8442results about "Electromagnetic transmitters" patented technology

The present invention has been developed considering the above-described problems and aims to provide various structures and applications for illuminative light communication. According to the first aspect of the prevent invention, a broadcast system includes an LED light source 115 for lighting, a power line 103 that supplies electric power to the LED light source 115, a data modulator 102 that modulates and multiplexes a plurality of pieces of data, superimposes the resulting signal on an electric power waveform, and then transmits the resulting superimposed signal waveform to the power line 103, and a filter 112 that selectively separates one or more of a plurality of pieces of modulated data on the power line so as to control light intensity or blinking of the LED light source. Data is transmitted through changes in light intensity or blinking of the LED light source.

Using a transformation based at least in part on a non-simple orthogonal or unitary matrix, data may be transmitted over a data bus in a manner that is resilient to one or more types of signal noise, that does not require a common reference at the transmission and acquisition points, and / or that has a pin-efficiency that is greater than 50% and may approach that of single-ended signaling. Such transformations may be implemented in hardware in an efficient manner. Hybrid transformers that apply such transformations to selected subsets of signals to be transmitted may be used to adapt to various signal set sizes and / or transmission environment properties including noise and physical space requirements of given transmission environments.

A distributed antenna system (DAS) includes a multiple-input and multiple-output (“MIMO”) base station configured to output at least a first and second signal, and a hybrid coupler coupled thereto, the coupler configured to receive the first and second signal from the MIMO base station on respective first and second ports and provide an output signal on at least one output port, the output signal including at least a portion of the first signal and at least a portion of the second signal. The DAS further includes a master unit communicating with the coupler and configured to receive at least the output signal, and at least one remote unit communicating with the master unit and configured to communicate the output signal to a device.

This invention relates to the zonal transmission of data by optical means through the modulation of light from common building light fixtures, including the light output of fluorescent, mercury vapor, and other arc or discharge lamps and fixtures; a system for the reuse of radio frequencies by smart radios, and the accurate locating and tracking of objects or persons as they move through a building; by means of creating a communications system which exploits the existing infrastructure of a building to facilitate the transmission of relatively secure control and communications data via creation of a multiplicity of area-limited interference-free communication zones. The system facilitates the transmission of wide-area as well as zonal-specific data. The system facilitates the creation of a database that contains present location and history location and movement data of persons and objects as they move through a building.

This invention extends the range of optical data of mobile device by trading speed for distance as well as integrating a plurality of pulses over time to define a single bit of information. The present invention uses a number of integrated pulses to represent a single bit instead of utilizing a one to one correspondence between pulses and bits. The present invention executes a range extender application which executes on the mobile device without any hardware modification to the mobile device. The range extender application causes the optical transmitter to “stutter” or repetitively emanate the identical pulse representing a bit of information. Sufficient photons are thereby gathered at a receiver to reach a predetermined threshold. A tradeoff of the data transmission frequency in this invention is that a signal intensity drops by a factor of 100 when distance increases by a factor of 10 yielding a distance / intensity ratio of {fraction (1 / 10)}.

An optical data link includes first and second pluralities of transmission devices, at least one of which is configured as an array. A multichannel transmission link has a first end connected to the first plurality of transmission devices and a second end connected to the second plurality of transmission devices so as to form a plurality of parallel transmission channels therebetween. The multichannel transmission link includes a multicore fiber with a plurality of individual cores having a configuration matching the array configuration of the at least one plurality of transmission devices. The multicore fiber has an endface connected directly to the at least one plurality of transmission devices, with the individual cores of the multicore fiber aligned with respective devices in the at least one plurality of transmission devices. Further described are access networks and core networks incorporating a transmission link comprising at least one span of a multicore fiber.

Techniques for directly converting an electrical signal into an optical signal by using a whispering gallery mode optical resonator formed of a dielectric material that allows for direct modulation of optical absorption by the electrical signal.

A visible light communication apparatus enables an operator to visually recognize a communication state during visual light communication. The apparatus includes a light emitting section which emits visible light and which includes a modulator, a visible light emitter, a light emitting element and an emission control section which includes a controller and which controls an emission state of the visible light from the light emitting section. The apparatus controls the emission state according to the communication state. It is hence possible for the operator to visually perceive the communication state during the visible light communication.

In a visible light communication system, a transmission device includes a data modulation section which assigns 1-bit information to each of visible lights of RGB, and modulates transmission data into 3-bit modulation data. An LED light emission section transmits a multiplexed visible light signal, in which the RGB visible lights are multiplexed in accordance with the modulation data.

A visible light communications transmitter combines a modulated carrier signal with a pulse from a pulse generator. The carrier signal is modulated according to data read from a buffer during the pulse.

An optical transceiver includes a single integrated circuit chip to integrate the drive, receive, control, and monitoring functions of the optical transceiver. The single chip may further have an advance replacement algorithm and monitoring algorithm for the opto-electronic devices of the optical transmitter and receiver to generate flags and / or an advance replacement indication. Methods, apparatus, and systems are disclosed.

