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