Frequency selective networks

Claim 1

IN AN ELECTRICAL FREQUENCY SELECTIVE SYSTEM RESPONSIVE TO AN ALTERNATING VOLTAGE INPUT PRESENTING SIMULTANEOUSLY A BASE FREQUENCY AND AT LEAST ONE SECONDARY FREQUENCY GREATER THAN SAID BASE FREQUENCY OF ALTERNATION, A PARALLEL RESONANT CIRCUIT CONNECTED TO BE ENERGIZED BY CURRENT DERIVED FROM SAID INPUT, SAID PARALLEL RESONANT CIRCUIT BEING DESIGNED TO RESONATE AT A PRESELECTED FREQUENCY GREATER THAN SAID BASE FREQUENCY, A SERIES RESONANT CIRCUIT CONNECTED TO BE ENERGIZED BY CURRENT DERIVED FROM SAID INPUT, SAID SERIES RESONANT CIRCUIT BEING DESIGNED TO RESONATE AT SAID PRESELECTED FREQUENCY, SAID SERIES RESONANT CIRCUIT INCLUDING A PARALLEL RESONANT PORTION DESIGNED TO RESONATE AT SAID BASE FREQUENCY, SAID SERIES CIRCUIT HAVING MINIMUM IMPEDANCE TO UNIDIRECTIONAL CURRENT, AND TRANSLATING MEANS INCLUDING A PAIR OF ELEMENTS, A FIRST OF SAID ELEMENTS BEING CONNECTED FOR ENERGIZATION IN ACCORDANCE WITH THE CURRENT FLOWING THROUGH SAID PARALLEL CIRCUIT AND THE SECOND OF SAID ELEMENTS BEING CONNECTED FOR ENERGIZATION IN ACCORDANCE WITH THE CURRENT FLOWING THROUGH SAID SERIES CIRCUIT, SAID SECOND ELEMENT BEING OPERABLE UPON ENERGIZATION TO RENDER SAID FIRST ELEMENT INEFFECTIVE.