1019 results about "Carrier modulation" patented technology

The invention in the simplest form is a self-booting software defined radio (SDR) module which may be embodied as a PCMCIA, Compact Flash, or other plug in form factor module. The performance characteristics of the module, may include the radio frequency (RF) carrier frequency, instantaneous RF bandwidth, carrier modulation and demodulation, symbol coding and decoding, security, and network protocol that can be altered and saved by means of computer software transferred to the module from a host device such as a cellular telephone, personal digital assistant, lap top computer or other programming device

A local area network connected to an infrastructure access device that provides the home LAN with access to voice, data and television services. The infrastructure access device includes a gateway to voice over Internet Protocol services, an interface to a data network for data access, a router to multiplex signals from the gateways and the data network and a Digital Subscriber Line (DSL) transceiver connected to a gateway device in the customer premises. The gateway device includes a DSL transceiver to communicate over the DSL connecting it to the infrastructure access device to provide the home LAN with high performance communications services without the use of POTS. The DSL transceiver may communicate using a switched carrier modulation scheme to conserve power and reduce crosstalk.

A signal processing system which discriminates between voice signals and data signals modulated by a voiceband carrier. The signal processing system includes a voice exchange, a data exchange and a call discriminator. The voice exchange is capable of exchanging voice signals between a circuit switched network and a packet based network. The signal processing system also includes a data exchange capable of exchanging data signals modulated by a voiceband carrier on the circuit switched network with unmodulated data signal packets on the packet based network. The data exchange is performed by demodulating data signals from the circuit switched network for transmission on the packet based network, and re-modulating data signal packets from the packet based network for transmission on the circuit switched network. The call discriminator is used to selectively enable the voice exchange and data exchange.

A system for and method of generating electromagnetic radiation in which the radiation has both a first and second utility. The electromagnetic radiation is modulated to produce electronically detectable variations to achieve the second utility, the variations not affecting the first utility. In one embodiment, the electromagnetic radiation is visible light. In this embodiment, the first utility is illumination and the second utility is the transmission of data. In another embodiment, the invention provides a lamp for generating visible light capable of providing illumination and transmitting data to a receiver. Any variations in the visible light resulting from the data transmission are imperceptible by a human eye regardless of the nature of the data being transmitted. In yet another embodiment, a power line carrier modem or wireless network may be used with the present invention to transmit information to the source.

A sinusoidal R.F. carrier is modulated for the transmission of digital binary datastreams through the deletion of carrier wavelets. These wavelets are defined between zero crossover positions representing zero energy locations. One or more wavelets are switched out of the carrier at the zero crossing positions to avoid sideband generation occasioned by electromagnetic energy disturbance. Transmissional amplification as well as receptional amplification is carried out with non-resonating amplifier architecture.

Methods, and apparatus for carrying out the methods, are disclosed for synchronizing a plurality of RF transmitters that are supplied with a common digital information signal for carrier modulation and subsequent transmission on a common channel throughout a prescribed region, whereby the digital signal receivers within the region may receive transmissions on the channel from more than one transmitter. The method involves inserting reference signals into the data sent to the transmitters in order to place them into known states at specific times relative to the digital signals sent to them for transmission. As a result of this method, the digital signals transmitted by each of the transmitters will be identical to one another so that the receivers will be able to identify one received signal as the main signal and the others as echoes. If necessary, the signal transmitted by at least one of the synchronized transmitters may be delayed, such that identical digital signals received from at least two of the transmitters by receivers in the region will arrive at each receiver within a prescribed time window. The methods and apparatus also can be applied to one or a plurality of RF transmitters for purposes of synchronizing processes at the source of the signals and at the transmitters.

A coal-mining machine uses a ground-penetrating radar based on a software-definable transmitter for launching pairs of widely separated and coherent continuous waves. Each pair is separated by a constant or variable different amount double-sideband suppressed carrier modulation such as 10 MHz, 20 MHz, and 30 MHz. Processing suppresses the larger first interface reflection and emphasizes the smaller second, third, etc. reflections. Processing determines the electrical parameter of the natural medium adjacent to the antenna. Deep reflections at 90-degrees and 270-degrees create maximum reflection and will be illuminated with modulation signal peaks. Quadrature detection, mixing, and down-conversion result in 0-degree and 180-degree reflections effectively dropping out in demodulation.

