osmo-fl2k baseband to carrier

historical

Hi Jean-Paul,

no, as the warning in the GRC console should have told you: 
NEVER use a throttle in a hardware flow graph. It doesn't do anything,
but will lead to continuity problems.

You can't define a signal at 35 MHz with a 35 MHz real-valued sampling
rate – you'd need twice of that, at least; but since your sampling rate
also defines the distance between spectral images, more careful choice
of sampling rate is necessary for succesfull undersampling.

Best regards,
Marcus

On Wed, 2018-05-02 at 19:10 +0000, azerty lr wrote:
> Hello,
> 
> Ok so the Gnu Radio diagram that I did is correct? I tried a carrier
> frequency of 1 Mhz with a sampling rate of 31 Mhz of I should have
> got a signal at 30Mhz but it was not working very well. I needed a
> carrier of at least 2 Mhz to got a signal.
> 
> Best regards,
> Jean-Paul
> De : Müller, Marcus (CEL) <mueller at kit.edu>
> Envoyé : mercredi 2 mai 2018 12:42
> À : azerty_lr at hotmail.com; osmocom-sdr at lists.osmocom.org
> Objet : Re: osmo-fl2k baseband to carrier
>  
> Well, as a VGA adapter, the FL2000 doesn't come with any mixer.
> So, all you can do is use images, since the DAC also lacks a proper
> reconstruction filter. You get mathematical repetitions at every
> multiple of the sampling rate – "undersampling" is the the term you
> want to read up on.
> 
> Best regards,
> Marcus
> 
> On Tue, 2018-05-01 at 12:03 +0000, azerty lr wrote:
> > Hello,
> > 
> > First thank you for this FL2000 hack, it's very nice!
> > 
> > I tried to make an FM & AM transmitter with it and GNU Radio. It's
> working fine if I save to a file and then use fl2k_file to transmit
> the data but with the tcp server and fl2k_tcp, my computer is not
> fast enough to sample in real time at 100 MHz. I also tried with a 35
> Mhz sampling rate but it's not real time. Here is the diagram I used.
> > 
> > Is there a possibility to avoid sampling at a very fast rate if the
> data bandwidth is small to do the baseband to carrier shift?
> > 
> > 
> > Thank you,
> > Best regards,
> > Jean-Paul