Automatic antenna coupler fault detector and indicator

• US 5,257,407 A
• Filed: 09/20/1990
• Issued: 10/26/1993
• Est. Priority Date: 09/20/1990
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Heinzelmann, David W.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): PHAM, CHI H
• Application Number:
  US07/585,749
• Time in Patent Office: 1,132 Days
• Field of Search: 455/67.1, 455/67.7, 455/80, 455/82, 455/115, 455/117, 455/129, 455/226.1-226.4, 455/269, 455/280-282, 455/289, 455/292, 455/293, 324/538, 340/652, 340/664, 343/894, 343/905, 343/906
• US Class Current: 455/67.11
• CPC Class Codes: H04B 17/20 of receivers

Abstract

A communication system 100 comprising a dispatch sub-system 100A, a plurality of transmitters 100B, and a plurality of mobile transceivers 100C is disclosed. An antenna coupler 410 and a location sensor 414 are coupled to one another via a coax cable 412. The bias current to the coupler is supplied by the location sensor 414 via the resistor 406. A detector 200 measures the voltage across the resistor 406 which is relative to the current flowing in to the antenna coupler 410. The detector 200 compares the measured voltage via comparators 218 and 238 and determines if the measured voltage is beyond a certain boundary. The NOR gate 244 routes the comparison result to a MPU 250. The MPU 250 processes the result and transmits a signal to a base station 104 via the mobile transceiver 118. The base station 104 decodes the received signal and presents it to a dispatch center 106. A screen display 600 of a terminal at the dispatch center 106 has a dedicated column 602 for the presentation of the coupling status of the antenna coupler 410.

Claims

1. In a communication system having a plurality of transmitters for transmitting signals with pre-determined time intervals, also having a plurality of vehicles each having an antenna coupled to a receiver via an active transformation device being biased by a supply current from said receiver, said receiver intended for receiving and decoding said signals with pre-determined time intervals, a processor coupled to said receiver for processing said signals with pre-determined time intervals to determine geographical location of said plurality of vehicles, a transceiver coupled to said processor for transmitting signals containing said geographical location of said plurality of vehicles to a dispatch center, comprising:

a circuit for analyzing the coupling status of said receiver to said antenna, comprising;

measurement means for measuring said bias current;

comparator means coupled to said measurement means for comparing said bias current to pre-determined levels of current levels for determining the coupling status of said antenna to said receiver; and

indicator means coupled to said comparator means for indicating said coupling status of said antenna to said receiver to said transceiver.

2. The circuit of claim 1, further including:

processor means for processing the result of said comparator means;

3. The circuit of claim 2, wherein:

said measurement means includes a current to voltage converter.

4. The circuit of claim 3, wherein:

said current to voltage converter is a resistor.

5. The circuit of claim 2, wherein:

said processor means includes setting or clearing of a flag bit in a micro-processor in response to said coupling status of said antenna.

6. The circuit of claim 1, wherein:

said indicator means includes a display at said dispatch center.