47 results about "Dual carrier modulation" patented technology

The present invention provides a versatile system for selectively spreading carrier data across multiple carrier paths within an Orthogonal Frequency Division Multiplexing (OFDM) system (200), particularly an ultra-wideband (UWB) system. The present invention provides a data input (202), which passes data to a randomizer (204). The data then passes to a convolutional code function (206), the output of which is punctured by puncturing function (208). An interleaver function (210) receives the punctured code data, and cooperatively operates with a mapper element (218) to prepare the coded data for pre-transmission conversion by an IFFT (220). The mapper element (218) comprises a dual carrier modulation function (216), which associates and transforms two punctured code data elements into a format for transmission on two separate signal tones.

A method of demodulating a modified dual carrier modulation (MDCM) signal using hard decision includes generating real symbol vector candidates and imaginary symbol vector candidates which correspond to an MDCM signal pair; calculating a first norm between a real part of the MDCM signal pair and each of the real symbol vector candidates and determining as a real symbol vector a real symbol vector candidate that has the minimum first norm among the real symbol vector candidates; and calculating a second norm between an imaginary part of the MDCM signal pair and each of the imaginary symbol vector candidates and determining as an imaginary symbol vector an imaginary symbol vector candidate that has the minimum second norm among the imaginary symbol vector candidates.

A dual carrier modulator that modulates an orthogonal frequency division multiplexing (OFDM) carrier, includes an input part receiving a predetermined number of coded bits; a memory part storing the coded bits received through the input part; a detection part detecting four bits among the coded bits in a predetermined order; and an operation part generating a modulated symbol comprising a real part and an imaginary part, using the four detected bits and a predetermined unitary matrix. Here, one of the detected four bits is included in a real part of a first modulated symbol and in an imaginary part of a second modulated symbol. Accordingly, loss of signals caused by mismatching between an In-phase channel and a Quadrature channel can be prevented.

The invention discloses an inverter parallel-connection loop current restraining system based on PR control and dual-carrier modulation. By means of the inverter parallel-connection mode, the power capacity of an inverter system is increased. Meanwhile, a proportion resonance control device is adopted in an inverter, and therefore low-frequency zero-sequence loop currents can be effectively restrained; the dual-carrier modulation method is used, a zero vector is replaced by a non-zero vector so that the high-frequency zero-sequence loop currents can be restrained. The restraining system has the advantages of being high in direct-current voltage utilization rate and small in zero-sequence loop current.

A coding unit for determining two different types of modulation to be applied to two carrier signals such that each modulated carrier signal represents a data symbol in accordance with a group of modulation points, each modulation point representing a modulation of the first type and a modulation of the second type that can be applied to one of the carrier signals, the coding unit being arranged to associate the data symbol with a first one of the modulation points by applying a first mapping function to that data symbol and associate the data symbol with a second one of the modulation points by applying a second mapping function to that data symbol, the first and second mapping functions being such that they each map two different data symbols to a respective common modulation point; and determine the modulation of the first and second types to be applied to the first carrier signal to be the modulation of the first and second types represented by the first modulation point and the modulation of the first and second types to be applied to the second carrier signal to be the modulation of the first and second types represented by the second modulation point.

A dual carrier modulation (DCM) demapping method and a DCM demapper using the method are provided. The DCM demapping method includes: receiving DCM constellation sets; respectively calculating a one-dimensional log likelihood ratio (LLR) for each bit of each constellation set; and diversity combining the calculated one-dimensional LLR to calculate an output of an LLR.

