I've been thinking about that for a long time but have never done anything about it. Mouser has some transformers that I keep book-marked in case I decide to order them. They are flat from 200Hz to 100KHz with .5dB, it's hard to get any better than that. They cost about $14 each and you would need two, I keep ordering things from Mouser but I don't add them in because the are never in stock so it would hold up my order.
< http://www.hammondmfg.com/pdf/5c0042.pdf > I just looked at Mouser, I should have bought them before, now there is a ten device minimum order. At 12:58 PM 6/10/2006, you wrote: >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 Links > > > > Cecil Bayona KD5NWA www.qrpradio.com "Windows the worlds most successful software virus" ------------------------ Yahoo! Groups Sponsor --------------------~--> You can search right from your browser? It's easy and it's free. See how. http://us.click.yahoo.com/_7bhrC/NGxNAA/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/
