Why we use raised root cosine or RRC filtering?

[bizoo]

i have a question about why we use raised root cosine or RRC filtring,

i am implementing BPSK, so if i have 1 i will send a cosine wave and if -1 i will send a 180 shifted cosine wave,

RRC is done to make signal less vulnerable to inter symbol interference, but what i am sending on the channel is cosine wave, i never used square pulses on the channel so why should i use RRC any way,
but the text seems to suggest to use RRC before sending any thing ont he channel

ne answers!

 

[amihomo]

raised root cosine

actually when you don't use RRC , you are using the rectangular pulse shaping by default.
when using the RRC , the pulse shape is not rectangular ,and each symbol period is filtered with the RRC filter , then the resulting pulse shape is applied to the sin & cosine waves .

regards

 

[bizoo]

Re: raised root cosine

HMM the last part You said taht pulse has a RRC shape and then this shape is applied on sine and cosine waves, i can visualize that


Can You please provide me some image of that some where, any website? any links,
i just want to see the difference in waveforms send on the channel when using a square pulse and compare it with RRC generated waves

 

[amihomo]

Re: raised root cosine

check this out

Inter Symbol Interference (ISI) and Raised cosine filtering
**broken link removed**

hope this helps you