INDUCTIVE CARRIER COMMUNICATION SYSTEMS

• US 3,609,247 A
• Filed: 04/21/1967
• Issued: 09/28/1971
• Est. Priority Date: 04/21/1967
• Status: Expired due to Term

• Current Assignee: William S. Halstead
• Original Assignee: William S. Halstead
• Inventors: Halstead, William S.
• Primary Examiner(s): Claffy, Kathleen H.
• Assistant Examiner(s): Helvestine, William A.
• Application Number:
  US04/632,699
• Time in Patent Office: 1,621 Days
• Field of Search: 179/82,1VE
• US Class Current: 455/41.1
• CPC Class Codes: H04B 5/72 for local intradevice communication

Abstract

An integrated multiple-function communication system for highways, railroads and other applications, the system comprising a wideband coaxial trunk cable with associated amplifier/repeaters for long-distance point-to-point transmission of a plurality of carrier signals combined with inductivesignaling means including frequency converter/amplifiers each having an input physically coupled to the coaxial trunk cable and an output coupled to an inductive-signaling conductor, the latter disposed within the trunk-cable structure or electrically related thereto whereby a relatively uniform electromagnetic field of a desired strength is established along a highway or other service zone for inductive carrier communication with vehicles, roadside call boxes and other devices located in proximity to the cable which interconnects with a control or terminal point.

Claims

1. An inductive carrier communication system comprising a coaxial trunk cable, a carrier wave generator having an output circuit coupled to said coaxial cable, means for modulating carrier wave energy from said generator, a plurality of inductive-signaling transmission lines each of predetermined characteristic impedance and extending parallel to said trunk cable in sequential manner, coupling means disposed at intervals along said trunk cable connecting each of said inductivesignaling transmission lines to said trunk cable, said coupling means including means for regulating the amount of carrier wave energy applied to each of said inductive-signaling transmission lines, and termination means connecting the ends of each of said transmission lines whereby each of said transmission lines is terminated in its characteristic impedance to minimize undesired wave reflection and radiation of electromagnetic waves in space.

2. A communication system of inductive-signaling type for use along transportation routes such as roadways, railroads, waterways and the like comprising a carrier wave generator, means for modulating carrier wave energy from said generator, means coupling the output of said generator to a coaxial cable having a center conductor and a conducting sheath held at ground potential, said coaxial cable extending parallel to a transportation route served by the system, a plurality of inductive-signaling conductors extending sequentially along said route parallel to said coaxial cable, each of said inductive-signaling conductors having a coupling means connecting each of said inductive-signaling conductors to said center conductor whereby a controlled amount of carrier wave energy may be transferred from said center conductor to each of said inductive-signaling conductors, and terminating means connecting the end of each of said inductive-signaling conductors to said conducting sheath of said coaxial cable to minimize standing waves on said inductive-signaling conductors and effect relative uniformity of the external induction field extending about said last-mentioned conductors along the total length of route seRved by the system.

3. A transportation route communications system of inductive-signaling type comprising a carrier wave generator, means for modulating carrier wave energy from said generator, means coupling the output of said generator to a coaxial cable having a center conductor and extending parallel to a transportation route served by the system, dielectric means about said center conductor, a conducting sheath formed about said dielectric means and held at ground potential, an inductive-signaling conductor extending parallel to said coaxial cable for the length of a communication zone along said transportation route, coupling means intermediate said center conductor and said inductive-signaling conductor whereby a desired amount of carrier wave energy may be transferred from said center conductor to said inductive-signaling conductor, and terminating means at the end of said inductive signaling conductor, said terminating means connecting the end of said inductive-signaling conductor to said conducting sheat at ground potential.