I've always been surprised that someone has placed a high quality Sowter mike transformer directly to the outputs of a QSD (And unless someone does it this summer, I'll be the first but using some old, but excellent Peerless/Lansing transformers) ... you get noiseless gain, excellent balance and phase and can follow it with a single ended opamp circuit with optimum noise impedance if more gain is needed
Main drawbacks are size and cost ($100+ per transformer) JR --- In [email protected], KD5NWA <[EMAIL PROTECTED]> wrote: > > I think the clue is that it takes a analog signal in and outputs a > digital representation hence A/D. > > If one follows the same procedure as when designing a RF-amp then it > will be a good thing. Only enough gain to overcome the circuit noise, > then your dynamic range is much better. > > On Fri, 2006-06-09 at 05:31 -0700, FRANCIS CARCIA wrote: > > I use minimum gain in the op amps after the detector to get maximum dynamic range. > > BTW Sound card codec is an A/D. frank > > > > "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote: > > Alberto: > > > > Over at the very controversial group softrock40 group. I suggested once that they could add analog to digital convertors right after the quadrature detector and so they seemed to have took off on that idea for awhile. It seems like it was an idea some of them had also been previously pondering: I do not know. Anyways it seems like a logical evolution of the circuit ideas. > > > > I terms of software now. Would there be an advantage in using the A/D right after the detector in your view and could the signal still be sent through the sound card? I realize that this would one day mean a new kind of software. If it is not immediately advantagous to explore then we can just dismiss that idea till some other date. > > > > Anyways if the A/D idea is not something ready for SDR at this time then we need to focus on the analog output of the quadrature detector as it is and go from there. {Some are still fussing over what sort of technology to use as the local oscillator and bandpass tuner sections.} Yet some have looked at the idea now and so it will not be something new one day down the road. It seems however that some very fast digital radio communications could result from the idea. Yet, as with anything no doubt it will have its peculiar problems also. > > > > ka9rza > > > > __________________________________________________________ > > Call Anyone, Anytime, Anywhere in the World - FREE! > > Free Internet calling from NetZero Voice > > Visit http://www.netzerovoice.com today! > > > > > > > > > > > > > > [Non-text portions of this message have been removed] > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > -- > > Cecil > KD5NWA > www.qrpradio.com > ------------------------ Yahoo! Groups Sponsor --------------------~--> Home is just a click away. Make Yahoo! your home page now. http://us.click.yahoo.com/DHchtC/3FxNAA/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/