A ground-penetrating radar comprises a software-definable transmitter for launching pairs of widely separated and coherent continuous waves. Each pair is separated by a constant or variable different amount double-sideband suppressed carrier modulation such as 10 MHz, 20 MHz, and 30 MHz Processing suppresses the larger first interface reflection and emphasizes the smaller second, third, etc. reflections. Processing determines the electrical parameter of the natural medium adjacent to the antenna.The modulation process may be the variable or constant frequency difference between pairs of frequencies. If a variable frequency is used in modulation, pairs of tunable resonant microstrip patch antennas (resonant microstrip patch antenna) can be used in the antenna design. If a constant frequency difference is used in the software-defined transceiver, a wide-bandwidth antenna design is used featuring a swept or stepped-frequency continuous-wave (SFCW) radar design.The received modulation signal has a phase range that starts at 0-degrees at the transmitter antenna, which is near the first interface surface. After coherent demodulation, the first reflection is suppressed. The pair of antennas may increase suppression. Then the modulation signal phase is changed by 90-degrees and the first interface signal is measured to determine the in situ electrical parameters of the natural medium.Deep reflections at 90-degrees and 270-degrees create maximum reflection and will be illuminated with modulation signal peaks. Quadrature detection, mixing, and down-conversion result in 0-degree and 180-degree reflections effectively dropping out in demodulation.

A coherent adaptive subcarrier modulation system applies subcarrier modulation to quadrature modulated signals with constant envelope modulation suitable for efficient sinewave and squarewave subcarrier modulations. The quadrature subcarrier enables the addition of new signals to the in-phase and quadrature phase signals with spectral isolation in the Global Position System while maintaining a constant envelop amplitude.

For each small image region (in space and time), a measure of perceptual transparence of each of a set of possible watermark carrier modulations is used to choose a subset of such modulations, from which a secure random number generator selects, for each image region, a single carrier, modulations of which carry the watermark data.

A method of modulating an optical carrier. A target carrier modulation is computed based on an input data signal. An effective length of an optical modulator is then controlled based on the target carrier modulation.

A method is provided for determining a control scheme for a neutral point clamped (NPC) voltage source converter (VSC) with at least 3 levels and a topology of three bridge legs between each of three phases of a grid and a neutral point. Each leg includes at least four active switches, and a clamping carrier modulator synchronized with the grid is provided for the control of no-switching intervals. The method includes: analyzing the waveform of the grid and / or a load voltage and determining windows defining an allowed period for no-switching of the corresponding bridge leg; operating or simulating the operation of the voltage source converter with different clamping carrier modulator frequencies, and then analyzing the balance in the operating junction temperatures and / or power losses across the active switches and also analyzing the total losses of the voltage source converter; comparing the balance and the total losses of different clamping carrier modulator frequencies and selecting either the clamping carrier modulator frequency according to showing, as primary criterion, the better balance and, as secondary criterion, the lower total losses; operating or simulating the operation of the voltage source converter with the selected clamping carrier modulator frequency, while iteratively changing at least one of the following operating parameters of the voltage source converter: switching frequency, DC-link voltage reference, duty cycle of clamping carrier modulator, phase shift of the clamping carrier modulator relative to the grid, and optimizing the balance in the operating junction temperatures and / or power losses across the active switches and the total losses of the voltage source converter as a function of the adjustment of these operating parameters until reaching optimum operation parameters for the control scheme.

Transmission of baseband and carrier-modulated vector codewords, using a plurality of encoders, each encoder configured to receive information bits and to generate a set of baseband-encoded symbols representing a vector codeword; one or more modulation circuits, each modulation circuit configured to operate on a corresponding set of baseband-encoded symbols, and using a respective unique carrier frequency, to generate a set of carrier-modulated encoded symbols; and, a summation circuit configured to generate a set of wire-specific outputs, each wire-specific output representing a sum of respective symbols of the carrier-modulated encoded symbols and at least one set of baseband-encoded symbols.

