Difference between revisions of "Sinc"

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File:Sinc.png|Plot of $\mathrm{sinc}$ on $[-15,15]$.
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File:Sincplot.png|Plot of $\mathrm{sinc}$ on $[-15,15]$.
 
File:Complexsincplot.png|[[Domain coloring]] of $\mathrm{sinc}$.
 
File:Complexsincplot.png|[[Domain coloring]] of $\mathrm{sinc}$.
 
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=Properties=
 
=Properties=
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[[Sum of values of sinc]]<br />
<strong>Theorem:</strong> The following formula holds:
 
$$\mathrm{sinc}(x)=\displaystyle\prod_{k=1}^{\infty} \cos \left( \dfrac{x}{2^k} \right).$$
 
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<strong>Proof:</strong> █
 
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{{:Sum of values of sinc}}
 
 
 
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<strong>Theorem:</strong> The following formula holds:
 
$$\displaystyle\sum_{k=1}^{\infty} (-1)^{k+1}\mathrm{sinc}(k)=\dfrac{1}{2}.$$
 
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<strong>Proof:</strong> █
 
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=Videos=
 
=Videos=
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[https://www.youtube.com/watch?v=xx2AQz_ZyC0 Integrating the sinc function]<br />
 
[https://www.youtube.com/watch?v=xx2AQz_ZyC0 Integrating the sinc function]<br />
  
<center>{{:*-c functions footer}}</center>
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=See also=
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[[Normalized sinc]]<br />
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[[Category:SpecialFunction]]
 
[[Category:SpecialFunction]]

Latest revision as of 02:19, 16 September 2016

The $\mathrm{sinc}$ function (sometimes called the "unnormalized" $\mathrm{sinc}$ function) is defined by $$\mathrm{sinc}(z) = \left\{ \begin{array}{ll} \dfrac{\sin z}{z} &; z \neq 0 \\ 1 &; z=0. \end{array} \right.$$ It appears in the definition of the Sine integral function.

Properties

Sum of values of sinc

Videos

Infinite Product Evaluation with the Sinc Function
(The Sinc Function) Inverse Fourier Transform of Sinc & Fourier Transform of Sinc
Fourier Transform of a Sinc Function (or Inverse Fourier Transform of a Low Pass Filter)
Discrete-Time Signals and Systems Introduction (4/6): Special Functions
Integrating the sinc function

See also

Normalized sinc

$*$-c functions