The differential common base oscillator was correct! Unfortunately, it was as difficult as it seemed to be earlier this day.
BUT: I even dreamt of the right solution: define oscillation of the two single ended oscillators is in opposite phase and insert a virtual ground – et voila: easy, just as the single ended version. Considering the fact that I start dreaming of solutions that early in my thesis… how will it be shortly before I have to hand it in?!?
Tomorrow I should be able to finish basic theory on differential oscillators and so I can start with simulations and theory on coupling! Cadence here I come! 😀
By the way: my calculations stretched over 4 pages. My supervisor found it very funny. And his colleagues, whom he immediately told, too… of course…
“You did that by hand?” – “Yes? How else?” – “MatLab?” – *cry*