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Spreading Codes:
di(t)+1+1+1+1-1-1-1-1+1+1+1+1
ci(t)-1+1+1-1-1-1+1-1+1+1-1-1
di(t) · ci(t)-1+1+1-1+1+1-1+1+1+1-1-1
di(t) · ci(t)-1+1+1-1+1+1-1+1+1+1-1-1
ci(t)-1+1+1-1-1-1+1-1+1+1-1-1
di(t) · ci(t) · ci(t)=di(t)+1+1+1+1-1-1-1-1+1+1+1+1


In order to spread the data sequence (Direct Sequence Spread Spectrum), the code sequence must be:
  • Much faster than the data sequence.
  • Exhibit some Randomness properties.
Note that the data sequence has a slower speed (less transitions) than the Code sequence. By Multiplying the data sequence with the faster code sequence, the resulting product yields a sequence with more transitions than the original data. (Faster speed). With suitable random-like codes the resulting sequence will have the same speed as the code sequence.


CODE: AN INTRODUCTION
By Dr. Ernest Simo
© 1999 DR. ERNEST SIMO - SPACE2000
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