2
  • 12
9
votes
2 answers

How to detect continuous noise in audio call?

We want to detect bad audio quality in audio call. Should we extract this information from amplitude or frequency spectrum ? Is there any technique/transform/filter available for this ? Example: I am attaching two signal graph(Clean Signal vs Noisy…
user31281
  • 91
  • 2
9
votes
2 answers

Compressive Sensing vs. Sparse Coding

There apparently are different terminologies used to refer to the same field called "compressive sensing" such as (see this wiki page): compressed sensing, compressive sampling, or sparse sampling. I wonder about "sparse sensing"…
Learn_and_Share
  • 458
  • 2
  • 9
9
votes
4 answers

Is the Dirac delta (impulse) signal a power signal or an energy signal?

I'm a beginner so sorry if this question is very fundamental. Dirac impulse has finite area i.e = 1. But I've heard that $|\delta(t)|^2$ is undefined. So area under $|\delta(t)|^2$ is also undefined and signal doesn't exist in all time $t$ so it…
Hendry Newman
  • 93
  • 1
  • 1
  • 5
9
votes
2 answers

When and how does one use a Wiener filter?

I'm trying to get some insight in this topic. As far as I understand, a determined signal enters a Wiener filter and the output is an estimate of some desired signal. Then, one can substract the desired signal to the output of the filter and…
Tendero
  • 5,020
  • 6
  • 27
  • 46
9
votes
3 answers

Fourier Transform Identities

We know the below, $$ \mathscr{F}\big\{x(t)\big\}=X(f) \tag{1} $$ $$ \mathscr{F}\big\{x(-t)\big\}=X(-f) \tag{2} $$ $$ \mathscr{F}\big\{x^*(t)\big\}=X^*(-f) \tag{3} $$ Now, if for some signal $$ x(-t)=x^*(t) \tag{4} $$ Then, is it safe to assume the…
sundar
  • 343
  • 5
  • 25
9
votes
3 answers

Why is not Fourier Transform Good for Non-linear Processes

I was reading through slides about Hilbert Huang Transform. In slide 14, which talks about the motivations of a new method instead of Fourier Transform (FT), the author provides those two reasons in addition to other reasons Physical processes are…
hbak
  • 321
  • 1
  • 3
  • 10
9
votes
2 answers

Why do we need 4 points for homography but 7/8 points for fundamental matrix calculation?

Sorry if this is a trivial question but I could not find a suitable answer elsewhere. I recently learned about homography and fundamental matrices in a CV class. I understand how these matrices are calculated and how the the formulae are derived. I…
Monster
  • 203
  • 2
  • 6
9
votes
1 answer

Quantization Noise for Coherent Sampling - Phase Noise?

Update: See added thoughts at bottom of this post. Under general sampling conditions not constrained by what is described below (signal uncorrelated to sampling clock), quantization noise is often estimated as a uniform distribution over one…
Dan Boschen
  • 50,942
  • 2
  • 57
  • 135
9
votes
2 answers

Zero Phase Filter: Determining Initial Conditions for Forward Backward Filtering

Is anybody familiar with Gustafson's algorithm for minimizing transients in forward backward filtering [1]? I'm trying to implement it and my first guess was to check Matlab's filtfilt.m, since they are referencing the paper. In the Matlab function…
user967493
  • 387
  • 2
  • 12
9
votes
5 answers

IIR Hilbert Transformer

I'm beginning to explore discrete Hilbert transformers - ways to achieve 90°. phase shift across a band of perhaps 6 kHz at a 44.1 kHz sampling rate. I'm trying to stick with IIR filters in order to save computation time - in addition to the fact…
Robby Wasabi
  • 331
  • 2
  • 7
9
votes
3 answers

Why do linear phase filters have symmetric impulse responses?

It was given as a fact that linear phase filters have symmetric impulse responses, but I don't see why that has to be true. Can somebody please explain or prove this?
CAJ
  • 313
  • 2
  • 7
9
votes
1 answer

Correlation : How is correlation analogous to dot product?

Till now I know correlation tells about similarity. I was watching a video lecture on image similarity in which I came to know that correlation is analogous to dot product. And hence correlation of two images is maximum when these images are similar…
No Sound
  • 171
  • 1
  • 2
  • 10
1 2 3
…
99 100