>From Matlab MM documentation [1]: "[...] Typically, the input signal is the output of a receive filter that is matched to the transmitting pulse shape. [...]"
Assuming the MM Gnuradio implementation has the same hypothesis on the input signal (anybody can confirm this?), I deduced this block is usually misused when feed with a square signal, because it will take only one sample per symbol discarding the rest (with useful energy). You can put a Moving Average before for better results. This is one of the reason why the pfb_clock_recovery block is better, but unfortunately unfit for square signals [2]. I found even better results using a gaussian filter inside pfb_clock_recovery as the pseudo-matched filter to square pulses (with a proper bt value). (Obviously I can only guarantee this for the specific signal I worked with) [1] http://www.mathworks.com/help/comm/ref/muellermullertimingrecovery.html [2] See discussion: http://gnuradio.org/redmine/issues/812 2015-07-30 16:03 GMT-03:00 Iluta V <iluta2...@gmail.com>: > Hi, Tom, > > Could you be more specific where exactly it is not "the right algorithm"? > We'd appreciate that and would correct that in own work as well, if > Security Research Assessment made a mistake here. > > I will be looking forward to your response, > > Iluta > > > > On Thu, Jul 30, 2015 at 9:55 PM, Tom Rondeau <t...@trondeau.com> wrote: > >> On Thu, Jul 30, 2015 at 2:38 PM, Iluta V <iluta2...@gmail.com> wrote: >> >>> Research paper CONVERTING RADIO SIGNALS TO DATA PACKETS (Examination of >>> Using GNU Radio Companion for Security Research and Assessment) deals with >>> Clock Recovery MM, I attached the paper, have a look at: >>> >>> 6.Section 6.Counting the Bits >>> 7.Analyzing Demodulated Data >>> >>> Both deal with Clock Recovery MM usage and has flowgraphs. >>> >>> Best regards, >>> >>> Iluta >>> >> >> >> That's great, and I'm glad they got it to work for their application. >> Looks like they provide a good explanation of its use, too. Still, it's not >> the right algorithm. >> >> > > >> Tom >> >> >> >> >>> On Thu, Jul 30, 2015 at 9:23 PM, Tom Rondeau <t...@trondeau.com> wrote: >>> >>>> Another point to keep in mind is that the M&M block isn't great in >>>> fading environments. It's really suboptimal in general. Look at the >>>> pfb_clock_recovery block, instead. >>>> >>>> Tom >>>> >>>> >>>> On Thu, Jul 30, 2015 at 2:18 PM, Daniel Camara <danielcam...@gmail.com> >>>> wrote: >>>> >>>>> Hi Klauss, >>>>> >>>>> You could also take a look at >>>>> https://www.tablix.org/~avian/blog/archives/2015/03/notes_on_m_m_clock_recovery/, >>>>> it helped me quite a bit! >>>>> >>>>> Best regards... >>>>> >>>>> Daniel >>>>> >>>>> On Thu, Jul 30, 2015 at 7:17 PM, Martin Braun <martin.br...@ettus.com> >>>>> wrote: >>>>> >>>>>> Klaus, >>>>>> >>>>>> the manual page for this block has a paper reference in it: >>>>>> >>>>>> http://gnuradio.org/doc/doxygen/classgr_1_1digital_1_1clock__recovery__mm__ff.html#details >>>>>> >>>>>> M >>>>>> >>>>>> On 30.07.2015 10:16, Klauss Wolfeinstein wrote: >>>>>> > Hello, >>>>>> > >>>>>> > I would like to find a proper documentation on MM algorithm block >>>>>> (paper >>>>>> > for example). Any ideas ? >>>>>> > >>>>>> > Thank you. >>>>>> > >>>>>> > Regards. >>>>>> > >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> Discuss-gnuradio mailing list >>>>>> Discuss-gnuradio@gnu.org >>>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Best regards... >>>>> >>>>> Daniel >>>>> >>>>> _______________________________________________ >>>>> Discuss-gnuradio mailing list >>>>> Discuss-gnuradio@gnu.org >>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>> >>>>> >>>> >>>> _______________________________________________ >>>> Discuss-gnuradio mailing list >>>> Discuss-gnuradio@gnu.org >>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>> >>>> >>> >>> _______________________________________________ >>> Discuss-gnuradio mailing list >>> Discuss-gnuradio@gnu.org >>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> >>> >> > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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