Re: [Discuss-gnuradio] PSK Mod Block

[Nowlan, Sean]

Introducing ISI to a PSK signal with a root-raised cosine (RRC) filter is a standard communications technique. At the receiver, use a matched RRC filter to eliminate the intentional ISI introduced at the transmitter. This works because the combined filter response of the two filters is a raised cosine pulse, which satisfies the Nyquist criterion for zero ISI.

 

In the PSK Mod block, the filter construction is not exposed to the user except through the excess bandwidth or roll-off parameter. You could adjust that bandwidth factor to be close to zero, but this will create a very long filter. If you really want to do what you are saying, it would be worth looking at the source code for the PSK Mod block, and taking the filter out. However, it is likely that you don’t really want to do this.

 

Sean

 

From: discuss-gnuradio-bounces+address@hidden [mailto:discuss-gnuradio-bounces+address@hidden On Behalf Of Surya Agam
Sent: Tuesday, June 23, 2015 9:47 AM
To: GNURadio Discussion List
Subject: [Discuss-gnuradio] PSK Mod Block

 

Hello,

 

I wanna use PSK Mod Block, but the ISI is annoying. Why PSK Mod Block have a it's own ISI?

And also is there anyway to disable the ISI from the block?

 

--

Sincerely,

 

Surya Agam

University Al Azhar of Indonesia, Jakarta