The invention discloses a device and a method for estimating delay, frequency and phase of a passive intermodulation signal, belonging to the technical field of signal processing of wireless communication, satellite communication and ground communication systems. According to the method, orthogonality down-conversion, low pass filtering and sampling are separately performed on a dual carrier modulating signal so as to obtain corresponding baseband signals; then, a passive intermodulation (PIM) center frequency falling into a reception band is computed, and orthogonality down-conversion and sampling are performed according to the PIM center frequency so as to obtain corresponding baseband signals; an n-order PIM baseband signal with the center frequency of Omega c is computed; operation is performed on the obtained baseband signals and the PIM baseband signal so as to obtain four paths of correlation values; squaring and summing are performed on the four paths of correlation values, and a peak position is searched by use of two dimensions of delay and frequency so as to obtain delay and frequency offset; and after the delay and frequency offset are compensated, correlation values are recomputed, and finally, the phase is computed. The method is simple, has low complexity and good real-time performance, and can realize good estimation performance under high noise condition.

The present invention discloses a method for processing IQ data of radio-frequency remote unit (RRU), the method comprising: after receiving IQ data sent by a baseband processing unit (BBU) via a dual carrier, the RRU conducts parallel processing on IQ data on the dual carrier, modulates the processed dual carrier into a radio-frequency signal and outputs the signal to an antenna terminal. The present invention discloses an IQ data processing system and a radio-frequency remote unit at the same time. The technical solution of the present invention enhances the capability of an active antenna for transmitting data and reduces cost.

A DCM demapper and a DCM demapping method are provided. The DCM demapper includes: a basic signal generation unit generating a plurality of basic signals using a signal and channel information of two subcarriers; a soft decision generation unit generating a plurality of soft decisions using the plurality of basic signals; and a soft decision selection unit selecting a soft decision corresponding to each bit of the two subcarriers among the generated soft decisions.

Disclosed herein is a demapping device and method for a Modified Dual Carrier Modulation (MDCM) system. The demapping device comprises: the received signal processing unit receives an MDCM signal preprocessed by an operation preparation unit, and calculates differences between squares of distances between the received signal and a plurality of constellation points; the index search unit searches for a constellation point closest to the received signal based on the differences between squares of distances between the received signal and each of a plurality of constellation points; and the demapping operation unit searches for constellation points close to the closest constellation point, and sends demapping result data to a decoding device. The demapping result is obtained by demapping based on differences between squares of distances between the closest constellation point and the close constellation points.

The embodiment of the invention provides a data transmission method, device and system based on dual-carrier modulation (DCM). In the embodiment of the invention, when binary convolutional coding is adopted and the transmission code rate is greater than a half, first data obtained by binary convolutional coding is punched by adoption of different punching modes, namely a first punching mode and a second punching mode; missed bits of the first punching mode and the second punching mode on two same data are different; but, the transmission code rates of obtained punched data, namely first punched data and second punched data, are same; therefore, a receiving end can obtain the missed bits of another data from one data; the coding gain is obtained; furthermore, compared with the existing DCM technology, the data transmission bit error rate based on DCM can be reduced; and the data transmission reliability can be increased.

The invention discloses a double-carrier-wave modulation method of a modular multilevel converter. The method comprises two parts, i.e., double-carrier-wave modulation and a voltage balance control method. First of all, according to reference voltages of upper legs and lower legs, quantities of submodules needing to be invested for the upper legs and the lower legs are respectively obtained through the double-carrier-wave modulation, a submodule change quantity needing to be invested at a current control period is further obtained, and then capacitance voltage balance is realized through the capacitance voltage balance control method. An operation condition is determined according to an absolute value of the invested submodule change quantity, only submodules needing switching operation or removal are calculated, the computation complexity is further reduced on the basis that a switch frequency is reduced, and the performance of a control system is improved. The method provided by the invention has the advantages of easy realization, good harmonic wave characteristics, low switch loss and the like.

