FLL = Frequency lock looping. The corresponding C++ block is digital_fll_band_edge_cc. and you can find the usage example in generic_mod_demod.py in /gnuradio/gr-digtial/python. There are some discussions within this community before, just search it for how to use it properly.
On Wed, May 29, 2013 at 10:07 PM, yeran <[email protected]> wrote: > Hi Alex, > > Thank you for your prompt reply! > > But I don't quite understand what you said about FLL filter for CFO > correction. What is the full name of the FLL filter? In which block? > > Thanks! Look forward to your reply! > > Ada > > ------------------------------ > Date: Wed, 29 May 2013 21:55:29 -0500 > Subject: Re: [Discuss-gnuradio] channel estimation in gnuradio narrowband > From: [email protected] > To: [email protected] > CC: [email protected] > > > I don't think the RRC filter is used for carrier frequency correction. In > gnuradio, the FLL filter can be used for CFO correction. > Please correct me if I am wrong. > > > On Wed, May 29, 2013 at 9:43 PM, yeran <[email protected]> wrote: > > Hi everyone,**** > > > I’m doing channel estimation in gnu radio narrowband. But the result is > different than I expect.**** > > > I’m using the example in grc, uhd_tx_dpsk.grc and uhd_rx_dpsk.grc. Send > vector (255,255,255) repeatedly using BPSK. At the receiver, I add a file > sink after the time_recov block and store the data.**** > > > Y=X*H +N, the data after time_recov is Y, and in BPSK, when sending 1 is > mapped to 1+0j, so X=1+0j. Thus, Y/X is the estimate channel frequency I > get. I plot the absolute value of the channel frequency and get a figure as > in the attachment. But it seems that it has the carrier frequency with it. > It is so well organized and changes regularly. But I’m pretty sure that > before the file sink, in the time_recov block, the rrc filter already take > off the carrier frequency.**** > > > Has anyone come across the same problem before? Or find any mistakes or > suggestions on my method? Please let me know!**** > > > Thank you very much!**** > > Ada > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > -- > > Alex, > *Dreams can come true – just believe.* > -- Alex, *Dreams can come true – just believe.*
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