Re: [Discuss-gnuradio] Observing Random Jitter in HackRF One in High Bandwidth with High Carrier Modulation

[Cinaed Simson]

Post the gnuradio flowgraph you used.

If you have a complaint with the HackRF hardware, post the complain on
the HackRF mailing list

  https://pairlist9.pair.net/mailman/listinfo/hackrf-dev

And if you're only getting 2 MSPS with the HackRF on your computer then
you just have a slow computer - or it's operator error.

See

  https://greatscottgadgets.com/sdr/

for a tutorial on the HackRF.

-- Cinaed

On 07/06/2017 07:14 AM, Stack Programer 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 seethis
> <https://www.maximintegrated.com/en/app-notes/index.mvp/id/4466> link.
> 
>  
> 
> 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
> 
>  
> 
> 
> 
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