Spread spectrum

[bob]

Hello

I was wondering if convolutional codes are considered spread spectrum in a similar manner to CCK in 802.11b. Traditional Direct Sequence Spread Spectrum like modulating a bit stream with a pseudo-random (higher rate) sequence or modulation of a bit with a Walsh or Barker code are clearly spread spectrum as there are many chips/bit. CCK in 802.11b still looks like 8 bits in 8 bits out, but is called spread spectrum. As such would a convolutional code be considered spread spectrum?

Thanks
Bob

[charan langton]

Hello Bob,

The convolutional codes do spread the signal but thats all the similarity there is between spread spectrum and convolutional codes. In spread spectrum various signals occupy the same frequency separated by the orthogonality of the code used. There is no condition for orthogonality with convo codes. So my final word would be that the convolutional codes can not be considered a form of spread spectrum.

Charan