That is not a new idea to a lot of people, specially those that have been involved in radio for a long time. The way it was stated it made people think of a conventional transformer that will not give you Quadrature. The "transformer" is only part of the circuit. It's not a transformer in the conventional form but a transmission line used in a bridge configuration.
It's basically a LC bridge with a high pass filter on one side and a low pass on the other. It will indeed generate a Quadrature over a reasonable frequency range. I have schematics on my web site using similar principles to generate Quadrature signals over several bands. They are the QSB2 LTSpice schematics. The old stuff never dies it just gets recycled. This has been talked about in the past on this SoftRock list, where I mentioned it in connection with generating Quadrature signals over a wide range of frequencies. If the components are reasonably matched as one side changes phase with frequency the other changes also and the outputs stay at 90 degrees to each other. This circuitry dates back to the 50's where it was used in early SSB equipment of the phasing type. At 10:09 AM 4/11/2006, you wrote: >Leon: > >http://www.nitehawk.com/rasmit/quad_mixers.zip > > Here is a link to a file I did on the receiver that contains the > transformer and you can see how it was originally used. The > circuit is featured in the 2005 ARRL HB. From that you can see why > I have the question of how it might be used in the example I put > forth to Alberto. So far the idea of the transformer seems new > here and even out of left field. > > The transformer splits and shifts the Local Oscillator that goes > to two IC's that contain mini mixing transformers with a diode each > for the I and Q outputs. However I was able to see quickly that > you could also replace the ICs with two dual gate Mosfets as high > gain mixers for the I Q outputs. > > This might explain some of the unusual views I have had and maybe > some have not understood exactly my views on the receiver designs > because I have this circuit in my mind. You can buy the receiver > by search engine-ing for Rick Campbell or the Biaural Receiver. > > The originally application was for an experimental receiver that > has a stereo like feel to it as you tune around with ear > phones. However it is based upon splitting and phase shifting the > carrier into I and Q outputs and so creates another way to achieve > the I Q needed for use with SDR. > > I think this file will explain why I have had such unusual > questions about ideas for receiver designs. The transformer then > is an application that reduces down allot of complexity and allows > you to use a sine wave from a simple crystal oscillator or a vfo as > the LO input. One can choose to use balanced mixer ICs or a Mosfet > or even see why I have thought of using the transformer alone where > there is already a low frequency: but it seems to me that I might > need the mixing products of a mixer even in this case? > >Dan > > >_____________________________________________________________________ >Call Anyone, Anytime, Anywhere in the World - FREE! >Free Internet calling from NetZero Voice >Visit http://www.netzerovoice.com today! > > > > > >Yahoo! Groups Links > > > > Cecil Bayona KD5NWA www.qrpradio.com I fail to see why doing the same thing over and over and getting the same results every time is insanity: I've almost proved it isn't; only a few more tests now and I'm sure results will differ this time ... [Non-text portions of this message have been removed] 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/
