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Annual Report 2000 - WIT

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¾<br />

°<br />

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<br />

$<br />

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$<br />

È<br />

ÄÉ<br />

Æ<br />

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ý<br />

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ý<br />

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À<br />

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È<br />

¨#É<br />

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ý<br />

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R<br />

À<br />

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g<br />

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È<br />

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¨<br />

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¿<br />

¿<br />

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g . The minimization of ª ¾ Í“Î <br />

$<br />

¿<br />

R<br />

–<br />

<br />

<br />

<br />

À<br />

<br />

¾<br />

°<br />

265<br />

have the same importance as that of the primary field has along the trace (see Figure 1<br />

and 2).<br />

The WHL filter governing equations is a<br />

¾ —–<br />

natural stationary model, and the filter<br />

is the unknown time-invariant operator that is constrained —–<br />

to satisfy a desired output<br />

through the commonly referred to as the Wiener-Hopf ¿ integral equation. We<br />

continue with the equations in the convenient canonic forms, with a uniform discretization<br />

as already established in the Goupillaud model. The criteria<br />

<br />

for<br />

g<br />

the<br />

<br />

filter<br />

g<br />

is<br />

<br />

the<br />

g g<br />

minimization of the variance error, (desired signal)<br />

ç<br />

(real output) in time domain:<br />

<br />

and À<br />

g<br />

, between ¿<br />

ýÁÀ<br />

¯ÇÆ<br />

Ä Å<br />

ª ¾<br />

g<br />

g<br />

è (5)<br />

± ùœÊ Ë Ì<br />

¥ÃÂ<br />

The filter real output is simply:<br />

results in the general WHL equation:<br />

g<br />

¾ g<br />

¾ g<br />

QÐ<br />

QÐ<br />

è (6)<br />

¢3ÏqÏ<br />

ýÑ¢ÒšÏ<br />

The solution defines the coefficients g which depends on what kind of operation<br />

is to be intended for, and accomplished by a priori conditions.<br />

¾ è represents the<br />

theoretical autocorrelation of the input, and<br />

¢:ÏqÏ<br />

è is the theoretical stochastic unilat-<br />

¢ÒšÏ<br />

eral crosscorrelation between the desired and the observed signals. The filter quality<br />

is here also measured by the formula of the normalized minimum error given by the<br />

summation:<br />

è (7)<br />

ªXÓ<br />

Þ<br />

g<br />

¾ g<br />

š§<br />

ý©´<br />

¢ÒšÏ<br />

¤ ¢3ÏqÏ<br />

6 -<br />

The KBC filter governing equations in a natural non-stationary model, and the data<br />

window does not satisfy the principles underlined by the convolution integral. For this<br />

reason, the equation is rewritten in the form of a moving average according to the<br />

commonly referred to as the Wiener-Kolmolgorov problem, and it is expressed by the<br />

matrix integral equation:<br />

Ô–<br />

Ô–<br />

Ô–<br />

—–<br />

—–<br />

¢ ÒšÏ<br />

ý×Ö<br />

¢ ÏqÏ<br />

ý’Ö<br />

q Ú<br />

ÚÛ<br />

(8)<br />

,¿<br />

a¿<br />

#Õ<br />

bÚ<br />

Ú€#Õ<br />

Ú€<br />

Ú€#Õ<br />

bÚ<br />

Ô–<br />

Ô–<br />

where is the actual output, and ¾ is the corresponding desired optimum<br />

À<br />

time-variant operator. The criterion used is the minimization of the residue covariance<br />

° bÚ<br />

expressed as:<br />

è (9)<br />

ÙØ<br />

ÙØ<br />

ª ¾<br />

—–<br />

Ô–<br />

jß<br />

¥ÝÜQÞ À<br />

ùaà

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