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Raised cosine distribution

From Wikipedia, the free encyclopedia
Probability distribution
Raised cosine
Probability density function
Plot of the raised cosine PDF
Cumulative distribution function
Plot of the raised cosine CDF
Parameters

μ {\displaystyle \mu ,円} {\displaystyle \mu ,円}(real)

s > 0 {\displaystyle s>0,円} {\displaystyle s>0,円}(real)
Support x [ μ s , μ + s ] {\displaystyle x\in [\mu -s,\mu +s],円} {\displaystyle x\in [\mu -s,\mu +s],円}
PDF 1 2 s [ 1 + cos ( x μ s π ) ] = 1 s hvc ( x μ s π ) {\displaystyle {\frac {1}{2s}}\left[1+\cos \left({\frac {x-\mu }{s}},円\pi \right)\right],円={\frac {1}{s}}\operatorname {hvc} \left({\frac {x-\mu }{s}},円\pi \right),円} {\displaystyle {\frac {1}{2s}}\left[1+\cos \left({\frac {x-\mu }{s}},円\pi \right)\right],円={\frac {1}{s}}\operatorname {hvc} \left({\frac {x-\mu }{s}},円\pi \right),円}
CDF 1 2 [ 1 + x μ s + 1 π sin ( x μ s π ) ] {\displaystyle {\frac {1}{2}}\left[1+{\frac {x-\mu }{s}}+{\frac {1}{\pi }}\sin \left({\frac {x-\mu }{s}},円\pi \right)\right]} {\displaystyle {\frac {1}{2}}\left[1+{\frac {x-\mu }{s}}+{\frac {1}{\pi }}\sin \left({\frac {x-\mu }{s}},円\pi \right)\right]}
Mean μ {\displaystyle \mu ,円} {\displaystyle \mu ,円}
Median μ {\displaystyle \mu ,円} {\displaystyle \mu ,円}
Mode μ {\displaystyle \mu ,円} {\displaystyle \mu ,円}
Variance s 2 ( 1 3 2 π 2 ) {\displaystyle s^{2}\left({\frac {1}{3}}-{\frac {2}{\pi ^{2}}}\right),円} {\displaystyle s^{2}\left({\frac {1}{3}}-{\frac {2}{\pi ^{2}}}\right),円}
Skewness 0 {\displaystyle 0,円} {\displaystyle 0,円}
Excess kurtosis 6 ( 90 π 4 ) 5 ( π 2 6 ) 2 = 0.59376 {\displaystyle {\frac {6(90-\pi ^{4})}{5(\pi ^{2}-6)^{2}}}=-0.59376\ldots ,円} {\displaystyle {\frac {6(90-\pi ^{4})}{5(\pi ^{2}-6)^{2}}}=-0.59376\ldots ,円}
MGF π 2 sinh ( s t ) s t ( π 2 + s 2 t 2 ) e μ t {\displaystyle {\frac {\pi ^{2}\sinh(st)}{st(\pi ^{2}+s^{2}t^{2})}},円e^{\mu t}} {\displaystyle {\frac {\pi ^{2}\sinh(st)}{st(\pi ^{2}+s^{2}t^{2})}},円e^{\mu t}}
CF π 2 sin ( s t ) s t ( π 2 s 2 t 2 ) e i μ t {\displaystyle {\frac {\pi ^{2}\sin(st)}{st(\pi ^{2}-s^{2}t^{2})}},円e^{i\mu t}} {\displaystyle {\frac {\pi ^{2}\sin(st)}{st(\pi ^{2}-s^{2}t^{2})}},円e^{i\mu t}}

