Re: [Discuss-gnuradio] Questions about OOK mod and demod

[Brian Padalino]

On Wed, Jul 18, 2012 at 2:49 PM, lliao003 <address@hidden> wrote:
>
> Hi all!
>
> I am a rookie and I am working about OOK mod and demod. I have few questions
> following:
>
> I modify the digital_constellation.cc file as
>
> d_constellation[0]=gr_complex(0,0)
> d_constellation[0]=gr_complex(1,0)
>
> like this, I think after re-make, I already achieve OOK mod. However, in
> order to build ook demod, I modify as following:
>
> return (real(*sample)>0.5)

You really want that to be the magnitude of the sample, not just the
real portion.  If you wanted to avoid the sqrt, magnitude squared can
probably work as well.

> I also embed OOK mod and demod into GRC and try to simulation in GRC whose
> flow graph is
> File Source->packet Encoder->OOk mod->Channel Model->Throttle->OOk
> demod->Packet decoder->File sink.
> If there is no noise in channel model, ook mod and demod work perfect, but
> if there is any noise, I can not receive any file.
>
> Anyone can tell me if I did wrong in modifying the code or there are still
> something I need to modify. Thank you for time and help very much!

Are you filtering your demodulated OOK signal afterwards?  Beforehand?
 How many samples/symbol are you running?

So many questions!  Good luck!

Brian