The output electrode of a field effect transistor of a high-frequency input stage is connected to a capacitively coupled input (gate) electrode of the field effect transistor of a mixer stage through one of a pair of bifilarly wound coils provided on a ferrite core, while the second of these coils connects...http://www.google.de/patents/US4313222?utm_source=gb-gplus-sharePatent US4313222 - H-F Portion of TV receiver