In probability theory and statistics, the raised cosine distribution is a continuous probability distribution supported on the interval [ μ s , μ + s ] {\displaystyle [\mu -s,\mu +s]} {\displaystyle [\mu -s,\mu +s]}. The probability density function (PDF) is

f ( x ; μ , s ) = 1 2 s [ 1 + cos ( x μ s π ) ] = 1 s hvc ( x μ s π )  for  μ s x μ + s {\displaystyle f(x;\mu ,s)={\frac {1}{2s}}\left[1+\cos \left({\frac {x-\mu }{s}},円\pi \right)\right],円={\frac {1}{s}}\operatorname {hvc} \left({\frac {x-\mu }{s}},円\pi \right){\text{ for }}\mu -s\leq x\leq \mu +s} {\displaystyle f(x;\mu ,s)={\frac {1}{2s}}\left[1+\cos \left({\frac {x-\mu }{s}},円\pi \right)\right],円={\frac {1}{s}}\operatorname {hvc} \left({\frac {x-\mu }{s}},円\pi \right){\text{ for }}\mu -s\leq x\leq \mu +s}

and zero otherwise. The cumulative distribution function (CDF) is

F ( x ; μ , s ) = 1 2 [ 1 + x μ s + 1 π sin ( x μ s π ) ] {\displaystyle F(x;\mu ,s)={\frac {1}{2}}\left[1+{\frac {x-\mu }{s}}+{\frac {1}{\pi }}\sin \left({\frac {x-\mu }{s}},円\pi \right)\right]} {\displaystyle F(x;\mu ,s)={\frac {1}{2}}\left[1+{\frac {x-\mu }{s}}+{\frac {1}{\pi }}\sin \left({\frac {x-\mu }{s}},円\pi \right)\right]}

for μ s x μ + s {\displaystyle \mu -s\leq x\leq \mu +s} {\displaystyle \mu -s\leq x\leq \mu +s} and zero for x < μ s {\displaystyle x<\mu -s} {\displaystyle x<\mu -s} and unity for x > μ + s {\displaystyle x>\mu +s} {\displaystyle x>\mu +s}.

The moments of the raised cosine distribution are somewhat complicated in the general case, but are considerably simplified for the standard raised cosine distribution. The standard raised cosine distribution is just the raised cosine distribution with μ = 0 {\displaystyle \mu =0} {\displaystyle \mu =0} and s = 1 {\displaystyle s=1} {\displaystyle s=1}. Because the standard raised cosine distribution is an even function, the odd moments are zero. The even moments are given by:

E ( x 2 n ) = 1 2 1 1 [ 1 + cos ( x π ) ] x 2 n d x = 1 1 x 2 n hvc ( x π ) d x = 1 n + 1 + 1 1 + 2 n 1 F 2 ( n + 1 2 ; 1 2 , n + 3 2 ; π 2 4 ) {\displaystyle {\begin{aligned}\operatorname {E} (x^{2n})&={\frac {1}{2}}\int _{-1}^{1}[1+\cos(x\pi )]x^{2n},円dx=\int _{-1}^{1}x^{2n}\operatorname {hvc} (x\pi ),円dx\\[5pt]&={\frac {1}{n+1}}+{\frac {1}{1+2n}},円_{1}F_{2}\left(n+{\frac {1}{2}};{\frac {1}{2}},n+{\frac {3}{2}};{\frac {-\pi ^{2}}{4}}\right)\end{aligned}}} {\displaystyle {\begin{aligned}\operatorname {E} (x^{2n})&={\frac {1}{2}}\int _{-1}^{1}[1+\cos(x\pi )]x^{2n},円dx=\int _{-1}^{1}x^{2n}\operatorname {hvc} (x\pi ),円dx\\[5pt]&={\frac {1}{n+1}}+{\frac {1}{1+2n}},円_{1}F_{2}\left(n+{\frac {1}{2}};{\frac {1}{2}},n+{\frac {3}{2}};{\frac {-\pi ^{2}}{4}}\right)\end{aligned}}}

where 1 F 2 {\displaystyle ,円_{1}F_{2}} {\displaystyle ,円_{1}F_{2}} is a generalized hypergeometric function.

See also

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References

[edit ]
Discrete
univariate
with finite
support
with infinite
support
Continuous
univariate
supported on a
bounded interval
supported on a
semi-infinite
interval
supported
on the whole
real line
with support
whose type varies
Mixed
univariate
continuous-
discrete
Multivariate
(joint)
Directional
Degenerate
and singular
Degenerate
Dirac delta function
Singular
Cantor
Families

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