97 results about "Residual carrier" patented technology

Disclosed is a unique system and method for recognizing the type of modulation embedded in an unknown complex baseband signal, comprising a receiver section for extracting the complex baseband signal from a modulated signal having a carrier frequency, and comprising an orderly series of signal processing functions for (a) estimating the bandwidth of the unknown signal, (b) removing the out-of-band noise and correcting gross carrier frequency errors, (c) discriminating between constant envelope and irregular envelope signals, (d) estimating and correcting residual carrier frequency errors, (e) classifying a constant envelope signal into one of the following modulation formats: {Continuous Wave (CW), Frequency Modulation (FM), Frequency Shift Keying (FSK)}, and (f) classifying an irregular envelope signal into one of the following modulation formats: {Amplitude Modulation (AM), Double Sideband Suppressed Carrier (DSB-SC), Binary Shift Keying (BPSK), Quaternary Phase Shift Keying (QPSK), π / 4-shifted QPSK, M-ary PSK (MPSK), and OTHER classes}.

The invention discloses a fully-digital direct sequence spread spectrum communication system and a rapid pseudo code capturing method thereof. A digital signal is processed by using an FPGA (Field Programmable Gate Array) which comprises a pseudo code capturing module, a sampling signal of an ADC (Analog To Digital Converter) is subjected to frequency mixing with a signal of a local carrier NCO (Numerically Controlled Oscillator) and filtered to obtain a baseband signal, residual carrier Doppler frequency is eliminated from the baseband signal by adopting a differential multiplying mode, thus the phase deviation of a receiving signal and a local pseudo code is further obtained through an FFT (Fast Fourier Transform) algorithm without scanning on a carrier frequency domain; and when the phase deviation of the pseudo code is obtained, a local pseudo code phase is modified and is subjected to correlation degree of dissociation with the receiving signal, and the carrier Doppler frequency is figured out by using the FFT algorithm, and is compensated to a carrier NCO and a pseudo code NCO, thus carrier frequency capturing and pseudo code capturing are realized.

Methods and apparatus are provided for processing a set of GNSS signal data derived from signals of a first set of satellites having at least three carriers and signals of a second set of satellites having two carriers. A geometry filter uses a geometry filter combination to obtain an array of geometry-filter ambiguity estimates for the geometry filter combination and associated statistical information. Ionosphere filters use a two-frequency ionospheric combination to obtain an array of ionosphere-filter ambiguity estimates for the two-frequency ionospheric combinations and associated statistical information. Each two-frequency ionospheric combination comprises a geometry-free two-frequency ionospheric residual carrier-phase combination of observations of a first frequency and observations of a second frequency. Auxiliary ionosphere filters use an auxiliary ionospheric combination to obtain an array of auxiliary-ionosphere-filter ambiguity estimates for the auxiliary ionospheric combinations and associated statistical information. Each auxiliary ionospheric combination uses carrier-phase observations of a third frequency and carrier-phase observations of at least one of the first frequency and the second frequency. A combined array of ambiguity estimates is prepared for all carrier phase observations and associated statistical information by combining the arrays of the geometry filter and the ionosphere filters and the auxiliary ionosphere filters.

This invention provides a method and device to correct remaining frequency offset of the carrier wave and to fix phase and amplitude deviation. First, separately compare the channel parameters of each pilot frequency of the sub-carrier wave at the OFDM data symbol and the channel parameters of each pilot frequency of the sub-carrier wave at No. REF2 training symbol to check the changes in the channel parameters of the data symbol of the pilot frequency of the sub-carrier wave compared to that of the REF2 training symbol. Then divide these values into two paths, to seek the average of the virtual part and the real part of one path, to seek the modulus of the other path first and then to seek the average of the modulus. Then the result of the first path divides its own modulus and then multiples the result of the second path, the value of which is finally divided by the value of each sub-carrier wave in the symbol and the compensation is completed. This method is easy to be implemented and can correct a polarity of deviations affecting OFDM data symbol. And as long as the position of the pilot frequency of the symbol is symmetric, the influence on the estimation result caused by sampling clock deviation can be completely offset or compensated, thus has high practical value.

