If only more software authours would provide their audio drive in stereo I/Q form it would make direct upconversion a real doddle. If the signals were generated at baseband, even poor I/Q balance would not be too serious, as the image then lies on top of the wanted signal.
For narrow band modes, say no more than a couple of hundred Hz wide, a simple two opamp allpass network can be used to generate quadrature signals. 40dB isolation can be managed without too much effort. http://www.g4jnt.com/IQConverters.htm This is the soluition I use for generating linear 137 and 500kHz RF. http://www.g4jnt.com/LFUpconv.pdf Andy G4JNT --- In digitalradio@yahoogroups.com, "obrienaj" <k3uka...@...> wrote: > > "I am developing a 'modem' to directly modulate computer generated modes to > RF thus eliminating the requirement of using a transceiver audio input" > > > Welcome to the group, tell us more. > > Andy K3UK >
