> On 30 Jan 2015, at 14:00, zs <zswx_...@126.com> wrote: > > Hi Bastian: > Thank you so much.I use the ofdm example,and I think maybe > the crc is wrong as you said,thank you. > Can you give me some advices to avoid these warning?Thank > you so much.
The fact that your CRC is not correct just means that *something* does not work. This can have a lot of reasons. For example you could try different gain settings. Also assert that the samples that you stream to your USRP are in the interval [-1, 1]. If that doesn’t solve your problem you can debug your flow graph with graphical sinks and check if the signal looks as expected. > > > > At 2015-01-30 00:43:12, "Bastian Bloessl" <bloe...@ccs-labs.org > > wrote: > >Hi, > > > >On 01/29/2015 03:13 PM, zs wrote: > >> Can you tell me,for general,in which circumstance,the packet header maybe > >> corrupt? > > > >This is very hard to tell since I don't know what you are doing. I guess > >you use a header_formatter in your flow graph and (for whatever reason) > >its header_parse method returns false. > > > >For example with the default header it looks like this happens if the > >CRC is not correct > > > >https://github.com/gnuradio/gnuradio/blob/master/gr-digital/lib/packet_header_default.cc#L132 > > > > > >> > >> > >> At 2015-01-29 20:44:13, "Bastian Bloessl" < > bloe...@ccs-labs.org > > wrote: > >>>Hi, > >>> > >>>On 01/29/2015 01:03 PM, zs wrote: > >>>> Detected an invalid packet at item INFO: Parser returned #f". > >>>> The answer may be "RF settings are distorting your signal" or others.I > >>>> want to ask a question.Which block in gnuradio give us this hint.Where > >>>> is the source code of the block?And have someone can help me to explain > >>>> this problem more details?Why will have this error/warning? > >>> > >>> > >>>~/src/gnuradio >> ack-grep -C 3 "an invalid packet" > >>>gr-digital/lib/packet_headerparser_b_impl.cc > >>>80- ); > >>>81- > >>>82- if (!d_header_formatter->header_parser(in, tags)) { > >>>83: GR_LOG_INFO(d_logger, boost::format("Detected an invalid packet > >>>at > >>>item %1%") % nitems_read(0)); > >>>84- message_port_pub(msg_port_id, pmt::PMT_F); > >>>85- } else { > >>>86- pmt::pmt_t dict(pmt::make_dict()); > >>> > >>> > >>>I guess your packet header is corrupt. > >>> > >>>Best, > >>>Bastian > > > > > -- Dipl.-Inform. Bastian Bloessl Distributed Embedded Systems Group University of Paderborn, Germany http://www.ccs-labs.org/~bloessl/ _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
