discuss-gnuradio
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] ATSC fixups


From: Andrew Davis
Subject: Re: [Discuss-gnuradio] ATSC fixups
Date: Mon, 15 Jul 2013 22:01:33 -0400

Sure:

- first the description is correct and not just copied from interp_short.py
- removed the writing to 'atsc_complex.data' as this uses a lot of space and seems to have no meaning outside of debugging
- I use interleave_short_to_complex instead of s2s -> s2f -> f2c chain
- lp_coeffs and duc_coeffs uses input_rate instead of just the number, should make changing it easier
- lp_coeffs no longer arbitrarily adds 3 gain
- duc now shifts the frequency in the correct direction
- the root raised cosine filter taps no longer need to be heterodyned into place as I just use it at baseband
- the root raised cosine filer gets used now ( for some reason it was not in the chain before and this was severely causing ISI )
lower_edge and upper_edge seemed arbitrary and were not in the right spot anyway

After this stuff and the reorganization a simple diff would not have saved much, 
also i'm working on 'atsc_tx.py',so 'all_atsc.py' would be confusing, hence the name change.

Also the other scripts seem unnecessary with the new thread-per-block sceduler, the also seem to cause
a lot of beginners confusion. So I felt they needed to go.

I have also built a ( semi ) working complex fpll for gr-atsc, this removes the need for up-converting and the filtering
after the current fpll, my next atsc_rx will need the new script style. After I finish updating the bit timing loop 
we will be almost real time I believe!

P.S. I could still just do the diff to the old all_atsc.py and rename if you want.

Thank you
Andrew


On Mon, Jul 15, 2013 at 6:52 PM, Johnathan Corgan <address@hidden> wrote:
On Sun, Jul 14, 2013 at 12:03 PM, Andrew Davis <address@hidden> wrote:
 
I have been working on getting gr-atsc running again, I have found a few speedups and some bugs that prevented ATSC decoding from working with new versions of GNURadio. I have put these fixes into a branch that can now decode signals from my local TV station. The changes are in commit in this branch: https://github.com/glneo/gnuradio/tree/atscfixup

Andrew, can you detail the difference in implementation between the atsc_rx.py file you added and the all_atsc.py file that was there already?

--
Johnathan Corgan
Corgan Labs - SDR Training and Development Services
http://corganlabs.com


reply via email to

[Prev in Thread] Current Thread [Next in Thread]