<snip> When you set up these units for the first time, select 0 for the RCF output shift parameter. The AD6620 chip inside the SDR-14 or SDR-IQ produces 24 bits of data but the USB link can only transfer 16 of them to the PC. By setting the RCF output shift to zero you will use the lowest bits and this way you assure that the internal noise floor of the unit is truly represented on the digital side. <snip> Is this true for all USB links from receiver to PC or just SDR-XX ... Jim KI6MZ
Leif Asbrink wrote: > Hi Vojtech, > > >> I built a SoftRock RXTX 40 recently and I am disappointed with its >> image suppression when using built in laptop sound card. My ATS-3b is >> much better in this regard, being a classic superhetodyne with two >> NE612 and 4 crystal ladder filter. Need to say the software that I am >> using has very poor IQ calibration. >> > > You might try to use Linrad. It has the image suppression in the > frequency domain. > As far as I know it can be calibrated to any hardware that is > stable vs time although I have not actually tested soundcards > that deliver samples incorrectly due to drive routine bugs > (since I do not have ane such soundcard.) > > Linrad is a bit more complicated to learn to use properly > but it has sharp tools for interference fighting so it > could be worth the investment in time. I have started to > write "Linrad for newcomers" as an attempt to make it > easier for newcomers, but what you can find today at this link: > http://www.sm5bsz.com/linuxdsp/usage/newco/newcomer.htm > is far from complete. The main link for Linrad is: > http://www.sm5bsz.com/linuxdsp/linrad.htm > > 73 > > Leif / SM5BSZ > > ------------------------------------ > > Yahoo! Groups Links > > > > > >