The invention designs an uplink carrier frequency offset estimation and compensation method for a low-earth-orbit satellite multi-carrier communication system, and belongs to the field of wireless communication. The uplink refers to a transmission link which is transmitted by a user terminal, forwarded by a satellite and received by a gateway station. The method specifically comprises the following steps: (1) a user terminal calculates an uplink pre-compensation carrier frequency offset value according to a downlink carrier frequency offset estimation value, and pre-compensates an uplink transmission signal; (2) the gateway station estimates Doppler carrier frequency offset of uplink and downlink feed links based on ephemeris, calculates a feed link carrier frequency offset compensation value, and performs first compensation on uplink received signals; and (3) the gateway station estimates the uplink residual carrier frequency offset by using the uplink synchronization or reference signal, and performs secondary compensation on the uplink received signal. By utilizing the method and the system, the uplink carrier frequency offset can be accurately estimated and compensated under the condition that the user terminal has no ephemeris and only the gateway station has ephemeris, so that the demodulation requirement of multi-carrier communication under the large Doppler carrier frequency offset of a low-earth-orbit satellite is met.

Methods and apparatus are provided for processing a set of GNSS signal data derived from signals of a first set of satellites having at least three carriers and signals of a second set of satellites having two carriers. A geometry filter uses a geometry filter combination to obtain an array of geometry-filter ambiguity estimates for the geometry filter combination and associated statistical information. Ionosphere filters use a two-frequency ionospheric combination to obtain an array of ionosphere-filter ambiguity estimates for the two-frequency ionospheric combinations and associated statistical information. Each two-frequency ionospheric combination comprises a geometry-free two-frequency ionospheric residual carrier-phase combination of observations of a first frequency and observations of a second frequency. Auxiliary ionosphere filters use an auxiliary ionospheric combination to obtain an array of auxiliary-ionosphere-filter ambiguity estimates for the auxiliary ionospheric combinations and associated statistical information. Each auxiliary ionospheric combination uses carrier-phase observations of a third frequency and carrier-phase observations of at least one of the first frequency and the second frequency. A combined array of ambiguity estimates is prepared for all carrier phase observations and associated statistical information by combining the arrays of the geometry filter and the ionosphere filters and the auxiliary ionosphere filters.

The invention provides a method with the QoS requirement for distributing resources in a CR OFDM system, which comprises the following steps: selecting a cognitive user whose gamma m is maximal from a to-be distributed cognitive user set UM, distributing the proper sub-carrier wave, power and bit number for the cognitive user according to the principle that the gain factor gamma mn is larger than the priority or the bit numbers are approximate, newly confirming to-be distributed sub-carrier wave sets SN and UM, newly calculating the interference I generated to the users by the cognitive users, if the I is bigger than the interference threshold value Ith of the authorized users, canceling the sub-carrier wave and the distributing of the power and the bits and finishing the distributing work, if the UM has no to-be distributed cognitive users and the SN still has the to-be distributed sub-carrier wave resources, then distributing the residual carrier waver resources. The method considers the two restraining conditions of the interference threshold and the QoS requirement of the users, thereby further improving the availability ratio of the frequency spectrum and the distributing of the recourses.

The invention provides an in-phase estimation method and a system of the orthogonal frequency division multiplexing (OFDM) technology, wherein the method includes: obtaining the sub-channels which satisfy the given transmission quality in the OFDM symbols; computing the phase offset between the data on the obtained sub-channels and the data on the sub-channels with the same position in the adjacent OFDM symbols; estimating the residual carrier frequency shift and the sampling clock shift of the current OFDM symbols. The method and the system estimates the residual carrier frequency shift and the sampling clock shift through the mutual correlation data on the sub-channels which satisfy the given transmission quality, overcomes the effect of the sub-channel with bad quality to generate the error code, advances the precision of the in-phase estimation to a great extent.

Methods and apparatus are provided for processing a set of GNSS signal data derived from signals of a first set of satellites having at least three carriers and signals of a second set of satellites having two carriers. A geometry filter uses a geometry filter combination to obtain an array of geometry-filter ambiguity estimates for the geometry filter combination and associated statistical information. Ionosphere filters use a two-frequency ionospheric combination to obtain an array of ionosphere-filter ambiguity estimates for the two-frequency ionospheric combinations and associated statistical information. Each two-frequency ionospheric combination comprises a geometry-free two-frequency ionospheric residual carrier-phase combination of observations of a first frequency and observations of a second frequency. Auxiliary ionosphere filters use an auxiliary ionospheric combination to obtain an array of auxiliary-ionosphere-filter ambiguity estimates for the auxiliary ionospheric combinations and associated statistical information. Each auxiliary ionospheric combination uses carrier-phase observations of a third frequency and carrier-phase observations of at least one of the first frequency and the second frequency. A combined array of ambiguity estimates is prepared for all carrier phase observations and associated statistical information by combining the arrays of the geometry filter and the ionosphere filters and the auxiliary ionosphere filters.