The invention discloses a Vienna rectifier midpoint potential low-frequency oscillation suppression modulation method, which comprises the following steps of: firstly, providing a novel simplified algorithm to obtain action time of each basic vector based on equivalent space vector modulation realized by dual carriers; and then, by adding a neutral-point potential balance compensation factor into a zero-sequence component of dual-carrier modulation, on the basis of realizing neutral-point potential balance by adjusting action time of positive and negative redundant small vectors, investigating a middle vector and a non-redundant small vector, analyzing the influence of the middle vector and the non-redundant small vector on the neutral-point potential, optimizing the neutral-point potential balance compensation factor, and middle-point potential low-frequency oscillation caused by the middle vector and the non-redundant small vector is suppressed. The midpoint potential low-frequency oscillation suppression modulation method is provided for the Vienna rectifier, the problem of midpoint potential low-frequency oscillation is effectively solved, and the system stability is improved.

Labeling diversity of the superposition coding modulation (SCM) of dual-carrier modulation (DCM) of a coded orthogonal frequency-division multiplexed (COFDM) signal is used to reduce its peak-to-average-power ratio (PAPR). The reduction of data throughput owing to DCM is compensated for by quadrupling the number of lattice points in SCM mappings of the quadrature amplitude modulation (QAM) of the carriers of the COFDM signal. The labeling diversity can be such as to minimize PAPR or such as to reduce PAPR less, but improve signal-to-noise (SNR) for reception of the COFDM signal transmitted via an additive-white-Gaussian-noise (AWGN) channel.

The invention discloses a non-isolated H bridge bidirectional DC-DC converter modulation strategy based on dual carrier modulation, which includes the following steps: a DC bus voltage V<DC> is measured by a voltage sensor and compared with a given value V<ref> to obtain a difference; the obtained difference passes through a voltage loop PI module as a current reference value I<ref>; the current reference value I<ref> is compared with the inductor current I<l> measured by a current sensor to obtain a difference; the obtained difference passes through a current loop PI module and modulated by a double triangular carrier signal to obtain a required PWM wave; the PWM wave is used as a switch tube pulse driving signal to control on-off of a switch tube and to make the switch tube work in a continuous duty cycle state. In the invention, while the mode of an H bridge bidirectional DC-DC converter is switched, the duty cycle of the switch tube can be changed from an intermittent state to a continuous state, the control process is simplified, and when the mode of a switch is switched, the voltage overshoot becomes smaller and the adjustment time becomes shorter.

The invention provides an isolated driving signal transmission circuit which comprises an input signal receiving module which is coupled between a first power supply and a first ground end and is usedfor receiving an input signal, carrying out dual-carrier modulation processing on the input signal and outputting a differential signal, and an output module which is coupled between the first powersupply and a second ground end and is used for outputting a differential signal; a high-voltage capacitor serving as an isolation medium and being coupled with the input signal receiving module to receive the differential signal; and an output signal providing module coupled between a second power supply and a second ground end, coupled with the high-voltage capacitor at the same time, used for receiving the differential signal through the high-voltage capacitor, and providing an output signal after carrying out dual-carrier demodulation processing on the differential signal.

The invention discloses a low-frequency harmonic suppression modulation method of a high-switching-frequency silicon carbide inverter. A main circuit is connected with a dual-carrier modulation modulefor suppressing low-frequency harmonic waves and a current polarity extraction module; a three-phase output current in the main circuit is inputted to the current polarity extraction module, and a three-phase fundamental wave current is obtained; the three-phase fundamental wave current and a three-phase modulation wave are input into a double-carrier modulation module for suppressing low-frequency harmonic waves, and the module outputs driving signals of six silicon carbide power switching devices to a main circuit, so a control loop of the whole double-carrier modulation method for suppressing the low-frequency harmonic waves of the high-switching-frequency silicon carbide inverter is formed. A driving signal is obtained by comparing double carriers with a modulation wave; a driving vacant region is added between upper and lower tube driving signals, a dead zone is obtained without additionally adding a switch-on delay link, a control loop does not have a delay link caused by switch-on delay, the current polarity extraction module is added, the amplitude of double carriers is changed according to the current polarity, and the purpose of suppressing low-frequency harmonic waves of the high-switching-frequency silicon carbide inverter is achieved.