Questions tagged [sinc]
The sinc tag has no summary.
59 questions
2 votes
3 answers
2k views
Explanation of an Irregular Webcomic DSP joke
Irregular Webcomic! #1640 is a parody of an xkcd comic. I heard of this comic from the 2019-02-01 recording of UC Berkeley EE123 class, but it didn't give a detailed explanation. It was after the ...
- 23
1 vote
1 answer
75 views
Fourier Transform of a squared sinc function in R^d
Is it possible to find the Fourier Transform of $\textrm{sinc}^{2}$ in $\mathbb{R}^{\textrm{d}}$ if we use the distribution sense?
2 votes
0 answers
76 views
Simplifications of 3x sinc downsampling
Today I resampled a signal by a factor of 3, i.e. from $3 \cdot f_s$ to $f_s$, using a sinc filter and decimation. Then it occurred to me that there is some room for optimisation there, but I didn't ...
- 2,453
3 votes
2 answers
295 views
Why we can't implement an ideal digital filter in the frequency domain and then anti-transform?
It is well known that a digital ideal low pass filter is not feasible since in frequency domain it's a rect function and in the time domain a sinc, which extends infinitely along the entire time axis ...
0 votes
0 answers
49 views
Question on frequency sampling from Coursera DSP class 2.2.1c
In this video (from 2:00), it talks about why frequency sampling is a bad idea: https://www.coursera.org/learn/dsp2/lecture/0QKiE/2-2-1-c-frequency-sampling But I am not able to understand the details ...
- 45
1 vote
1 answer
135 views
The Discrete Fourier Transform (DFT) Pair of Rectangular / Indicator Function
I'm trying to properly understand the fft and tired to recover the sinc function from its Fourier transform, i.e. an indicator ...
- 59
4 votes
1 answer
449 views
A new window for the sinc filter and its modifications
There is a recent paper in a journal called ACS Measurements which suggests an alternative window for the sinc function (Why and How Savitzky–Golay Filters Should Be Replaced) Link: Open Access Paper. ...
- 704
0 votes
1 answer
122 views
Convolution with the Inverse FFT of a Box Filter
I read through this post here on an example of filtering using the box function in fourier space. The example makes sense and I was able to follow it and implement it in Julia (I did in space instead ...
- 103
4 votes
1 answer
193 views
Best Methods for Interpolating Short Non-Periodic Bandlimited Signals
I need advice on interpolating a very short (N < 10) discrete, bandlimited signal that is sampled above the Nyquist rate. I understand that technically finite length signals have infinite bandwidth,...
- 2,713
4 votes
0 answers
256 views
What are the advantages of using the Dirichlet kernel for interpolation?
Suppose we define the Dirichlet kernel as: $$ \frac{\sin(\pi N x /2)}{N\sin(\pi x /2)} $$ (Note: I'm not entirely sure what the standard definition of the Dirichlet kernel is; mine is slightly ...
- 2,713
1 vote
1 answer
147 views
Signal recovery is based on the development of the Shannon sampling theorem?
One of the earliest extensions of this theorem was stated by Shannon himself in his 1949 paper, which says that if $x(t)$ and its first $(M - 1)$ derivatives are available, then uniformly spaced ...
- 11
2 votes
1 answer
76 views
Digital Audio Resampling
I've been working from this reference document, essentially trying to recreate Figure 7 with the understanding that the two functions place_signal and ...
1 vote
2 answers
114 views
Since harmonics only generate at multiples of the center freq, is it for this reason that the left part of a FT (like sinc) has no physical meaning?
If we have a rectangular pulse function, we know that after a Fourier transform we obtain a sinc: We know that the left part (negative frequencies) has no physical meaning and it's just specular. It'...
- 125
15 votes
4 answers
4k views
Why is the time domain low-pass filter the "sinc" shape?
Consider: I'm looking at low-pass filters, and I see that the time domain representation of an "ideal" filter resembles the shape above whereas the frequency domain is a box. I also get the ...
- 153
0 votes
1 answer
234 views
Filtering in time domain vs filtering in frequency domain
The signal is an impulse repsonse. I am filtering the signal using a windowed sinc filter in both frequency and time domain. I am interested in knowing the differences between the two methods and ...
