Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

How despreading in DSSS is achieved?

Status
Not open for further replies.
F

fanshuo

Full Member level 5
Full Member level 5
Joined
Jun 21, 2007
Messages
266
Helped
8
Reputation
16
Reaction score
4
Trophy points
1,298
Location
Netherlands
Activity points
2,746
hi all,
I am not very familiar with DSSS.
I want to know how despreading is achieved? by simply multiplication with the corresponding PN ? or It depends on how the signal is spreaded?

Because I found that the spreading in 802.15.4 is achieved by mapping not multplication. I do no know how despreading will be achieved?

thanks!
 

how to despread?

Speading will be acheived by multiplying a key c(t) ,which behave such a psudo noise, to your original signal s(t). c(t) is consists of -1 and 1. so at the receiver side when you multiply the received signal by c(t), you will have c(t)^2 s(t). the first term is always 1.
Zigbee (IEEE802.15.4) use BPSK as its modulation. in this case the transmitted signal is c(t) or -c(t). so in receiver you only need to discover if it is c(t) or -c(t) (e.g. by considering the first bit only). Is it clear?
 
  • Like
Reactions: acp27

    A

    acp27

    Points: 2
    Helpful Answer Positive Rating
Re: how to despread?

Please Read this book you can download it from TLFebook website

Springer.Principles.of.Spread.Spectrum.Communication.Systems.eBook-TLFeBOOK
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top