US 4,230,992 AGranted

Remote control system for traffic signal control system

AssigneeMinnesota Mining and Manufacturing Company

InventorJohn A. Munkberg

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Abstract

A multiple priority remote control system for the remote control of a traffic signal control system for a traffic intersection responsive to optical signals transmitted by optical energy transmitters carried on designated vehicles operating along the roadways of the intersection. The remote control system includes signal discriminator circuitry for producing high or low control signals dependent upon the particular optical signal that is detected and in accordance with the roadway of the intersection from which the detected optical signal is received. A control circuit connected to the controller for the traffic signal control system and to the discriminator circuitry responds to the control signals to provide a green light to the vehicle transmitting the first of two detected low priority signals or the first of two detected high priority signals or the high priority signal of detected high and low priority signals. The signal discriminator means includes a signal discriminator circuit which provides a delay and a coincidence circuit for a received signal to detect the high priority signals. A signal cancel counter and reset signal circuit is included in the signal discriminator circuit for enhancing the degree of signal discrimination.

Claims3

Dependent claims

A signal discriminating circuit for providing a control signal only in response to a consecutive predetermined number of input signals presented at a predetermined frequency, the circuit including

a digital delay circuit;
a coincidence circuit;
an input synchronizing circuit portion for receiving the input signals and having its output operatively connected to the input of said delay circuit and to an input of said coincidence circuit, said delay circuit having its output operatively connected for providing an input signal to said coincidence circuit, said coincidence circuit portion providing a coincidence indicating signal each time coincidence occurs between a signal from the output of said synchronizing circuit portion and a signal from the output of said delay circuit portion.
means operatively connected to said coincidence circuit and said delay circuit and responsive to one of said signals from the output of said coincidence circuit for preventing said coincidence circuit from providing another one of said signals at its output for a time period equal to the delay time of said delay circuit;
a signal counter operatively connected to the output of said coincidence circuit, each signal from the output of said coincidence circuit increasing the count of said signal counter by one, said signal counter providing the control signal whenever a consecutive predetermined number of signals from said coincidence circuit is received;
and
a pulse generator connected for providing timing pulses to said input synchronizing circuit, said digital delay, said coincidence circuit, and said means operatively connected to said coincidence circuit and said delay circuit.

4 more elements

Dependencies are inferred from the claim text.