Most Popular
1500 questions
7
votes
3 answers
Why integrate over $2\pi$ in inverse DTFT?
In DTFT of a signal, the spectrum of a sequence is periodic with period $2\pi$ and all the information needed for derivation of the original signal from its spectrum is contained in $\pi <\omega <\pi$.
But , why do they integrate over $2\pi$ and not…
Zorich
- 171
- 5
7
votes
1 answer
MFCC feature extraction
I have a block of audio and I have performed an FFT on it. Now what I want to do is convert this FFT into a set of MFCCs, however while I know I need to do something with weighting the FFT samples based upon a set f triangular filters I haven't…
Goz
- 475
- 1
- 9
- 21
7
votes
1 answer
Conditions for unique (not exact) recovery from noisy compressed measurements
I am looking for theory on whether compressed sensing reconstruction via ℓ1-minimization is unique and under which conditions.
I have looked through:
Tropp, J. A., "Just relax: convex programming methods for identifying sparse signals in noise,"…
Thomas Arildsen
- 1,322
- 7
- 17
7
votes
3 answers
Why use an ARMA process theory instead of just performing linear regression?
I am studying ARMA processes. At the end of the course the professor told us that estimating the next sample in an arma process using past of length $p$ (so performing a projection of $X_t$ on $\text{span}(X_{t-1}, ..., X_{t-1-p})$ is the same as…
Robert Laplace
- 71
- 1
7
votes
1 answer
What window functions allow for controlling the location of nulls?
Window functions are commonly used to control spectral sidelobes. Typically there is a trade between supressing sidelobes, and maintaining the resolution of the mainlobe. A window with lower sidelobes has a wider mainlobe.
But another characteristic…
Gillespie
- 1,767
- 4
- 26
7
votes
1 answer
How Exactly Does MATLAB Zero Pad Signal?
I am doing some massive number crunching in MATLAB which involves millions of PSD estimations. Each data segment has length 41. So I have been using the multi-taper method with nfft=41 (details below in the code). My last simulation took more than…
Fixed Point
- 379
- 1
- 4
- 8
7
votes
2 answers
If the convolution of two signals is a unit impulse, what does this tell us?
I have two discrete-time LTI systems whose transfer functions satisfy $h_1[n] * h_2[n]= \delta[n]$. We also know that system 1 is causal and stable. Does $h_1[n] * h_2[n]= \delta[n]$ tell us anything about $h_2$?
Intuitively, I would say that…
tonythestark
- 249
- 1
- 9
7
votes
2 answers
Estimating Plane Pose Without Knowledge of Intrinsic Camera Parameters
Assume a camera has no skew, and has square pixels, that is, its camera-calibration matrix, $K$, looks like:
$$
K = \left[\begin{matrix} \alpha&0&u_x\\0&\alpha&u_y\\0&0&1 \end{matrix}\right]
$$
Intuitively, it seems that it should be possible to…
Joey
- 71
- 3
7
votes
3 answers
Determining the mean of of a sampled signal (improvements to time averaging method)
I am sampling a signal at 1kHz, which is essentially a single-frequency sinusoid with a DC offset (and a small amount of noise). I don't know the precise frequency of the sinusoid (it is at most 10Hz), and I want to record the mean value of the…
Edward
- 71
- 2
7
votes
14 answers
What would be an example of something digital which isn't electronic?
The terms digital and electronic are often used interchangeably but I know that it's not correct because something can be digital but not electronic.
Something can be digital in the sense that it's discrete both in time and magnitude.
A picture of a…
somo
- 73
- 1
- 4
7
votes
1 answer
Noise leakage problem with least square estimation in the frequency-distance domain
I have data $d$ recorded from an antenna of sensors. These data are composed of a Gaussian noise $n$ and a signal $s$ which I try to estimate. This signal propagates on the antenna with frequency dependent attenuation and velocity. Below is an…
User327201
- 85
- 8
7
votes
2 answers
What is the difference between a simple gaussian filter and gaussian filter multiplied by its sum of it elements?
1 2 1 1 2 1
2 4 2 (A) (1/16) * 2 4 2 (B)
1 2 1 1 2 1
Both matrices are the same except that the matrix B is multiplied by the sum of its elements.
When convolved with…
Animesh Pandey
- 457
- 1
- 6
- 12
7
votes
2 answers
Estimation of the Amplitude of a Sine / Cosine Wave and Its Independence of the SNR / Amplitude of the Wave
Consider a sinusoid in AWGN:
$$Y = A \cos(\omega t+\phi)+n $$
Assume the frequency and phase are known. To estimate $A$ we can use least squares (which in this case is equivalent to the DFT):
$\hat{A} = (H’H)^{-1}H’Y$
where $H$ is the design matrix…
student1
- 384
- 6
- 16
7
votes
4 answers
Building a data acquisition system to capture raw IQ data
I was planning to build a data acquisition system to capture raw IQ data for a hobby project and the short-term goal is to gain practical experience on RF front ends and ADC's.
My background is mostly Wireless DSP implementations in MATLAB/C (and…
Farheen Shaik
- 73
- 4
7
votes
1 answer
Why Is PDE Based Image Processing Not as Active as It Used to Be?
I can see from the literature that PDE-based image processing (especially inpainting) was a "hot topic" at one point. Why does it not seem to be an active area of research anymore, yet it looks like there are many unanswered seemingly important…
KaRJ XEN
- 123
- 5