Unitary tuning structure

Abstract From the Canadian patent

An RF signal input circuit for a UHF tuner of a television receiver comprises a series-tuned circuit including a varactor diode and an inductance element connected in series, in the order named between signal, ground and a gate electrode of a field-effect transistor RF amplifier. The series-tuned circuit has a relatively uniform bandwidth throughout the UHF range. A capacitor connected in shunt with the gate electrode completes a "split-capacitor" configuration in which the varactor diode and the shunt capacitor form a variable impedance transformation network for making the relationship between the effective impedances of the series-tuned circuit and FET amplifier relatively uniform …