Continuous time Gaussian process

rsingh628

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May 31, 2021
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Hello. This may not be the right place to post, so apologies.
I am stuck on how to begin with the following problem on continuous time Gaussian processes. How do approach the integrals? I do know that W(t) has a constant PSD which would mean the autocorrelation function is a delta function. In the frequency domain, g(t) and h(t) would become sinc functions.

1670714559747.png
 
An initial attempt I've done (although mostly likely wrong)

Since the PSD is constant, I believe W(t)W(t) is simply a delta function δ(t)\delta (t) by taking the inverse Fourier transform of 1.

X=01g(t)W(t)dt X=\displaystyle\int_0^1 g(t)W(t)dt = 01g(t)δ(t)dt \displaystyle\int_0^1 g(t)\delta (t)dt = g(0)=1g(0) = 1 (hopefully I can use the sifting property of the delta function)

Y=01h(t)W(t)dt+12h(t)W(t)dt Y=\displaystyle\int_0^1 h(t)W(t)dt + \displaystyle\int_1^2 h(t)W(t)dt = 01h(t)δ(t)dt+12h(t)δ(t)dt=1+1=2 \displaystyle\int_0^1 h(t)\delta (t)dt + \displaystyle\int_1^2 h(t)\delta (t)dt = 1+1=2

So, to calculate the correlation coefficient I would use the formula below, but now I need the variances. Do I use Var(X)=E(X2)(E(X))2 Var(X) = E(X^2) - (E(X))^2 ?

An initial attempt I've done (although mostly likely wrong)

Since the PSD is constant, I believe W(t)W(t) is simply a delta function δ(t)\delta (t) by taking the inverse Fourier transform of 1.

X=01g(t)W(t)dt X=\displaystyle\int_0^1 g(t)W(t)dt = 01g(t)δ(t)dt \displaystyle\int_0^1 g(t)\delta (t)dt = g(0)=1g(0) = 1 (hopefully I can use the sifting property of the delta function)

Y=01h(t)W(t)dt+12h(t)W(t)dt Y=\displaystyle\int_0^1 h(t)W(t)dt + \displaystyle\int_1^2 h(t)W(t)dt = 01h(t)δ(t)dt+12h(t)δ(t)dt=1+1=2 \displaystyle\int_0^1 h(t)\delta (t)dt + \displaystyle\int_1^2 h(t)\delta (t)dt = 1+1=2

So, to calculate the correlation coefficient I would use the formula below, but now I need the variances. Do I use Var(X)=E(X2)(E(X))2 Var(X) = E(X^2) - (E(X))^2 ?

18E93BD7-9E28-4637-BE35-B31E99C09882.png
 
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