Double tuned circuit with balanced output and image trap

Claim 1

In a television signal processing apparatus, tuning apparatus, comprising: means for amplifying RF signals and having an output coupled to a signal node with respect to a reference potential, a first tuned circuit including a first varactor diode responsive to a first tuning voltage and a first inductance element coupled from the signal node to a point of reference potential for selecting one of said amplified RF signals in response to the first tuning voltage, a second tuned circuit including a second varactor diode responsive to a second tuning voltage and a second inductance element for further selecting said one of said amplified RF signals in response to the second tuning voltage, said first and second tuned circuits forming a double tuned circuit, said first and second inductance elements being inductively coupled, the second inductance element having a pair of output terminals balanced with respect to the reference potential, a first trap capacitor coupled between one output terminal of the second inductance element and the signal node, and a second trap capacitor coupled between the other output terminal of the second inductance element and the reference potential, the first and second trap capacitors providing a notch frequency for the tuned RF signal at each of the pair of output terminals.