In a communication device, the LO leakage and opposite side band signals are measured at an output signal. Input processing signals to a modulator are adjusted in response to the measured values to minimize the LO leakage and maximize side band suppression.

A nanowire-based device and method employ removal of residual carriers. The nanowire-based device includes a semiconductor nanowire having a semiconductor junction, and a residual carrier sink. The residual carrier sink is located at or adjacent to the semiconductor nanowire near the semiconductor junction and employs one or both of enhanced recombination and direct extraction of the residual carriers. The method includes providing a semiconductor nanowire, forming a semiconductor junction within the semiconductor nanowire, forming a residual carrier sink, and removing residual carriers from the semiconductor junction region using the residual carrier sink.

The embodiments of the invention provide a carrier wave frequency deviation estimation method and system. For the situation of emission of multiple unlinks from different emitters, due to existence of multipath carrier wave frequency deviations, one carrier wave frequency deviation is corresponding to one emitter, and under such a condition, it is quite difficult to estimate and correct the carrier wave frequency deviations at a receiving end easily. The reason is that composite time domain signals of the receiving end form a height nonlinear function about the carrier wave frequency deviations. Therefore, in order to reduce the complexity, by using the method and system provided by the embodiments of the invention, the carrier wave frequency deviations can be corrected before OFDM signals are sent for realizing the purpose that the only deviation needing to be corrected at the receiving end is a common residual carrier wave frequency deviation, such that the receiving end can perform unified common residual carrier wave frequency deviation compensation on the received N OFDM signals. Compared to the prior art, the phenomenon does not exist that channel estimation and carrier wave frequency deviation tracking are always affected by interference between carrier waves.

The invention discloses a straw-based drug liquid controlled release agent and a preparation method thereof. The preparation method comprises following steps: agricultural straw is smashed to be powder with a particle size of 10 to 100nm; and the straw powder is uniformly mixed with clay, diatomite, water and beta-cyclodextrin; the mixture is delivered into a pelletizer so as to obtain particles with a particle size of 0.001 to 0.01mm; and the surface of the particles is coated with a layer of organic membrane, and then the particles are dried for 12h at a temperature of 40 to 60 DEG C so as to obtain the finished products of the straw-based drug liquid controlled release agent. When the particulate controlled release agent is immersed in drug liquid such as pesticide, growth promoter and insect repellant, drug molecules will adsorb on the solid particles. After adsorption, if the controlled release agent is sprayed on crops, the controlled release agent will adhere to plant hairs and leaves so as to realize target position fixed effect, and the drug liquid will be released gradually because of the effects of factors such as time, rainwater leaching, and accumulated temperature. The straw-based drug liquid controlled release agent is suitable for slow release of a plurality of pesticides, and is capable of increasing utilization rate of the pesticides greatly, and reducing environment pollution caused by residual carriers.

A method and sytem for achieving carrier frequency synchronization in a high speed receiver. A feedback loop in a carrier recovery system is operated at a down-sampled rate until carrier lock is detected. The output of a phase accumulator, operating at the down-sampled rate, is then extrapolated to provide extrapolated outputs to provide outputs at the original symbol rate. Addresses for a look-up table are then generated from the combined phase accumulator outputs and extrapolated outputs, such that the frequency and phase compensation offsets provided to a phase derotator and slicer are at the original symbol rate. The total pipeline delay as seen by the carrier recovery system is thus reduced. This in turn allows for more efficient correction of residual carrier frequency errors present in a complex baseband signal.

The embodiment of the invention discloses a frequency synchronization method and equipment for an OFDM (Orthogonal Frequency Division Multiplexing) system. In the technical scheme provided by the embodiment of the invention, during frequency synchronization process of the OFDM system, a digital phase-locked loop mechanism is adopted to realize joint estimation of carrier wave frequency deviation and sampling frequency deviation when AD / DA and radio frequency are synchronic, when each frame updates the phase-locked loop state information, only the frequency-domain related characteristics of training symbols are required to be utilized for estimating the residual sampling frequency deviation, and then the residual carrier wave frequency deviation can be obtained through simple calculation, so as to update the frequency deviation estimation. The complexity in system implementation is extremely low, and besides, high estimation precision can be achieved when the digital phase-locked loop is in a locking state.

