Hello Bob, I am very interested to build a high performance SDR for 6m but there is not much information.
The SDR-100 does 6m, but no numbers are published. Up to which frequency does the QSD works. What kind of performance could be achievable? Jean-Claude Abauzit, PJ2BVU --- In [email protected], Robert McGwier <[EMAIL PROTECTED]> wrote: > > Juan: > > The answer is, at is always is, it depends. Are you building an HF > receiver/transmitter/transceiver? It is extremely difficult to get > A/D's with sufficient dynamic range, good linearity numbers, and good > noise floor to operate at reasonable IF's. If you want to think of this > way the QSD and Tayloe are both sample and hold circuits but with > outstanding numbers for dynamic range, linearity and noise floor. It > will be pretty hard for you to beat the 10.7 MHz IF you build out of a > QSD mixer. > > Then you begin to study the problem even more closely. And you find > that it is really hard to build RF amps and mixers and IF amps in front > of the QSD that do not seriously hamper the performance. > > Read the receiver performance numbers for the NC2030 or the ARRL > measured numbers for the QSD in the SDR-1000 > > http://www.flex-radio.com/articles_files/2005-10_QST_Review.pdf > > > and you see that it is really hard to see how you can beat just doing > the QSD and doing ADC/DSP at near audio. > > N8BV, Phil Covington has published a very interesting variant. It has > some unique attributes. It is not the QSD (balanced) or the Tayloe > (unbalanced). It does not use sampling capacitors but active LPF's and > virtual ground: > > http://pcovington.blogspot.com/ > > He is doing several very interesting things and has done some great > stuff for the PowerSDR project as well. It is absolutely amazing to me > how much there is yet to learn in this fascinating area. > > Bob > N4HY > > > > Juan EA7FNJ wrote: > > >Hi guys. > > > >I have a question: > > > >What is the best way: > > > >- Input the IF signal to a ADC and make all the process by DSP > > > > or > > > >- Input the I/Q signal from the Tayloe Mixer to a ADC and DSP > > > >??? > > > >At te begin of this summer, I made a USB Modulator by a DSP TMS320C > >because it was a little project of my career. What is the best way in > >a SDR? > > > >73 > > > > > > > > > > > > > > > > > >Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > > > -- > Laziness is the number one inspiration for ingenuity. Guilty as charged! > ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/ELTolB/TM --------------------------------------------------------------------~-> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
