Hi In my "through-the-air" tests with a couple of B210s the FFT filters presented much lower FER in comparison to the FIR filters at the Rx side. According to [1], the "FFT filters" downsamples after filtering while FIR downsamples before filtering.
cheers [1] http://www.trondeau.com/blog/2014/2/27/to-use-or-not-to-use-fft-filters.html On 15 December 2015 at 19:06, Saulo Queiroz <ssaulojo...@gmail.com> wrote: > Many thanks Bastian! > > I checked the loopback version and it seems to work very well. > > I'll check over-the-air and report here! > > On 15 December 2015 at 19:04, Bastian Bloessl <bloe...@ccs-labs.org> > wrote: > >> Hi, >> >> I replaced the Frequency Xlating FFT filters with FIR filters, used the >> Low-Pass Filter Taps block to generate taps (since I can’t get my head >> around this notation), and removed the filter from the first conversion. >> >> Now, it seems to work. At least it receives frames. If you still have >> problems I can send you the flow graph. >> >> Best, >> Bastian >> >> >> > On 15 Dec 2015, at 10:05, Saulo Queiroz <ssaulojo...@gmail.com> wrote: >> > >> > Each stream has been shiffted with the xlating block. >> > The intention is to "split" a 20 MHz wide analog channel into two of 10 >> MHz. >> > Each 10 MHz channel transmit its own ofdm frame. >> > I attached the flowgraph for more details. >> > >> > thanks in advance. >> > >> > On 15 December 2015 at 17:42, Martin Braun-2 [via GnuRadio] <[hidden >> email]> wrote: >> > tP indicates you're using corrupt tagged streams, maybe your add block >> > is overlaying them? I'm also not entirely sure what you mean by >> > 'simultaneous parallel transmissions'. Are they on different >> > frequencies? Are you mixing them together in baseband? >> > >> > Cheers, >> > Martin >> > >> > >> > On 15.12.2015 04:10, Saulo Queiroz wrote: >> > >> > > Hi all, >> > > >> > > I'm trying to Tx a same tagged stream simultaneously through two >> analog >> > > orthogonal channels. >> > > >> > > The flow path of each stream copy is: resampling, adjust tag lenght >> and >> > > xlating FFT filter (with shifting). After this I take the output of >> each >> > > filter and put into and add block then to the USRP sink. I also do the >> > > reverse process at the Rx side. >> > > With some packets are successfuly receive but with so many losses. At >> > > the Tx side I get many "tP". Any tip on how to set simultaneous >> parallel >> > > transmissions without this? >> > > >> > > I'm using gr-ieee80211 (thanks Bastian and team :) that has worked >> > > nicely with the single channel scenario. >> > > >> > > thanks in advance >> > > >> > > BR >> > > >> > > -- >> > > Saulo Jorge bq >> > > - "Beware of bugs in the above code; I have only proved it correct, >> not >> > > tried it." >> > > Donald Knuth. >> > > >> > > >> > > _______________________________________________ >> > > Discuss-gnuradio mailing list >> > > [hidden email] >> > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> > > >> > >> > >> > _______________________________________________ >> > Discuss-gnuradio mailing list >> > [hidden email] >> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> > >> > >> > If you reply to this email, your message will be added to the >> discussion below: >> > >> http://gnuradio.4.n7.nabble.com/Tag-preemption-USRP-sink-tp57286p57297.html >> > To start a new topic under GnuRadio, email [hidden email] >> > To unsubscribe from GnuRadio, click here. >> > NAML >> > >> > >> > >> > -- >> > Saulo Jorge bq >> > - "Beware of bugs in the above code; I have only proved it correct, not >> tried it." >> > Donald Knuth. >> > >> > wifi_tx_rx_loopback.grc (134K) Download Attachment >> > >> > View this message in context: Re: Tag preemption USRP sink >> > Sent from the GnuRadio mailing list archive at Nabble.com. >> > _______________________________________________ >> > Discuss-gnuradio mailing list >> > Discuss-gnuradio@gnu.org >> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> -- >> Dipl.-Inform. Bastian Bloessl >> Distributed Embedded Systems Group >> University of Paderborn, Germany >> http://www.ccs-labs.org/~bloessl/ >> >> > > > -- > Saulo Jorge bq > - "Beware of bugs in the above code; I have only proved it correct, not > tried it." > Donald Knuth. > -- Saulo Jorge bq - "Beware of bugs in the above code; I have only proved it correct, not tried it." Donald Knuth.
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