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Capitolul 1: Bancuri de filtre

Capitolul 1: Bancuri de filtre

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Demonstraţie (1)<br />

• Relaţie elementară între rădăcinile <strong>de</strong> ordinul M ale unităţii<br />

M−1<br />

∑<br />

l=0<br />

w −ln<br />

M<br />

M−1<br />

= ∑<br />

l=0<br />

e j2πln/M =<br />

{<br />

M, dacă n mod M = 0<br />

0, altfel<br />

(2)<br />

• Dacă n mod M = 0, atunci toţi termenii din sumă sunt 1<br />

• Altfel<br />

M−1<br />

∑<br />

l=0<br />

e j2πln/M = 1 − ej2πn<br />

1 − e j2πn/M = 0 PAS cap. 1: <strong>Bancuri</strong> <strong>de</strong> <strong>filtre</strong> – p. 5/75

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