Also see this link: http://www.seboldt.net/k0jd/phase_notes.html for info on a twisted-wire quadrature hybrid arrangement used in one variant of the R2/T2 receiver/transmitter.
-Ray WB6TPU -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, April 11, 2006 8:09 AM To: [email protected] Cc: [EMAIL PROTECTED] Subject: [soft_radio] link to file that explains transformer used in receiver for SDR 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 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/
