41results about How to "Increase the carrier frequency" patented technology

A pulsed compression noise correlation radar uses noise modulation and pulse compression technology to scramble recognizable transmit signal characteristics and reduce transmit energy. The pulsed noise correlation radar advantageously uses pulse compression technology, a pulsed linear frequency modulated noise correlation mixer, and a new and innovative noise fused waveform to automatically correlate the pulsed linear frequency modulated (LFM) noise waveform with the received signal. The pulsed noise correlation radar apparatus and system now make it possible to effectively reduce transmitting power, preserve high band widths through oversampling in the receiver, and achieve multi-channel array frequency diversity. A secure pulsed compression noise correlation radar system and methods for undetected target detection with pulsed noise correlation radar and a pulsed LFM fused noise waveform are also provided.

The invention creates the field of new energy power generation, and particularly relates to a carrier synchronization method for parallel power generation of many inverters. A carrier frequency of an inverter C1 is same as carrier frequencies of other inverters, the carrier period is shortened, namely, the carrier frequency of the inverter C1 is increased if a carrier output from the inverter C1 lags behind a power grid waveform in a phase, and the carrier period is prolonged, namely, the carrier frequency is slowed if the carrier output from the inverter C1 is ahead of the power grid waveform in the phase. Compared with the prior art, the method has the advantage that carrier synchronization between two inverters can also be achieved without additionally arranging a traditional complicated master-slave control architecture, and circulation between two inverters is improved. The method created by the invention can be implemented by building a functional module and combining a functional module architecture and by a computer program stored in a computer readable storage medium.

The invention relates to an SVPWM (Space Vector Pulse Width Modulation) control method for a Z-source inverter, belongs to the technical field of inverter control and solves the problem of generation of a larger inductive current ripple caused by the existing SVPWM control method for the Z-source inverter. The states of three switching tubes of an upper bridge arm are represented by eight vectors, and the eight vectors divide a control interval into six sectors. For taking the third (III) sector as an example, the vectors taking actions in Ts in each SVPWM period are allocated sequentially from left to right as 111, 110, 100, 000, 000, 100, 110 and 111, wherein the total acting time of a traditional zero vector is set as T0; the total acting time of a direct-through zero vector is set as t0 which is greater than 0 and less than or equal to T0; and the total acting time t0 of the direct-through zero vector is divided into four sections inserted between the acting times of the traditional zero vector and an adjacent effective vector, thereby realizing SVPWM control of the Z-source inverter. The SVPWM control method is suitable for the SVPWM control of the Z-source inverter.

The invention discloses a carrier phase shifted pulse width modulation type digital power amplifier and a power amplification method. The digital power amplifier comprises a digital power amplification controller, a drive circuit module, a power amplification main circuit and a filter module; the digital power amplification controller receives externally input analog audio signals and switching signals to digitalize the analog audio signals and performs PWM (pulse width modulation) on the digitized analog audio signals and 2m digital triangular carriers having a sequential phase difference of Pi/m to generate 2m sets of PWM control signals identical in frequency and proportional to input audio amplitude in terms of duty ratio; the power amplification main circuit is connected with the 2m sets of PWM control signals output by the digital power amplification controller via the drive circuit module so as to amplify and synthesize PWM control signal power, high-power analog audio signals are generated via an LC passive low-pass filter to drive a terminal load. The carrier phase shifted pulse width modulation type digital power amplifier and the power amplification method enables effectively improved output power and reliability of digital power amplification and reduced distortion.

The invention relates to a digital-to-analog converter, in particular to a double-edge triggering high-speed digital-to-analog converter, belonging to the field of integrated circuits. The double-edge triggering high-speed digital-to-analog converter comprises a clock circuit, a data multiplexer, a gating unit and a current helm unit. The clock circuit is used for generating clock signals; the data multiplexer is used for converting each path of input data into two paths of complementary data; the gating unit is used for carrying out logic operation on the data generated by the data multiplexer and the clock signals to generate control signals; and the current helm unit has an input end connected with the gating unit and is used for receiving control signals and outputting differential current analog signals. Compared with the traditional single-edge triggering DAC Digital-to-Analog Converter), the double-edge triggering DAC sends out data half an hour before or after the DAC conversion clock so as to convert data twice in a clock period, and can obtain twice effective sampling rate of the traditional single-edge triggering DAC at the same clock rate so as to provide users with wider signal bandwidth or higher carrier frequency.

