beautypg.com

Direct sequence spread spectrum, Signal spectrum – Siemens IEEE802.11 User Manual

Page 21

background image

,

© Siemens, 2002

11 chips

1 bit period

11 chips

1 bit

period

Data

PRN

Out

11 Bit Barker Code (PRN*)

0100100011110110111000

Transmitter baseband signal after spreading

Transmitter baseband signal before spreading

Receiver baseband signal after matched filter (De-spread)

Receiver baseband signal before matched filter (Correlator)

RF Energy is Spread by XOR of Data with PRN Sequence

Signal

Spectrum

1

0

1011011100010110111000

* PRN: Pseudorandom Number

Direct Sequence Spread Spectrum