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Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using
From: |
Martin Braun |
Subject: |
Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location) |
Date: |
Wed, 22 Jan 2014 10:15:10 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 |
On 01/21/2014 07:16 PM, Aditya Dhananjay wrote:
> On Tue, Jan 21, 2014 at 1:03 PM, David Halls
> <address@hidden <mailto:address@hidden>> wrote:
>
> Ah, I see. You want to isolate the effect of the channel. I believe
> it will be difficult, if not impossible, to remove the slight jitter
> of the trigger, even in very high SNR - perhaps others can comment/help?
>
>
> Yes, that is correct. It is impossible to *eliminate* the jitter in
> triggers from Schmidl-Cox. But I want to minimize it, and have edited
> the plaueau/peak detector code to do just that. (all in a hackish manner!)
Hm, this will be hard to get right. After all, the Schmidl & Cox is an
estimator and operates on noisy values. Unless your SNR is crazy good,
there is always a chance of getting it wrong. And technically, even then.
Two ideas:
- You could remove the sync block and sync your rx/tx paths with other
means (e.g. MIMO connector, it depends on your hardware). This makes the
sync influence independent of the noise.
- Reconsider if the phase rotation really makes your measurements
invalid. You'll have a phase rotation in any case (due to channel,
propagation time etc.). The timing-related phase offset is constant,
after all, and the phase difference between sub-carriers depends on the
sub-carrier distance, too. Perhaps it doesn't matter all that much?
MB
- [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), David Halls, 2014/01/21
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), Aditya Dhananjay, 2014/01/21
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), Martin Braun, 2014/01/21
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), Aditya Dhananjay, 2014/01/21
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), David Halls, 2014/01/21
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), David Halls, 2014/01/21
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), Aditya Dhananjay, 2014/01/21
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), David Halls, 2014/01/21
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), David Halls, 2014/01/21
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), Aditya Dhananjay, 2014/01/21
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location),
Martin Braun <=
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), Aditya Dhananjay, 2014/01/22
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), David Halls, 2014/01/23
- Re: [Discuss-gnuradio] header_payload_demux_impl.cc - problem when using random bit stream (variable trigger location), Martin Braun, 2014/01/28