Interlinking system for traffic actuated control apparatus

Claim 1

AN INTERLINKING SYSTEM FOR TRAFFIC CONTROL APPARATUS OF THE TYPE HAVING A LOCAL TRAFFIC SIGNAL CONTROL OPERATED IN RESPONSE TO INFORMATION RECEIVED FROM A REMOTE MASTER CONTROL UNIT WHICH RECEIVES INFORMATION AS TO VEHICLE FLOW FROM ONE OR MORE SAMPLING POSITIONS INCLUDING IN COMBINATION: A SAMPLING DETECTOR; A DETECTOR UNIT COMPRISING AN IMPULSE GENERATOR OF THE TYPE HAVING AN OUTPUT OF PULSES OF CONTROLLED LENGTHS IN RESPONSE TO SIGNALS RECEIVED FROM SAID SAMPLING DETECTOR, A WAVE TRAIN GENERATOR WHICH PROVIDES A SERIES OF SQUARE PULSES IN RESPONSE TO EACH PULSE RECEIVED FROM SAID IMPULSE GENERATOR, AN IDENTIFICATION OSCILLATOR HAVING A SUBSTANTIALLY STABLE FREQUENCY OF OPERATION WHICH IDENTIFIES THE WAVE TRAIN GENERATOR WHICH ACTIVATES THE IDENTIFICATION OSCILLATOR IN ACCORDANCE WITH PULSES RECEIVED FROM THE WAVE TRAIN GENERATOR; A REMOTE MASTER CONTROL UNIT INCLUDING A FILTER DESIGNED TO PASS ONLY THE FREQUENCY OF SAID IDENTIFICATION OSCILLATOR, A DECODER MEANS FOR SUPPLYING A SERIES OF PULSES WHEN ENERGIZED BY THE OUTPUT OF SAID FILTER TO IDENTIFY SAID SAMPLING DETECTOR SIGNAL, A MASTER CONTROL MEANS FOR RECEIVING THE SERIES OF PULSES FROM SAID DECODER UNIT AND FOR INTERPRETING THE SAME, AND OSCILLATOR FOR PRODUCING A REFERENCE FREQUENCY VOLTAGE, A REFERENCE FREQUENCY CARRIER OSCILLATOR, MEANS FOR MODULATING SAID REFERENCE FREQUENCY VOLTAGE ON SAID REFERENCE FREQUENCY CARRIER, A COMBINING CIRCUIT CONNECTED FOR RECEIVING THE OUTPUT OF SAID MODULATOR, A CONTROL FREQUENCY SIGNAL CARRIER FREQUENCY OSCILLATOR, A SECOND MODULATOR, MEANS FOR GENERATING A CONTROL FREQUENCY SIGNAL VOLTAGE VARYING IN PHASE WITH RESPECT TO SAID REFERENCE FREQUENCY IN ACCORDANCE WITH INFORMATION RECEIVED FROM SAID MASTER CONTROL, MEANS FOR CONNECTING THE OUTPUT OF SAID CONTROL FREQUENCY SIGNAL VOLTAGE FOR MODULATING SAID CONTROL FREQUENCY SIGNAL CARRIER FREQUENCY AT SAID SECOND MODULATOR, MEANS FOR CONNECTING THE OUTPUT OF THE SECOND MODULATOR TO SAID COMBINING CIRCUIT, A PLURALITY OF FIXED FREQUENCY OSCILLATORS HAVING AN OUTPUT MEANS CONNECTED TO SAID COMBINING CIRCUIT, MEANS FOR CONTROLLING OSCILLATORS OF SAID PLURALITY FROM SAID MASTER CONTROL, MEANS FOR CONNECTING THE OUTPUT OF SAID IDENTIFICATION OSCILLATOR TO THE INPUT OF SAID FILTER; A LOCAL CONTROL UNIT COMPRISING A PLURALITY OF INPUT FILTERS EACH DESIGNED TO PASS A SUBSTANTIALLY SINGLE FREQUENCY, A SIGNAL CONTROL MEANS, ONE OF SAID FILTERS DESIGNED TO PASS SAID CONTROL FREQUENCY CARRIER, ANOTHER OF SAID FILTERS DESIGNED TO PASS SAID REFERENCE FREQUENCY CARRIER, THE REMAINING FILTERS DESIGNED TO PASS THE FREQUENCIES OF SAID PLURALITY OF OSCILLATORS; MEANS INCLUDING DEMODULATORS FOR DERIVING THE CONTROL FREQUENCY SIGNAL AND REFERENCE FREQUENCY SIGNAL RESPECTIVELY FROM THE RESPECTIVE CARRIER OUTPUTS FROM SAID ONE AND SAID ANOTHER FILTERS AND FOR SUPPLYING THE DEMODULATED REFERENCE AND CONTROL FREQUENCY TO SAID SIGNAL CONTROL, AND MEANS FOR SUPPLYING THE OUTPUT OF SAID REMAINING FILTERS TO SAID SIGNAL CONTROL; MEANS FOR TRANSMITTING THE OUTPUT OF SAID COMBINING CIRCUIT TO THE INPUT OF SAID PLURALITY OF FILTERS; AND A TRAFFIC SIGNAL CONTROLLED BY SAID SIGNAL CONTROL.