Patents by Inventor David James Reginald Martin

David James Reginald Martin has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Apparatus for determining the position of a object
    Patent number: 4041495
    Abstract: The position of an object which moves along a fixed path is determined by measuring the phase displacement of two signals received from demodulators connected to an aerial located along the path. A transmitter carried by the objects feeds signals to the demodulators and one of these sends a demodulated signal direct to a comparator while the other sends its signal to the comparator along the aerial.
    Type: Grant
    Filed: September 4, 1975
    Date of Patent: August 9, 1977
    Assignee: Coal Industry (Patents) Limited
    Inventor: David James Reginald Martin
  • Communication system between a transmitter, receiver station and a mobile station utilizing unidirectional amplifiers between parallel radiated transmission lines
    Patent number: 4012662
    Abstract: A leaky feeder radio transmission system uses twin feeders connected respectively to a transmitter and receiver at a base station. The feeders are connected at intervals by uni-directional amplifiers which, alternately along the lines, are connected for conduction in opposite directions. Filters are positioned in the line between amplifier connection points. A mobile station adjacent to the feeders receives signals at one frequency from the feeders and transmits signals at a second frequency.
    Type: Grant
    Filed: February 13, 1976
    Date of Patent: March 15, 1977
    Assignee: Coal Industry (Patents) Limited
    Inventor: David James Reginald Martin
  • Radiating telecommunication systems
    Patent number: 3979674
    Abstract: A telecommunication system used in a mine has a long aerial along a tunnel which radiates signals to a mobile station. Signals from the station are radiated back to the line. Repeaters are included along the line to make up power losses. A connection of an extra length of line is made on the output side of each repeater and extends back parallel to the line for a distance of up to half the distance between adjacent repeaters. This extra line reduces the attenuation of signal power between repeaters.
    Type: Grant
    Filed: June 12, 1975
    Date of Patent: September 7, 1976
    Assignee: Coal Industry (Patents) Limited
    Inventor: David James Reginald Martin
  • Radiating telecommunication systems switching
    Patent number: 3979673
    Abstract: A telecommunication system uses a long main transmission line which extends from a base station and has repeaters along its length. A parallel line is divided into sections corresponding in length to the distance between repeaters. Selected sections are connected in parallel with the main line through switches which operate at about a 3 kHz frequency. The switching operation reduced alternations in the main signal and mitigates problems arising from standing waves.
    Type: Grant
    Filed: June 12, 1975
    Date of Patent: September 7, 1976
    Assignee: Coal Industry (Patents) Limited
    Inventor: David James Reginald Martin
  • Radiating transmission lines
    Patent number: 3949329
    Abstract: A leaky feeder coaxial cable has the inductance of the outer conductor altered by winding an extra conductor on the outer conductor or by physically forming the outer conductor so that it is unsymmetrical.
    Type: Grant
    Filed: January 22, 1974
    Date of Patent: April 6, 1976
    Assignee: Coal Industry (Patents) Ltd.
    Inventor: David James Reginald Martin