Controllable rectifier receiver responsive to plural signal conditions

Claim 1

A SELECTIVE CONTROL CIRCUIT HAVING AN INPUT TERMINAL AND AN OUTPUT TERMINAL, SAID SELECTIVE CONTROL CIRCUIT PREVENTING THE PASSAGE OF ANY ELECTRICAL SIGNAL FROM SAID INPUT TO SAID OUTPUT TERMINAL IN THE ABSENCE OF A COMMAND SIGNAL OF PREDETERMINED POLARITY AND OF PREDETERMINED MINIMUM DURATION, SAID SELECTIVE CONTROL CIRCUIT COMPRISING SAID INPUT AND OUTPUT TERMINALS AND A COMMON REFERENCE LINE, A FIRST AND A SECOND CONTROLLABLE RECTIFIER CONNECTED IN SERIAL RELATIONSHIP BETWEEN SAID INPUT AND OUTPUT TERMINAL AND BOTH ARRANGED IN THE SAME CONDUCTING DIRECTION AND EACH HAVING A CONTROL ELECTRODE FOR INITIATING CONDUCTION THERETHROUGH, AN INPUT CIRCUIT FOR REJECTING SIGNALS OF THE OPPOSITE POLARITY AND FOR REJECTING ALTERNATING CURRENT SIGNALS ABOVE A PREDETERMINED FREQUENCY CONNECTED BETWEEN SAID INPUT TERMINAL AND SAID REFERENCE LINE INCLUDING A DIODE IN SERIES WITH AN ELECTROLYTIC CAPACITOR SHUNTED BETWEEN SAID INPUT TERMINAL AND SAID REFERENCE LINE, SAID DIODE BLOCKING CONDUCTION OF SIGNALS OF SAID PREDETERMINED POLARITY AND SAID ELECTROLYTIC CAPACITOR PROVIDING A LOW IMPEDANCE CONDUCTION PATH FOR SIGNALS OF SAID PREDETERMINED POLARITY, FIRST RESISTANCE MEANS CONNECTED ACROSS SAID DIODE AND SECOND RESISTANCE MEANS CONNECTED ACROSS SAID ELECTROLYTIC CAPACITOR, AN INTERMEDIATE POINT IN SAID FIRST RESISTANCE MEANS BEING CONNECTED TO THE TRIGGER ELECTRODE OF SAID FIRST CONTROLLABLE RECTIFIER DEVICE, WHEREBY A SIGNAL OF SAID PREDETERMINED POLARITY AND OF FREQUENCY BELOW SAID PREDETERMINED FREQUENCY WILL INITIATE CONDUCTION THROUGH SAID FIRST CONTROL-