The invention provides a system and a method of power line carrier communication. The system for power line carrier communication comprises a sensor, a transmitting device, a receiving device and a microprocessor, wherein the sensor is connected onto the transmitting device for acquiring environmental information and generating sensing signals; the transmitting device is arranged at one end of the power line for loading the sensing signals to the power line in a condition of power transmission by the power line; the receiving device is arranged at the other end of the power line for detecting sensing signals on the power line; and the microprocessor is connected with the receiving device for analyzing and processing the sensing signals. Through the technical scheme of the invention, a signal line needed by sensor communication and the power line can be combined, the signal transmission efficiency can be improved through a carrier frequency adjustment mode, the number of serial communication lines is reduced and the communication speed is enhanced.

The invention discloses a recovery method of a coherent carrier wave and timing of burst mode GMSK. The recovery method comprises alternatively performing forward operation and reverse operation on same GMSK signals in a square loop feedback loop of a receiving machine. The square loop feedback loop comprises a phase error detection module, a loop filter and a numerically controlled oscillator which are successively connected; an output of the numerically controlled oscillator is further connected with the phase error detection module; and the forward operation is operation performed on a GMSK signal flow arranged according to a receiving time sequence, and the reverse operation is operation performed on the GMSK signal flow arranged according to a receiving time inverted sequence. A real value is gradually approached through the forward operation and the reverse operation, which are alternatively performed on limited-length burst packet data, in the method, and then estimation precision of a frequency of a carrier wave and estimation precision of a phase of the carrier wave are improved. The method is used in an AIS receiving machine, can improve recovery performance of a carrier wave and timing of a signal, can improve receiving performance and can simplify structure of the receiving machine.

A method and apparatus for searching carrier frequencies (CFs) including determining all CFs to be measured within a frequency band according to a predetermined frequency interval; selecting part of the CFs as Sampling Measurement CFs (SMCFs) according to a predetermined band search step, and for each of the SMCFs, calculating initial peak to average ratio (PAR) of the SMCFs; weighting the initial PAR of each of the SMCFs by using initial PARs of SMCFs left and right neighboring each of the SMCFs, to obtain a determined PAR of each of the SMCFs; ordering the determined PARs of all the SMCFs, and selecting, in a descending order of the determined PARs, a predetermined number of SMCFs and frequencies to be measured left and right neighboring the selected SMCFs as a search result.

The invention provides a method and a device for generating X-frequency band one-way ranging signals for deep space exploration. The method provided by the invention can generate one-way ranging sidetone signals in the X-frequency band. The device provided by the invention comprises simulation devices such as a crystal oscillator, a frequency divider, a low-pass filter, a frequency multiplier, a phase shifter and the like, and turn-off of DOR (Differential One-way Ranging) sidetone signals can be controlled through an instruction. The crystal oscillator generates initial reference signals, one path of the initial reference signals are inputted into the frequency multiplier after power division, the frequency multiplier generates X-frequency band carriers, another path of the initial reference signals are inputted into a divide-by-two frequency divider, a left path of the initial reference signals are inputted into a divide-by-ten frequency divider, and two paths of DOR sidetone signals are generated respectively. Phase modulation is carried out on the two paths of DOR sidetone signals in the X-frequency band, and the two paths of DOR sidetone signals are outputted after being amplified and isolated. Divide-by-two frequency division and divide-by-ten frequency division are completed by a decimal counter. The X-frequency band one-way ranging signals generated by using the method provided by the invention can complete a function of accurate ranging for a deep space probe by being matched with relevant ground station equipment, thereby being applicable to the fields of lunar exploration, Mars exploration and the like.

The invention provides a ground user navigation and positioning method based on a Beidou Ka inter-satellite link signal. The method comprises that it is supposed that between epochs k-1 and k (k=1, 2,3...), a user in an area with a Beidou inter-satellite signal reception terminal in the ground generate inter-satellite link unidirectional range finding values with N different Beidou satellites indifferent time, and N range finding equations are obtained; (2) user positions in the range finding equations are reduced to time Tk in a unified way by using a receiver clock model and inertial navigation information; and (3) on the basis of time synchronization of range finding values, the ground user estimates the positions of himself/herself in real time in a Kalman filtering positioning algorithm. Thus, interference and cheating sources aimed at the L-frequency-band navigation signals can be avoided, possible problems caused by failure of the L-frequency-band navigation signals are solvedto certain extent, and the navigation safety of a key area in the special scene is ensured.

