Identification of vehicles
First Claim
1. A vehicle adapted to cooperate with a roadway loop having a predetermined resonant frequency, said vehicle having an insulated multi-turn vehicle loop arranged on the vehicle to form a transformer with the roadway loop when said vehicle loop is in proximity to the roadway loop;
- means for tuning the vehicle loop to form a vehicle loop circuit resonant at a first frequency which is substantially the resonant frequency of the roadway loop; and
means for modulating the vehicle loop circuit at a second frequency;
different from said first frequency whereby, when said loops are in proximity to one another, a signal modulated at said second frequency is induced from the vehicle loop into said roadway loop for the identification of said vehicle.
0 Assignments
0 Petitions
Accused Products
Abstract
In a vehicle, an insulated multi-turn vehicle loop arranged to form a traormer with any roadway loop when said loops are in proximity; means for tuning the vehicle loop to form a vehicle loop circuit resonant at a first frequency; and means for modulating the vehicle loop circuit at a second frequency; whereby, in use, a signal modulated at said second frequency can be induced from the vehicle loop into any said roadway loop for the identification of said vehicle; and vehicle identification means comprising a roadway loop upon or in the surface of a roadway; means for tuning the roadway loop; means for energizing the roadway loop at a first frequency at least near to the resonant frequency of the tuned roadway loop; and a vehicle identification circuit having demodulation means and frequency detection means arranged to detect in the roadway loop any signal at the first frequency modulated at a second frequency, said second frequency being produced for the identification thereof by a vehicle as aforesaid and the first frequency being common to the roadway loop and the vehicle.
-
Citations
21 Claims
-
1. A vehicle adapted to cooperate with a roadway loop having a predetermined resonant frequency, said vehicle having an insulated multi-turn vehicle loop arranged on the vehicle to form a transformer with the roadway loop when said vehicle loop is in proximity to the roadway loop;
- means for tuning the vehicle loop to form a vehicle loop circuit resonant at a first frequency which is substantially the resonant frequency of the roadway loop; and
means for modulating the vehicle loop circuit at a second frequency;
different from said first frequency whereby, when said loops are in proximity to one another, a signal modulated at said second frequency is induced from the vehicle loop into said roadway loop for the identification of said vehicle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- means for tuning the vehicle loop to form a vehicle loop circuit resonant at a first frequency which is substantially the resonant frequency of the roadway loop; and
-
12. Vehicle identification means comprising a roadway loop disposed adjacent the surface of a roadway;
- means for tuning the roadway loop;
means for energizing the roadway loop at a first frequency at least near to the resonant frequency of the tuned roadway loop; and
a vehicle identification circuit coupled to said tuned roadway loop, said identification circuit having demodulation means and frequency detection means arranged to detect in the roadway loop any signal at the first frequency modulated at a second frequency, said second frequency being produced by a vehicle to be identified and which has a vehicle loop circuit thereon that is resonant at substantially the resonant frequency of said roadway loop and that has its impedance modulated at said second frequency. - View Dependent Claims (13, 14, 15, 16, 17)
- means for tuning the roadway loop;
-
18. A system, for the identification of a vehicle, comprising a roadway loop located adjacent the surface of a roadway;
- means for tuning the roadway loop; and
means for energizing the roadway loop at a first frequency at least near to the resonant frequency of the tuned roadway loop;
at least one vehicle to be identified when said vehicle is on said roadway, said vehicle having an insulated multi-turn vehicle loop arranged to form a transformer with the roadway loop when said loops are in proximity;
means on said vehicle for tuning the vehicle loop to form a vehicle loop circuit resonant substantially at said first frequency;
means on said vehicle for modulating the vehicle loop circuit at a second frequency; and
a vehicle identification circuit coupled to said roadway loop and having demodulation means and frequency detection means arranged to detect in the roadway loop any signal at the first frequency modulated at the second frequency. - View Dependent Claims (19, 20, 21)
- means for tuning the roadway loop; and
Specification