A signal transmission system includes an interface unit that monitors the operating condition of each device. The signal transmission system also includes a simulator that simulates the transmission quality of the system in response to the operating condition of each device, and controls each device so as to optimize the transmission quality.

A fiber optic transceiver adapted for use in an optical fiber data transmission system is capable of detecting reflection problems in fiber optic links and providing information related to the distance to the point of reflection. The fiber optic transceiver contains a fiber interface, a receiver, a transmitter, and a microcontroller. The microcontroller controls the transmitter to modulate the laser power to transmit impulse test data and the transceiver includes circuitry and microcode to detect reflection due to fiber connection problems. This enables trouble shooting during installation and / or reconfiguring the connection automatically, in response to a connection problem, and provides a physical layer link.

The present invention discloses a low-cost light source for optical transmission systems and optical networks based on wavelength-division multiplexing (WDM) technology. A light source in accordance with the present invention is implemented by externally injecting a narrow-band incoherent light into a Fabry-Perot laser diode (F-P LD). After injection of narrow-band incoherent light, the output of F-P LD becomes wavelength-selective rather than multi-mode and the output wavelength of F-P LD coincide with the peak wavelength of the injected incoherent light. Multi-channel WDM light sources according to the present invention can be implemented using a single broadband incoherent light source and plurality of F-P LDs. An optical transmission system for upstream signal transmission in an passive optical network using the light source according the present invention is also disclosed.

A coolerless photonic integrated circuit (PIC), such as a semiconductor electro-absorption modulator / laser (EML) or a coolerless optical transmitter photonic integrated circuit (TxPIC), may be operated over a wide temperature range at temperatures higher then room temperature without the need for ambient cooling or hermetic packaging. Since there is large scale integration of N optical transmission signal WDM channels on a TxPIC chip, a new DWDM system approach with novel sensing schemes and adaptive algorithms provides intelligent control of the PIC to optimize its performance and to allow optical transmitter and receiver modules in DWDM systems to operate uncooled. Moreover, the wavelength grid of the on-chip channel laser sources may thermally float within a WDM wavelength band where the individual emission wavelengths of the laser sources are not fixed to wavelength peaks along a standardized wavelength grid but rather may move about with changes in ambient temperature. However, control is maintained such that the channel spectral spacing between channels across multiple signal channels, whether such spacing is periodic or aperiodic, between adjacent laser sources in the thermally floating wavelength grid are maintained in a fixed relationship. Means are then provided at an optical receiver to discover and lock onto floating wavelength grid of transmitted WDM signals and thereafter demultiplex the transmitted WDM signals for OE conversion.

A wireless communication system transmits data on multiple carriers simultaneously to provide frequency diversity. Orthogonality is provided by carrier interference, which causes a narrow pulse in the time domain corresponding to each transmitted data symbol. Selection of the frequency separation and phases of the carriers controls the timing of the pulses. Equivalently, pulse waveforms may be generated from an appropriate selection of polyphase sub-carrier codes. Time division of the pulses and frequency division of the carriers may be employed for multiple access. Received signals are processed by combining frequency-domain components corresponding to a desired user's allocated carriers. Individual data symbols are processed by providing polyphase decoding, matched filtering, or time-domain shifting the received carriers. Carrier Interferometry components may be used to build various signals corresponding to other transmission protocols.

Apparatuses, systems, and methods are disclosed that provide for an agile coherent optical modem that can generate agile RF waveforms and data rates on a generic opto-electronic hardware platform. An “agile coherent optical modem” [ACOM] approach to optical communications by employing a software configurable and adaptive technologies to the transport system. The ACOM generate agile RF waveforms and data rates on a generic opto-electronic hardware platform. By employing advanced communication techniques to the optical domain such as wavelength agility, waveform agility, and symbol rate agility, it is possible to enable robust optical communications. The ACOM allows for the transport capacity of a communications link to be varied, thereby accommodating variations in transport conditions, range, opacity, etc.

In optical filter systems and optical transmission systems, an optical filter compresses data into and / or derives data from a light signal. The filter way weight an incident light signal by wavelength over a predetermined wavelength range according to a predetermined function so that the filter performs the dot product of the light signal and the function.

An optical transceiver for converting and coupling an information-containing electrical signal with an optical including a housing having an electrical connector with a plurality of XFI electrical interfaces for coupling with an external electrical cable or information system device and for transmitting and / or receiving an information-containing electrical signal having a data rate ate least 10 Gigabits per second on each interface, and a fiber optic connector adapted for coupling with an external optical fiber for transmitting and / or receiving an optical communications signal having a data rate at least 40 Gigabits per second; and at least one electro-optical subassembly in the housing for converting between and information-containing electrical signal and a modulated optical signal corresponding to the electrical signals.

Disclosed is a wireless communication system using visible light and, more particularly, a short-range wireless communication system using a camera sensor module and a flash module mounted on a wireless terminal. The wireless terminal utilizes an LED and a camera sensor selectively for performing camera functions in a wireless terminal and as interface modules for visible light short-range communication.

