I'm attempting to design a basic FSK transceiver (architecture shown below) using only discrete components (transistors, diodes, resistors, etc). My idea was to separate the two binary frequency components via band-pass filters but I'm having trouble figuring out how to get such a high-Q (i.e. narrow-band) effect. Most filter calculators suggest capacitor values in the femto-farad range, which is not possible for SMT MLCC's. Any thoughts would be appreciated.