Hello Daniel, Thanks you very much for your design files. I do a lot of my work with LTSPICE, too.
.. > http://groups.yahoo.com/group/soft_radio/files/SDR%20Spice%20Analysis%20Files/SDR_I-Q_LTSpice.zip .. > So far, I have been exploring the use of small signal transistors as > low level I - Q interstage drivers and I - Q impedance matching > drivers. Some of the circuits will work well for matching the LO IN > oscillator to a mixer such as the MC 1496. My neighbor Joan EA3FXF has a very old magazine (1964) with a "RC 90 degree phase splitter" SSB exciter. You can view it on-line here: http://ea3fxf.googlepages.com/_0129175443_001.pdf The circuit is reversible and you can use it for reception purposes. Maybe can be useful for you. Good luck! Eduardo, EA3GHS http://ea3ghs.googlepages.com
