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

What actually is the advantage of upsampling ?

Status
Not open for further replies.
Z

zeerum

Junior Member level 3
Joined
Nov 26, 2006
Messages
27
Helped
2
Reputation
4
Reaction score
1
Trophy points
1,283
Activity points
1,481
matlab question

hi
we were given a code about simulation of bpsk. in that code signal was upsampled. and then during pulse shaping by root raised cosine filter, it was multiplied by squareroot of upsampling factor as follows


x=round(rand(1,16000)); %generating random data
xk=(-1).^x; %generating BPSK symbols

x_input=upsample(xk,100);
b=sqrt(100)*firrcos(255,0.01,1,2,'rolloff','sqrt');



i want to know what actually is the advantage of upsampling( inserting extra zeroes between samples) and why was firrcos multiplied by sqrt(100)?

please explain on basic level as i am beginner to all of this.
thx
 

matlab question

Hi,

1- Pulse shaping filter reduce side lob level and interference to other channel frequencies, but we have two choice for implementing Raise Cosine filter, (a) using analog filter after D/C converter, or (b) using upsampling for practical possibility of digital implementation.

2- sqrt(100) is because after upsampling signal power decrease 100 times and for canceling this effect we should multiple output by sqrt(100).

Regards
 

    Z

    zeerum

    Points: 2
    Helpful Answer Positive Rating
Re: matlab question

thnx mahdithdn
that was great help
see these are conceptual querries which hardly get answered during lectures
so can u refer any book or material that would help me?
 

matlab question

Hi zeerum

about upsampling you can refer to Discrete-Time Signal Processing by Allen Oppenheim. but I'm not able to suggest any book about discrete implementation of digital modulation, maybe the best advise is using Matlab communication toolbox and studying well-known book Digital Communication by Praokis (or a simpler book by Haykin).

Regards
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top