> > There are ICs called "digital down converters" from AD or Intersil... > Does anybody have ever tried to build an IQ-RX with those "guys"? > > Yes, the Analog Device AD6620 is one of them, and it is used in that > variety of SDRs that do A-to-D conversion directly > at RF, then digitally down convert the numeric stream to a more manageable > (for the PC) sampling rate. > The RFspace SDR-14 and SDR-IQ use that chip, as it does the newly > announced QS1R by Phil Covington
Alberto, thanks a lot for the details! I think I'll give it a try with an ADC that can do IF sampling up to 250MHz (for future projects). > > And does anybody know if there are ICs that can do FFT up to 60Msps? I > think ATMEL had one (must be 1 or 2 years ago). > > Do you really need to do an FFT at 60 Msps ? And what will you do then > with the frequency data ? That rate is way over > what a PC can handle. You will be forced to use a hardware-only > implementation... Well, you're right, depending on the FFT points it should be enough to have 8 - 10 Msps (which is still too much for SW). I was thinking about an RX that can do a wide-band FFT after a DDC. After that FFT I'd do some averaging to get down the sample rate and feed it to the PC for display. with the help of the DDC the bandwith could be adjusted to see more details and finally switch to demodulation. Maybe the VNAs from HP or Agilent do something like this as they have a much higher refresh rate than my old Anritsu VNA ;o) BR, Hannes. -- Der GMX SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! Ideal für Modem und ISDN: http://www.gmx.net/de/go/smartsurfer _______________________________________________ Winrad mailing list [email protected] http://winrad.org/mailman/listinfo/winrad_winrad.org