The invention relates to a wide-range high-precision Doppler measuring method for deep space exploration. An analog PM_BPSK signal of a transmitting end can form a cycle-repeated dual-signal block. Areceiving end converts the received signal into a digital baseband signal. Firstly, FFT calculation is carried out on the digital baseband signal, and a Doppler frequency rough estimation value of thesignal is obtained according to the FFT result. Secondly, according to the obtained rough estimation value, after an original digital baseband signal is subjected to frequency integer correction, andcompensation, a residual carrier signal is obtained through narrow-band filtering, and the residual carrier signal is subjected to conjugate complex correlation fine estimation operation on the basisof the double-signal block to obtain a Doppler fine estimation value. Thirdly, the rough estimation value and the fine estimation value are subjected to fitting to obtain the wide-range high-precision Doppler estimation value. Compared with a traditional Doppler estimation method, the wide-range high-precision Doppler measuring method has the advantages that the measurement efficiency, the measurement range and the measurement precision are all considered, the measurement range is large, the measurement precision is high, the software complexity is low, and the application prospect is wide.

The invention relates to an MIMO-OFDM system frequency deviation estimation method. The method is used for performing frequency deviation estimation on signals which contain a short training sequence, a long training sequence and an SIG sequence and are received by a plurality of receiving antennas of the receiver of an MIMO-OFDM system. The method of the invention includes the following steps that: coarse frequency deviation is calculated through utilizing the short training sequence of the signals; long training sequence frequency deviation is calculated through utilizing the long training sequence of the signals; time-domain residual carrier frequency deviation is calculated through utilizing the SIG sequence; and the coarse frequency deviation, the long training sequence frequency deviation and the time-domain residual carrier frequency deviation are summated, and a summation result is adopted as the estimation result of carrier frequency deviation. The method has the advantages of high frequency deviation estimation accuracy and wide application range.

An image processing device is provided. The image processing device includes a first shift register connected to a line for reading out an image signal that selects a line where a signal in response to carriers accumulated in an accumulation state for generating carriers in the photo diode in response to received light is read out, regarding each line of the matrix by scanning a plurality of lines in a direction that is perpendicular to each line of a matrix and is designated, a second shift register connected to a line for clearing an image signal that selects a line for clearing an image signal where the residual carriers in the solid-state image-pickup element are discharged from the solid-state image-pickup element, and an output circuit that outputs a reset signal to the first shift register when a direction of scanning lines of the matrix is changed.

In a telecommunications transmitter and receiver two IQ-mixers of the same type are operated in 180 degrees phase shift. In both the transmitter and receiver, an input signal is coupled to each IQ-mixer and the output signal of the mixers are combined so as to cancel unwanted error components in each individual output signal. In the transmitter, residual carrier signals are cancelled, and in the receiver, DC-offsets are cancelled. In both, the wanted signals are added, doubling the amplitude of the resultant output signal leading to four times more output power and improved dynamic range.

A system and method for on-orbit calibration of high-gain antenna for deep space exploration are provided. A high-gain antenna in-orbit calibration system for deep space exploration adopts a ground station and a ground station receiving detector, the ground station mainly gives a highly sensitive receiver and a large antenna. The ground station receives the single beacon or the residual carrier radio frequency signal transmitted by the detector, finds out the strongest time of the received signal, and inverts the position of the pointing space through the ground station's receiving detector. The invention carries out antenna on-orbit calibration, eliminates high-gain antenna pointing error to ground in long-term flight of the detector on orbit, and improves the gain value of the communication link.

A channel equalizer includes a channel estimator, a coefficient calculator, a multiplier, and an error remover. The channel estimator estimates a channel impulse response (CIR) of input data in which a known data sequence is periodically inserted. The coefficient calculator calculates equalization coefficients using estimated CIR, and the multiplier multiplies the input data with the equalization coefficients for channel equalization. The error removes estimates a residual carrier phase error of the channel-equalized input data and removes the estimated phase error from the input data.