The invention discloses a cased well ground signal bidirectional wireless electromagnetic transmission device and a cased well ground signal bidirectional wireless electromagnetic transmission method, and belongs to the technical field of oil-gas field development. When underground data are uploaded, an upper short section I serves as an electromagnetic signal receiving short section, and a lower short section II serves as an electromagnetic signal transmitting short section; when the TM wave transmitting antenna in the short section II generates an alternating magnetic field in the magnetic core through alternating current, the magnetic core on the short section I of the electromagnetic signal receiving short section can capture the current signal so as to upload the signal; similarly, when ground data is downloaded, the short section II serves as an electromagnetic signal receiving short section, the short section I serves as an electromagnetic signal transmitting short section, and when the TM wave transmitting antenna in the short section I generates an alternating magnetic field in the magnetic core through alternating current, current signals are captured in the short section II to complete signal downloading and bidirectional signal transmission between the short section I and the short section II. Compared with the prior art, under the condition of the same transmission distance, the received signal amplitude is larger, and the carrier frequency is higher.

The invention relates to the technical field of mobile communication, and discloses a tunnel leaky cable communication system, i.e., main unit equipment for outputting a multi-channel intermediate frequency modulation signal at an information source part, then the intermediate frequency modulation signal is transmitted by utilizing a leaky cable and is radiated to a space in a tunnel, and the intermediate frequency modulation signal is converted into a multi-channel radio frequency carrier signal at a target working frequency higher than the cut-off frequency of the leaky cable by using vehicle-mounted relay unit equipment arranged on a carriage body of a running train carriage in a tunnel, and the multi-channel radio frequency carrier signal covers the interior of the carriage, so that anovel leaky cable supporting higher cut-off frequency does not need to be redeployed, the deployment cost, the construction cost and the difficulty of a mobile communication signal (especially a 5G signal) leaky cable coverage scheme with relatively high carrier frequency are greatly reduced, and multi-channel communication is supported; and on the other hand, the cooperative base station is adopted to perform system synchronization and equipment management on the vehicle-mounted relay unit equipment, so that the working robustness of the vehicle-mounted relay unit equipment is ensured.

The invention discloses a PFC circuit control method and device, a computer readable storage medium and a controller. The control method comprises the following steps: acquiring an AD sampling value required for controlling the PFC circuit; carrying out reconstruction filtering on the obtained AD sampling value every other at least two carrier periods to obtain a corresponding calculation parameter, and calculating a duty ratio according to the calculation parameter so as to multiplex the duty ratio in the at least two carrier periods; and controlling the PFC circuit according to the multiplexed duty ratio. The duty ratio is calculated every other at least two carrier periods, and the duty ratio is multiplexed, so that the calculated amount of the controller can be effectively reduced, the carrier frequency of the PFC circuit is improved, meanwhile, the controller with high operational capability does not need to be replaced, and the cost is favorably controlled; as the carrier frequency of the PFC circuit is improved, the inductance value and size of the inductor can be further reduced, the power density of the controller is improved, and inductor heating is reduced.

The invention discloses a system and a method for positioning information by the Internet of Things. The system comprises geographic information nodes and a positioning node, wherein the geographic information nodes are distributed in a set area according to a set rule, each geographic information node emits an optical signal with a unique ID (Identity) code to a set direction, and optical signalsemitted by all geographic information nodes do not mutually interfere; the ID code of each geographic information node corresponds to a position coordinate on an electronic map in the set area one byone; and the positioning node matches a position coordinate in the electronic map according to the received ID code. The system has the beneficial effects that the real-time accurate positioning of personnel/ equipment/ articles in a building can be realized by low cost, and positioning information datamation is realized. The system is cooperated with other intelligent equipment, and beneficial help can be provided for other systems or schemes which need to be positioned in real time.

The invention relates to a method for operating a brake of a motor vehicle with at least one electronic brake signal generator, in particular at least one brake pedal, and a brake control device for actuating the brake on the basis of a brake signal of the brake signal generator, wherein the brake signal is transmitted to the brake control device. The method according to the invention is characterised in that the actuation of the brake signal generator and the brake pressure value are transmitted to the brake control device as a brake signal. Finally, the invention relates to a vehicle control device and a vehicle for carrying out the method according to the invention.