Tuned radio frequency amplifier with back to back varactor diodes connected through a common cathode lead

A tuned radio frequency amplifier for use with a signal receiving antenna, the tuner comprising, in combination:

• a first pair of varactor diodes, each having a cathode and an anode, said cathodes being connected together in a first common connection;
• a first inductor connected between the anodes of said first pair, the inductor being adapted for connection to the antenna to receive a signal therefrom;
• signal amplification means having an input and an output;
• a second pair of varactor diodes, each having a cathode and an anode, said cathodes being connected together in a second common connection;
• a second inductor connected between the anodes of the second pair, said second inductor comprising an output for the amplifier;
• means for providing a variable regulated tuning voltage to the first and second common connections;
• and
• means connecting the input of the signal amplification means to the first common connection and the output of the signal amplification means to the second common connection, whereby the first pair of varactor diodes forms a first tuned circuit with a first inductor for the input of the signal amplification means and the second pair of varactor diodes forms a second tuned circuit with the second inductor for the output of the signal amplification means, a smaller range of tuning voltage being required for a given range of tuned frequencies than would be required if the input and output of the signal amplification means were connected to anodes of the first and second pairs of varactor diodes.