A BACKBONE HIGHWAY COMMUNICATIONS SYSTEM USING COAXIAL CABLE

A PROBLEM OF PROVIDING THE COMMUNICATION LINK FOR MODERN HIGHWAY MANAGEMENT AND CONTROL, IN PARTICULAR, A 100-MILE SPAN OF HIGHWAY, IS ANALYZED FOR TYPICAL VOICE AND CONTROL FUNCTION REQUIREMENTS PLUS CLOSED CIRCUIT TELEVISION MONITORING CAPABILITY. BASED ON THIS ANALYSIS, THE NUMBER OF CHANNELS AND HENCE THE BANDWIDTH REQUIRED TO MEET REQUIREMENTS IS DEVELOPED. A COAXIAL CABLE SYSTEM CAN BEST PROVIDE THE BANDWIDTH AND ACCESS FLEXIBILITY THAT WILL BE NECESSARY FOR THE MANY LINKS REQUIRED FOR EFFECTIVE HIGHWAY MANAGEMENT. A COAXIAL CABLE SYSTEM AS A TRANSMISSION PATH IS TWO-DIMENSIONAL IN THAT IT INVOLVES ABSOLUTE SIGNAL LEVELS AS WELL AS SPECTRUM CONSIDERATIONS. AN ANALYSIS OF DISTORTION CHARACTERISTICS OF COAXIAL CABLE SYSTEMS IS INCLUDED TO ARRIVE AT SIGNAL TO NOISE-PLUS-DISTORTION RATIO VS. CABLE LENGTH AND AMPLIFIER GAINS. IT WAS CONCLUDED THAT 110 NARROW-BAND CHANNELS AND ONE VIDEO CHANNEL ARE REQUIRED TO PROVIDE THE SIGNALING, CALL BOX, AND VISUAL-MONITORING FUNCTIONS INTO THE CONTROL CENTER. ONLY 15 NARROW-BAND CHANNELS ARE REQUIRED TO PROVIDE THE SIGNALING AND CALL-BOX FUNCTIONS OUT OF THE CONTROL CENTER. BECAUSE OF THE MULTIPLE-ACCESS REQUIREMENTS ALONG THE HIGHWAY, THIS TRANSMISSION CAPABILITY CAN ONLY BE PROVIDED BY COAXIAL CABLE. A TWO-CABLE SYMMETRICAL SYSTEM WITH AN RF BANDWIDTH BETWEEN 5 AND 20 MHZ WAS SHOWN TO HAVE SIGNIFICANT RESERVE TRANSMISSION CAPABILITY. THE NARROW-BAND CHANNELS HAVE 25 KHZ SPACING AND ARE GROUPED BETWEEN 17 AND 20 MHZ WITH THE 6 MHZ VIDEO SIGNAL BETWEEN 5 AND 11 MHZ. THE LARGE GUARDBAND ELIMINATES PROBLEMS DUE TO SECOND-ORDER NONLINEARITIES WHICH WERE SHOWN TO BE MORE SEVERE THAN HIGHER-ORDER PROBLEMS. AN ALTERNATE MINIMUM HIGHWAY TRANSMISSION SYSTEM USING ONE RF COAXIAL CABLE WITH FREQUENCY SELECTIVE DIRECTIONAL COUPLERS IS ALSO DESCRIBED. A 100-MILE SYSTEM WAS ANALYZED FOR VARIOUS SIGNAL LEVELS AND THE RESULTANT DISTORTION AND NOISE LEVELS. THE TYPICAL COST OF ONLY THE TRANSMISSION PORTION OF THE COAXIAL CABLE SYSTEM INCLUDING AMPLIFIERS, 0.5-IN. DIAMETER COAXIAL CABLES, AND BURIAL LABOR IS $352,000 FOR A 100-MILE SPAN OF HIGHWAY. A SYSTEM MEETING THE MINIMUM HIGHWAY TRANSMISSION REQUIREMENTS WOULD COST APPROXIMATELY $100,000 LESS. THESE COSTS, HOWEVER, DO NOT INCLUDE THE MANY ITEMS WHICH MUST BE INCLUDED FOR A TOTAL SYSTEM. /AUTHOR/

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00189545
• Supplemental Notes:
  • Vol Vt-19, PP 50-58
• Authors:
  • Link, C N
• Publication Date: 1970-2

Media Info

• Serial:
  • IEEE Transactions on Vehicular Technology
  • Publisher: Institute of Electrical and Electronics Engineers (IEEE)
  • ISSN: 0018-9545
  • Serial URL: http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=25

Subject/Index Terms

• TRT Terms: Bandwidth; Closed circuit television; Coaxial cables; Communication systems; Costs; Distortion (Structures); Signal to noise ratio; Transmissions
• Uncontrolled Terms: Two dimensional
• Old TRIS Terms: Distortion
• Subject Areas: Finance; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00225867
• Record Type: Publication
• Source Agency: Traffic Systems Reviews & Abstracts
• Files: TRIS
• Created Date: Dec 2 1970 12:00AM