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Re: [Discuss-gnuradio] 8b/10b for GMSK
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] 8b/10b for GMSK |
Date: |
Sun, 4 Feb 2007 11:27:36 -0800 |
User-agent: |
Mutt/1.5.9i |
On Sun, Feb 04, 2007 at 02:32:30AM -0800, Brett Trotter wrote:
>
> After coming up with some scripts to generate thousands of 200-byte random
> files and attempt to transfer them over a GMSK link, I isolated 5 of 10,000
> 'files' that cause the packet to be dropped (when the MTU is big enough to
> hold the entire 200 bytes- which should be all the time)- most likely due to
> repeated zeros or ones that cause a loss of sync. Upon debugging the output
> after the whitener, it does appear that there are instances of around
> 12-zeros in the packets that don't work.
What's the maximum run length that you see in packets that _do_ work?
My understanding from talking to Johnathan is that he has some
packets that work that have 17-bit runs in them (post-whitener).
(Not sure if they're ones or zeros.)
This makes me think that the 8b/10b "solution" is premature, given
that the problematic symptom is not yet nailed-down.
In summary, create the smallest test case you can that reproduces the
problem. When you've got that under control, figure out the next
step.
I suspect that some adjusting of control loop constants may be in order.
Eric
- [Discuss-gnuradio] 8b/10b for GMSK, Brett Trotter, 2007/02/04
- Re: [Discuss-gnuradio] 8b/10b for GMSK,
Eric Blossom <=
- Re: [Discuss-gnuradio] 8b/10b for GMSK, Johnathan Corgan, 2007/02/04
- Re: [Discuss-gnuradio] 8b/10b for GMSK, Johnathan Corgan, 2007/02/05
- Re: [Discuss-gnuradio] 8b/10b for GMSK, Brett L. Trotter, 2007/02/05
- Re: [Discuss-gnuradio] 8b/10b for GMSK, Johnathan Corgan, 2007/02/05
- Re: [Discuss-gnuradio] 8b/10b for GMSK, Brett L. Trotter, 2007/02/05
- Re: [Discuss-gnuradio] 8b/10b for GMSK, Johnathan Corgan, 2007/02/05