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Ronny Kunze Shinji.Ikari_de at gmx.deHello , that are really good news. How can i get such a upgrade board ? Best regards, Ronny Kunze Am 17.10.2012 18:55, schrieb Christian Daniel -- maintech GmbH: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hello everybody, > > since we found out that the Atmel SAM3U SSC interface is only capable > of transporting 500ksps worth of I/Q data, we heard a lot of > complaining because of the too narrow bandwith. Especially compared to > the rtl-sdr with about 2msps, our 500ksps was bit contrained. The > fact, that the OsmoSDR is much more sensitive to very small signals > and brings a 14bit ADC instead of 8bits did not really compensate for > the bandwidth loss. > > Also the mismatch between E4000 output resistance and ADC input > brought some unwanted spectral effects. > > Instead of just releasing stuff, we decided to fix both issues: I now > have a prototype with simple stack-on-board, that adds two op-amps to > decouple the E4000 from the ADC and lower the impedance and also this > board connecteds the available FPGA pins to the MCI (SD-Card) > interface of the Atmel SAM3U. > > For this to get working, we had to rewrite major parts of the ARM > firmware and the FPGA VHDL code. Today this work is completed and I > can report success: The OsmoSDR now delivers up to 4msps at 14bits. > Also the strange peaks around Niquist/zero frequency are gone. > > Find a screenshot of SDRangelove recording a DAB signal at 2msps > (SDRangelove needs some more love until it can cope with 4msps in > realtime - but we have verified that 4msps works without dropped > samples using the builtin FPGA test mode). > > http://www.cdaniel.de/download/osmosdr-dab-2mhz.png > > We will now integrate the changes into the OsmoSDR mainboard and > reroute the now free SSC pins to the pin headers instead of the MCI > interface. Also we will add the opamps. > > For the already produced OsmoSDR boards, we will have more of the > prototype stack-on-top-boards. > > We will keep you in the loop! > > Best regards, > Christian > > PS: Regarding the DAB screenshot: > - - The horizontal lines are correct - DAB uses a so called "pilot > symbol", which only has energy on a few carriers. That's why it looks > like a pause in the signal. > - - The vertical line is also correct - DAB does not use the middle > carrier to avoid I/Q offset problems on the transmitter side. > > - -- > - --------------------------------------------------- > | maintech # Dipl. Inf (FH) Christian Daniel | > | GmbH ### Otto-Hahn-Str. 15 · D-97204 Höchberg | > - --------------------------------------------------- > | AG Würzburg, HRB 8790 Tax-ID DE242279645 | > - --------------------------------------------------- > | http://www.maintech.de cd at maintech.de | > - --------------------------------------------------- > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.11 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ > > iQEcBAEBAgAGBQJQfuMIAAoJEHkgzUIsAWriHA0IAI2Agg0vnjLFa5dDpxu9AAkq > 6crr1Q/XAgrlmN8TY86yoYTMjJc7IZmjsAAGpidczZtSbwbmLFuTdQEo12dOvaZZ > GvkvNttoDE2zsnbU50MzWDK5BUcbfOJoQahX26P+8hbiaIsFKT8Gl8Ao9c2vz79u > e04Cl2SodmDDKnV84VL9i39+KZdkGcsbCWnFizqGzTbWyDkoSVviZORp20a3lCEZ > g8Af73jwDgVAU4lfrK9gO10G5jibHkQeULNIXFH8NbDiUPSF2557fGsu/9yC1UUC > msT0g41x8twb5nesT4ZtWDfQ3tUBgvLHn/ebv9xBxCX1Wg1W2FAFlcajbXx4zRQ= > =Taca > -----END PGP SIGNATURE----- >