The invention relates to a precise tracking and measuring method of a high dynamic signal of an air fleet link, belonging to the technical field of aeronautical data links and radio navigation, and aiming at providing a precise tracking and measuring method of the high dynamic signal the an air fleet link and an implementation structure to solve the problems in the prior art. The invention provides a system framework of the precise tracking and measuring method of the high dynamic signal of the air fleet link, which can be implemented on a digital signal processor (DSP) and a FPGA (field programmable gate array) of a circuit board, and overcomes the defects of the unfavorable precision of a traditional high dynamic receiver by utilizing a double-loop structure of a frequency tracking loop of carrier tracking and a phase locking loop as well as a code phase locking loop to realize the high precise tracking under a high dynamic condition. The method can be widely applied to satellite navigation receivers, range measurement systems and communication systems based on a quiescent carrier modulation direct sequence spread spectrum system.

Multi-band single-carrier modulation. A novel approach is presented by which interference compensation may be performed for signals received by a piconet operable device. The piconet operable device may be implemented within a region that includes two or more SOPs (Simultaneously Operating Piconets). Estimation of the level and location of interference is performed and the input to a decoder (within the piconet operable device) is selectively weighted to ensure that the effect of any existent interference within the signal received by the piconet operable device is minimized. Different interference levels are dealt with differently. For one example, portions of the received signal having undergone a large amount of interference may be simply treated as erasures with respect to the input the decoder. For another example, portions of the received signal having undergone some smaller degree of interference, but some interference nonetheless, may be de-weighted before being provided to the decoder.

An object is to generate a pilot signal for estimating transmission characteristic of a transmission channel which is suitable for the OFDM / OQAM multicarrier modulation. A phase reference pilot symbol of which a modulation amplitude is suppressed to zero, and an amplitude reference pilot signal obtained through modulation performed by using an amplitude known to a reception end are transmitted from a transmission end, and the transmission characteristic of the transmission channel is estimated and compensated by using the phase reference pilot signal and the amplitude reference pilot signal at the reception end. Thus, it is possible to simplify frame generation process performed at the transmission end, and reduce transmission power for the phase reference pilot signal.

For one aspect of the invention, a method is described for mitigating power spectral density irregularities in a multi-carrier modulation environment. The method involves identifying at least one carrier of a plurality of carriers that is in a non-data bearing state. Thereafter, that carrier is modulated with random data.

The invention provides a method for reducing peak-to-average power ratio of a filter bank multi-carrier system, and relates to the field of multi-carrier modulation method. The method comprises the following steps: the analysis of main factors affecting the peak-average power ratio of the FBMC system through the establishment of the FBMC system model and the definition of the peak-average power ratio of the FBMC system, the construction of an FSLM method and the check analysis of Monte Carlo simulation experiments, and is characterized in that: a frame selection mapping method is called as the FSLM method, is a signal non-distortion technique, selects sequences for FBMC signal frames and design frames, constructs FBMC carrier frame signals which have the same information and are independent from one another according to the frame selection sequences, and then selects a frame of symbols allowing the time domain signals to have minimum PAPR, and the method can reduce the PAPR of the FBMC system without distortion, and effectively reduce the PAPR of the FBMC system. The invention can ensure that the requirements of the low peak-to-average power ratio of the system, and further optimize the performance of the system. In practice, the invention can provide certain reference value for the application of Beyond3G, 4G, 802.16 and other communications systems.

An improved multicarrier modulation system and method, which has the advantages of both isotropic orthogonal transfer algorithm orthogonal frequency division multiplexing (IOTA OFDM) and scalable advanced modulation (SAM), is introduced. The invention is root raised cosine (RRC) OFDM using the most spectrally efficient RRC filter without sacrificing the compact subchannel spacing of OFDM. The invention further provides an adjacent channel interference (ACI) suppression scheme and a modified RRC for better suppressing ACI of RRC OFDM. The ACI suppression scheme can also be applied to SAM with the modified RRC and to IOTA OFDM with a modified IOTA. The invention greatly improves a major problem of conventional OFDM namely ACI due to the use of a wide subchannel filter. Thus, the invention allows OFDM to meet even the strictest ACI requirements, which was not possible by using a conventional raised cosine windowing method.

A method is provided for optimizing the design parameters of a RFID tag for use with a RFID reader in a RFID system. In the method, a desired frequency band that the RFID tag will operate in is chosen. Additionally, a maximum acceptable cost for the RFID tag, a minimum acceptable data range for the RFID tag and a minimum operating voltage for the RFID tag are chosen. For a given cost, an optimal data rate is calculated by varying a carrier modulation period of an interrogation signal generated by the RFID reader and antenna capacitance of the RFID tag. Next, an optimal range for a given operating voltage is calculated using the optimal data rate.