An optical communications network includes a terminal which can simultaneously receive and modulate an optical signal. The terminal includes an optical modulator which is controlled by varying the bias voltage applied to it.

High-impedance optical electrodes modulate light in response to a life-form bio-potential and then converts the modulated light to an electrical signal that provides traditional EEG and EEC type output. Light splitters are used to provide multiple electrodes and an electronic reference source. A pilot tone is used to achieve high sensitivity and synchronize multiple units while an optical phase-shift modulator is used to reduce optical noise.

A phase shift unit provides a prescribed phase difference (π / 2, for example) between a pair of optical signals transmitted via a pair of arms constituting a data modulation unit. A low-frequency signal f0 is superimposed on one of the optical signals. A signal of which phase is shifted by π / 2 from the low-frequency signal f0 is superimposed on the other optical signal. A pair of the optical signals is coupled, and a part of which is converted into an electrical signal by a photodiode. 2f0 component contained in the electrical signal is extracted. Bias voltage provided to the phase shift unit is controlled by feedback control so that the 2f0 component becomes the minimum.

Improved method and apparatus for hand-held portable LED illumination. The illumination source includes a plurality of LEDs, and an electrical circuit that selectively applies power from the DC voltage source to the LED units, wherein the illumination source is suitable for handheld portable operation. In some embodiments, the electrical circuit further includes a control circuit for changing a proportion of light output having the first characteristic color spectrum output to that having the second characteristic color spectrum output, and that drives the LEDs with electrical pulses at a frequency high enough that light produced has an appearance to a human user of being continuous rather than pulsed. Still another aspect provides an illumination source including a housing including one or more LEDs; and a control circuit that selectively applies power from a source of electric power to the LEDs, thus controlling a light output color spectrum of the LEDs.

There is provided a visible light control apparatus including: a modulation unit (corresponding to a PPM signal generation circuit, a subcarrier generation circuit, and a first AND circuit) that modulates a subcarrier and thereby generates a modulated signal; a visible light control unit (corresponding to a driving circuit) that controls blinking of visible light which contains information based on the modulated signal modulated by the modulation unit and allows the visible light to be emitted at a predetermined emission time ratio; and an emission time ratio control unit (corresponding to a dimming signal generation circuit, an inverting circuit, a second AND circuit, and an OR circuit) that changes the predetermined emission time ratio and allows the visible light to be emitted at the changed emission time ratio.

For an information terminal to be operated by users for collecting predetermined pieces of information from remote information devices by free-space optical communication, the present invention provides a technique for suppressing the power consumption of the information terminal by minimizing the amount of calculation performed to collect the aforementioned information. According to the present invention, each information device emits ID light on which a low-frequency pilot signal is superimposed. The information terminal captures a series of frames of images including the ID light and locates the ID light within the images by the following steps: (1) creating multiple levels of binned images having different resolutions for each frame of the image; (2) calculating an evaluation index for each pixel within a target range of the binned images at each level, from the lowest to the highest resolution, where the target range is narrowed every time the process switches over to a lower level. In (2), the evaluation index is calculated by an evaluation function including fast Fourier transformation performed throughout the series of frames of images. The evaluation index thus calculated is compared with a threshold to determine whether the pixel concerned is receiving ID light. The present technique significantly reduces the number of pixel to be analyzed and evaluated, thereby decreasing the total number of arithmetic operations to be performed using the evaluation function. Thus, the power consumption is suppressed.

An information reception device comprising an imaging portion; a light reception portion for light reception of optional information subjected to optical modulation; a specification portion for specifying an optical modulation region contained in a capture angle of the imaging portion; a decoding portion for controlling the light reception portion in order to carry out light reception of the optical modulation region specified by the specification portion and decoding the optional information from the optical modulation content contained in the region; and a reproduction portion for reproducing the optional information decoded by the decoding portion. By acquiring a region essential for detection of optical modulation, acceleration of the information decoding process is achieved. Furthermore, position adjustment of the optical modulation region is easily accomplished.

An optical transmitter for generating a modulated optical signal for transmission over dispersive fiber optic links in which a broadband analog radio frequency signal input is applied to a modulation circuit for directly modulating a semiconductor laser with the analog signal input. The transmitter may further include a temperature sensor in proximity to the laser and a negative feedback control circuit coupled to the temperature sensor for adjusting the temperature of the laser in response to an output characteristic of the laser, such as linearity.

A system and method for quantum key delivery in a single-photon, free-space cryptography scheme including a transmitter and a receiver. The transmitter includes two pairs of photon sources, each of which represents a specific photon polarization direction. The first pair of photon sources represents a first polarization basis while the remaining pair of photon sources represents a second polarization basis. The first and second polarization basis are rotated with respect to each other so as to produce non-orthogonal polarization eigenstates. A transmitter polarizing beamsplitter corresponding to each of the pairs of the photon sources is provided whereby the polarizations of each of the photon sources of each pair of photon sources are recombined. A transmitter non-polarizing beamsplitter is provided whereby the recombined polarizations are combined for output to the receiver. The receiver includes a set of optics inversely disposed with respect to the optics of the transmitter and two pairs of photon detectors.