Class / Patent application number | Description | Number of patent applications / Date published |
375218000 | EARTH OR WATER MEDIUM | 10 |
20080240209 | Sub-Surface communications system and method - A communications system including: a plurality of sub-surface portable transceivers each including: a digital data source, a modulator coupled to the digital data source, a power amplifier coupled to the modulator and a loop antenna inductively coupled to the power amplifier; and a base transceiver including: an electrically insulated ferrite core antenna for receiving magnetic signals, an electric di-pole antenna for receiving ambient noise, a noise canceller coupled to the insulated ferrite core antenna and electric dipole antenna and responsive to the electric-dipole antenna to filter noise from signals received via the insulated ferrite core antenna, a demodulator coupled to the noise canceller and a decoder coupled to the demodulator. | 10-02-2008 |
20100322293 | COMMUNICATION BETWEEN SUBMERGED STATION AND AIRBORNE VEHICLE - The present invention discloses a system for digitally modulated radio communication directly between a submerged underwater station and an airborne station. Each of the underwater station and the airborne station has or is associated with a radio communications antenna. Suitable radio communications antennas include loop antennas, solenoid antennas, stacked multiple loop antennas, planar arrayed loop antennas, a multiple resonant loop antennas. In some embodiments, the communications antennas of the submerged underwater station and the airborne station are each deployed horizontally thereby improving the efficiency of the signal transfer between the submerged underwater station and the airborne station. | 12-23-2010 |
20120076178 | Portable Wireless Through-The-Earth Communication System - A portable wireless through-the-earth bi-directional communication system for sending and receiving text data using ultra-low-frequency electric current and the earth as the conductive media. A surface controller which executes application software which controls the communication functions of the system. A surface receiver and surface transmitter are connected to sets of electrodes which provide the electric current, and are in communication with the surface controller. Text data are encoded into data packets, modulated onto ultra-low-frequency electric carrier waves, and transmitted through the earth by the surface electrodes to a subsurface transceiver. The subsurface transceiver demodulates, converts and displays incoming signals into text messages. The subsurface transceiver has a user interface to allow subsurface users to submit text data to the surface receiver. The transceiver converts the text data into analog data packets, modulates the packets onto ultra-low-frequency carrier waves, and transmits the signal to the surface receiver. | 03-29-2012 |
20130208768 | UNDERWATER ACOUSTIC MULTIPLE-INPUT/MULTIPLE-OUTPUT (MIMO) COMMUNICATION SYSTEMS AND METHODS - Methods and systems for acoustic multiple-input/multiple-output (MIMO) communication in an underwater environment. The method includes: a) receiving signals at multiple receivers representing transmitted signals from multiple transmitters, b) estimating channel responses between the multiple receivers and the multiple transmitters, c) performing an initial demodulation process on the received signals using the estimated channel responses to remove inter-symbol interference (ISI), and d) performing at least one subsequent demodulation process on the received signals. The subsequent demodulation process: i) removes co-channel interference (CoI) using the estimated channel responses and demodulated signals from an immediately preceding demodulation process to form interference cancelled signals and ii) removes ISI from the interference cancelled signals. In the initial and subsequent demodulation processes, ISI removal includes a time reversal combining process followed by a single-channel decision feedback equalization (DFE) process. | 08-15-2013 |
20140036968 | Reducing noise in a sequence of data by linear and non-linear estimation - A method of reducing noise in a sequence of data by linear and non-linear estimation. The method includes receiving a noisy sequence of data indicative of a sequence of physical events; applying a non-linear technique to the noisy sequence to obtain an approximation of a noise-free sequence of data; subtracting the approximation from the noisy sequence to obtain an estimate of noise in the noisy sequence of data; applying a linear technique to the estimate of noise to obtain a filtered sequence; and adding the filtered sequence to the approximation of the noise-free sequence to obtain a reduced-noise sequence of data indicative of the sequence of physical events. | 02-06-2014 |
20140044154 | Mobile device with an underwater communications system and method - A mobile device with an underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms. The portable device may be wearable. | 02-13-2014 |
20140098841 | UNDERWATER ACOUSTIC MULTIPLE-INPUT/MULTIPLE-OUTPUT (MIMO) COMMUNICATION SYSTEMS AND METHODS - Methods and systems for acoustic multiple-input/multiple-output (MIMO) communication in an underwater environment. The method includes: a) receiving signals at multiple receivers representing transmitted signals from multiple transmitters, b) estimating channel responses between the multiple receivers and the multiple transmitters, c) performing an initial demodulation process on the received signals using the estimated channel responses to remove inter-symbol interference (ISI), and d) performing at least one subsequent demodulation process on the received signals. The subsequent demodulation process: i) removes co-channel interference (CoI) using the estimated channel responses and demodulated signals from an immediately preceding demodulation process to form interference cancelled signals and ii) removes ISI from the interference cancelled signals. In the initial and subsequent demodulation processes, ISI removal includes a time reversal combining process followed by a single-channel decision feedback equalization (DFE) process. | 04-10-2014 |
20140169414 | METHOD FOR OPERATING A COMMUNICATION SYSTEM AND COMMUNICATION SYSTEM - A method for operating a communication system including a first device with a working oscillator and a second device with a reference oscillator is provided. The method includes calibrating the working oscillator of the first device connected to an asynchronous serial communications bus. The calibrating includes defining a measurement time, and measuring and selecting a predefined pulse space of a first signal. The predefined pulse space of the first signal is formed by a plurality of predefined discrete pulse spaces, generated by a second device including a reference oscillator, and received by the first device during the measurement time over the asynchronous serial communications bus. | 06-19-2014 |
20140314129 | VLF TRANSMIT ANTENNA SYSTEM, METHOD AND APPARATUS - There is provided a Very Low Frequency (VLF) transmit antenna system, method, and apparatus for creating a magnetic field at low frequencies suitable for communications through the earth or other thick, solid barriers. At least two loop antennas are arranged such that a magnetic field of each one of the at least two loop antennas passes through each remaining one of the at least two loop antennas, thereby closely coupling the at least two loop antennas. A full bridge Pulse Width Modulated transmitter is directly connected to each loop antenna for driving the latter. When a loop of a given loop antenna is broken and its magnetic field collapses, the transmitters connected to the remaining loop antennas increase the current in the remaining loops to maintain a constant magnetic field. | 10-23-2014 |
20220140917 | SYSTEM AND METHOD FOR GENERATING ELECTRIC BASED NON-LINEAR WAVES IN NATURAL TERRESTRIAL ENVIRONMENTS - A system for transmitting electrical signals through a terrestrial body, the terrestrial body having an upper surface, may include a transmitter. The transmitter may include a first electrode positioned proximate the upper surface of the terrestrial body and at least one second electrode positioned beneath the upper surface of the terrestrial body and spaced from the first electrode. The system may include a power source operable to supply power to the first electrode and the at least one second electrode. The system may include a receiver assembly spaced away from the transmitter. When power is supplied to the transmitter, the transmitter may be operable to propagate an electric non-linear wave signal through the terrestrial body. The receiver assembly may be operable to detect the electric non-linear wave signal. | 05-05-2022 |