The invention relates to a generation and capture system of an encrypted frame hopping spread spectrum signal of an air fleet link, belonging to the technical field of aeronautical data link and radio navigation. The invention discloses a system framework of an encrypted frame hopping spread spectrum signal generation and capture method which can be implemented on a digital signal processor (DSP)and a FPGA (field programmable gate array) of a circuit board, and provides a baseband signal generation algorithm of an encrypted frame hopping spread spectrum system to replace a traditional long periodic sequence spread spectrum code and a compound pseudo code by absorbing the advantages of the easy capture of the compound pseudo code and the difficult breaking of the long periodic sequence spread spectrum code; and meanwhile, the invention provides two advanced and high-performance encrypted frame hopping spread spectrum signal capture algorithms, i.e. a frequency domain parallel capture method of the encrypted frame hopping spread spectrum signal of based on a FFT (fast fourier transform algorithm) and a direct capture method of the encrypted frame hopping spread spectrum signal based on a matching filter and the FFT. The invention solves the problem of difficult capture of the traditional long periodic sequence spread spectrum code. The method can be widely applied to satellite navigation receivers, range measurement systems and communication systems based on a quiescent carrier modulation direct sequence spread spectrum system.

The invention discloses a vehicle network integration technology-based electric vehicle charging system and an implementation method thereof. The electric vehicle charging system comprises an electric vehicle network mobile computing terminal, which establishes a connection with an intelligent electric network via a power line carrier modulation and demodulation module, is connected with a cloud computing remote service platform, and uploads vehicle information of electric vehicles to the cloud computing remote service platform; the cloud computing remote service platform transmits charging information to positioning practicable charging station information and the electric vehicle network mobile computing terminal; electric vehicles are in information interaction via vehicle-mounted electric vehicle mobile computing terminals; and a microwave power transmission device is arranged in a charging station. The implementation of the invention is based on an electric vehicle technology integrating a vehicle intranet and a vehicle outer net; the vehicle intranet is large in information transmission capacity, is communicated with transport facilities via the wireless communication manner of a power line carrier; and the real-time performance of communication on the premises of multiple networks and larger data capacity is ensured.

A communication device converts a bit stream to multiple symbols and provides encryption at a physical layer by shifting a phase of each symbol of the multiple symbols to produce multiple encrypted symbols. Each encrypted symbol of the multiple encrypted symbols is modulated with an orthogonal subcarrier to produce at least one modulated subcarrier and the at least one modulated subcarrier is then transmitted via a wireless link. On a receive side, a receiving communication device receives the transmitted, encrypted symbols and provides decryption at a physical layer by shifting a phase of each encrypted symbol in correspondence with the phase used to encrypt the symbol at the transmit side.

Disclosed is a visible ray communication system including a transmission apparatus and a reception apparatus, wherein the transmission apparatus includes: a plurality of light emitting devices; an S / P converter for serial-to-parallel converting transmission data, thereby generating N data streams; a modulator for modulating the generated N data streams for respective carriers with a predetermined number of dimensions, thereby generating N modulated signals; a carrier signal multiplier for multiplying the generated N modulated signals by orthogonal N carrier signals, respectively, thereby generating N transmission signals; and a light emitting control unit for illuminating the plurality of light emitting devices according to the generated N transmission signals.

The invention provides an optical fiber acceleration transducer probe and an optical fiber acceleration transducer system based on the phase generated carrier modulation technique. The system comprises a laser light source, optical fibers, a fiber coupler, the optical fiber acceleration transducer probe, a photoelectric detector and an electric demodulating system of phase generated carrier modulating signals, wherein the laser light source is a phase generated carrier modulated laser light source; the fiber coupler is respectively connected with the laser light source, the acceleration transducer probe and the photoelectric detector through the optical fibers; the photoelectric detector is connected with the electric demodulating system of the phase generated carrier modulating signals through wires or cables; and the optical fiber acceleration transducer probe comprises an acceleration detecting structure, at least one back plate, an acceleration transducer frame and at least one fiber sensor head. By adopting a double back plate structure and a fiber reading and detecting method, the system of the invention is improved and enhanced in the aspects of shock resistance and overload resistance performances, anti-electromagnetic interference, sensitivity and the like.