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From: | Julius Durst |
Subject: | Re: [Discuss-gnuradio] Reconnecting OFDM rx |
Date: | Tue, 21 Jul 2015 16:15:33 +0200 |
Hi,I had a peek inside the S&C block, it's a hier block, so I simply rebuilt it with the single blocks it composed of. Aaaaand it works. But I did not see anything wrong in the hier block. Maybe it could be because of buffers, which get flushed or some do and some do not or something like that? Could it be a bug?
So that was the "solution" for the first problem. Now for the second one: After reconnecting, every detection lead to the
INFO: Detected an invalid packet at item 192 INFO: Parser returned #f INFO: Detected an invalid packet at item 240 INFO: Parser returned #f ... and so onerror. I figured out that this is a problem of the header/payload demux, which is stateful. Because it got no new items/samples when disconnected, after reconnection it took the new items as part of the old paket, so all in all the wrong header for the wrong payload. I solved this by feeding the rx with a null source while it is disconnected. I'm still not sure if this could avoided and if it makes sense if the HPDemux looked for a new trigger, even if the old paket was not complete. But for now I won't go deeper into this block.
So to make it easier than rebuilding the S&C block from its single components, is it possible to let gnuradio clear all buffers, even the ones inside a hier block?
Or any other ideas what could be the problem with the S&C block?For anyone interrested or if you want to try the difference between S&C and "self made" S&C: http://pastebin.com/r88MKGEv
BR Julius On 14.07.2015 19:17, Martin Braun wrote:
On 14.07.2015 10:03, Julius Durst wrote:Hi Martin, I don't exactly understand what you mean. I connected the Tag Debug to both outputs of Schmidl&Cox, but that does not seem to add any tags even when running in the "normal" mode. I don't think it is supposed to as it doesn't get any keys. When disconnecting the rx, the detect output of S&C stops (no new samples come out of it). When reconnecting the rx, I get a flow of zeros from the detect output (no more detections). This is where I'm really wondering if it is doing what it is supposed to.Yeah, I meant 1s on the detect output, not tags. But I see you got what I meant. And this is what I meant; the S&C is pretty robust and doesn't care about states (it does have some memory, though, for the averaging). It shouldn't care less if something was disconnected or not. Anyway, if only zeros are coming from the detect output, that's the issue right there. Can you have a peek inside that block, see what's going on? Cheers, Martin
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