Do you actually have any evidence or plots showing excess jitter in the HackRF One and its effect on gr-dvbt demodulation, or are you just making it up?
It sounds like you have come to a conclusion without understanding the problem. --n On Thu, Jul 6, 2017, 7:15 AM Stack Programer <stackprogra...@gmail.com> wrote: > Yet i work on DVB-T in HackRF one, in TX we can send DVB-T and we receive > it with a hardware dongle DVB-T. but for receiving with SDR Based we had > error: see this link for our older > <http://blog.stackprogramer.xyz/en/2017/02/18/dvbt-project-receiver-probelm-oorestart-aquisition-d_freq_offset-5-od_freq_offset-5/> > work or this > <https://www.maximintegrated.com/en/app-notes/index.mvp/id/1916> link. > > DVBT project receiver probelm OOrestart aquisition d_freq_offset: -5 > Od_freq_offset: -5 > > So for examine my problem i created a new issue on hackrfone github > project see this <https://github.com/mossmann/hackrf/issues/390> link, > every thing i found i will update there. In older our post we define jitter > error , for more info you can see this > <http://blog.stackprogramer.xyz/en/2017/06/18/definition-of-some-of-important-elements-of-digital-communication/> > link. > > Fig1:Jitter error diagram description > > - *So we start examine that how we observed HackRF One has Random > jitter errors??* > > my reason why HackRF One has random jitter error, In protocol like gr-dvbt > <https://github.com/BogdanDIA/gr-dvbt>,gr-ofdm,gr-atsc that they are ofdm > based modulation, we had not any response in receiver mode in dvb-t we had > famous error: but frequency offset instantly from -5,3,2,7,…. > > restart aquisition d_freq_offset: -5 Od_freq_offset: -5 > > So we had a error in uncertianly frequency and other hand it is random, > so we had radom jitter errror.for more info see this > <http://www.eetimes.com/document.asp?doc_id=1204338> link. > > - *reason of causing HackRF One has Jitter error?* > - Low Resolution ADC: > > after some search i concluded that one of reason for random jitter error > in HackRFOne is low resolution ADC, it has 8 bit ADC,please see this > <https://www.maximintegrated.com/en/app-notes/index.mvp/id/4466> link > that describe how low resolution ADC can create jitter errors . > > - Low SNR in HackRF One: > > For problem long switch diode stage in RF HackRF One it is more noisy vs > USRP. So it use long way RF, it should edited in newer version. > > you can see in below image and link that how bad SNR and low ADC > resolution can caused jitter errros. > > for more info please see this > <https://www.maximintegrated.com/en/app-notes/index.mvp/id/4466> link. > > > > [image: jitterADC] > > Fig2:low resolution ADC can cause jitter errors > > > > So we saw that HackRF One in OFDM based modulation and high carrier or in > high bandwidth it sucks and it has random jitter errors, so we should ask > myself that we need new design opensource hardware SDR hardware? > > But some question is need to answered?? > > *why is mention HackRFOne has bandwidth 20 MSPS…..*?? > we should define bandwidth and sps in high carrier modulation > it has problem in high carrier modulation?.So really HackRF One have > Bandwidth more than 2 MSPS? > > *but what's solution?* > > - > using a external clock for hackrf one??? > - > design a new hardware………? > > i liked hackrfone for reason that is opensource and hardware, but with > this condition i concluded that > we should think a new way for future sdr hardware opensource? > > best regards stackprogramer > > Fig3:HackRFOne a opensource hardware SDR hardware > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
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