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Techniques à étalement de spectre - IUT

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DSSS –<br />

Direct Sequence Spread Spectrum<br />

Technique la plus répandue aujourd’hui : 802.11b<br />

14 canaux <strong>de</strong> 20 MHz<br />

Fréquences crête espacées <strong>de</strong> 5 MHz<br />

canal 1 = 2,412 GHz ; canal 14 = 2,477 GHz<br />

Canal1 Canal7<br />

Canal13<br />

2,4 GHz 2,4835 GHz<br />

Largeur totale <strong>de</strong> la ban<strong>de</strong> = 83,5 MHz<br />

Canaux recouvrants : inexploitables simultanément<br />

simultan ment<br />

Fréquence

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