An image processing device is provided. The image processing device includes a first shift register connected to a line for reading out an image signal that selects a line where a signal in response to carriers accumulated in an accumulation state for generating carriers in the photo diode in response to received light is read out, regarding each line of the matrix by scanning a plurality of lines in a direction that is perpendicular to each line of a matrix and is designated, a second shift register connected to a line for clearing an image signal where the residual carriers in the solid-state image-pickup element are discharged from the solid-state image-pickup element, and an output circuit that outputs a reset signal to the first shift register when a direction of scanning lines of the matrix is changed.

A channel equalizer includes a channel estimator, a coefficient calculator, a multiplier, and an error remover. The channel estimator estimates a channel impulse response (CIR) of input data in which a known data sequence is periodically inserted. The coefficient calculator calculates equalization coefficients using estimated CIR, and the multiplier multiplies the input data with the equalization coefficients for channel equalization. The error removes estimates a residual carrier phase error of the channel-equalized input data and removes the estimated phase error from the input data.

Architecture for processing a record of burst information in a transmission link. A waveform sampler samples a received waveform containing a record of symbols imposed on a carrier signal. Symbol phase of the record symbols is determined utilizing one or more metrics. Any residual carrier error is corrected, and the carrier signal is removed. The phase and time-of-arrival of the burst information associated with a maximum positive correlation value are then determined.

The invention discloses a multi-rate self-adaptive demodulating system aiming at residual carrier modulation. The system mainly aims at a BPSK modulation mode adopting Manchester encoded residual carrier stated in a CCSDS near linkage standard protocol, the information rate can be estimated in the absence of priori information; and the lox-complexity tracking and demodulating can be realized. Through the fine filtering and narrow-band wide-loop tracking, the extracting and tracking on the carrier are realized; the carrier is locked on an I branch and a signal is locked on a Q branch through the tracking of the Costas Loop; the tap extraction on each rate signal is realized; the matching correlation and the energy integral are performed on the Q branch signals on the rate taps according to the characteristics of the Manchester encoding, thereby judging the rate of the current transmission data through the judgment to the energy integral under the condition of unnecessarily knowing the transmission information, and realizing the self-adaptive demodulation.

The invention discloses a residual carrier deviation and sampling deviation estimation method and compensation method of a micro power wireless communication system based on OFDM (Orthogonal Frequency Division Multiplexing) modulation. The estimation method comprises the steps of generating a pilot symbol sequence, conducting symbol mapping, generating time-domain OFDM data symbols, sequentially extracting each OFDM symbol data by a receiving end and accurately conducting residual carrier deviation and sampling deviation estimation and tracking by using the pilot symbol sequence. The compensation method comprises the estimation method and a step of conducting phase compensation on effective data sub-carriers according to the estimated residual carrier deviation and sampling deviation to accurately recover the original transmission data symbols. By adopting a reasonably designed pilot scheme, complex micro power wireless environments can be effectively resisted, accurate estimation of the residual carrier deviation and the sampling deviation is realized, the sub-carriers of the OFDM system is enabled to satisfy the requirement on orthogonality all the time and thus the reliable receiving of OFDM data is effectively assisted.

The invention discloses a non-cooperation BPSK signal decoding method with a polarity judgment operation. The method includes the following steps that (1) a digital medium-frequency channelized receiver detects and receives a BPSK signal; (2) residual carrier frequency of the detected and received BPSK signal is measured roughly; (3) after direct components are filtered out on the basis of square frequency doubling after rough measurement, frequency refining is achieved through CZT frequency measurement, and the residual carrier frequency is calculated; (4) the polarity judgment operation is carried out on the basis that the sequences are combined; (5) code checking is carried out again on the result of the step (4). The method is more suitable for decoding of the BPSK signal in a signal environment with a low signal to noise ratio, the calculation result is more reliable, and calculation complexity is greatly reduced.

An image-processing device is provided. With respect to each line in a matrix, a shift register is installed for reading a line out that selects a line where a signal in response to carriers accumulated in an accumulation state for generating carriers in the photo diode in response to received light is read out. A second shift register is installed that selects a line for clearing an image signal where the residual carriers in the solid-state image-pickup element are discharged from the solid-state image-pickup element. Shift data applied to a line for reading out an image signal is output to the shift register for reading a line out, based on which signal for selecting a line for reading out an image signal is output.