Friday, 14 February 2014

Crazyscan2 and TBS 6280






I finally managed to track down a TBS 6280 PCI card that I could use for testing
DATV-Express. A TBS 6220 card would have worked just as well. So above is
a constellation display of DATV-Express transmitting 64QAM with 7 MHz
channel spacing and 2k FFT. It seems that while it does work just with the FPGA
producing the clock it works a lot better with an Si570 fitted. The program I am
using to do the display is crazyscan2.

4 comments:

  1. My memory is not good, but isn't the oscillator 100ppm? Maybe a better crystal oscillator?

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  2. It is the clock generation for the DAC that causes the noise,
    the FPGA approximates the sample rate. It is perfectly
    adequate for DVB-S. We never set out to do DVB-T, the fact
    the boards can do it is a bonus.

    ReplyDelete
  3. Is this blog dead now?

    ReplyDelete
  4. No it is not, however I only blog when I have something I think people will be interested in. Currently I am very busy learning how to program the latest generation of SOC devices from Altera so I have not had much time for other radio related things.
    I am also on Twitter @G4GUO if people can't get enough from here :)

    ReplyDelete