44results about How to "Low power spectral density" patented technology

The invention relates to a data processor system for space-based measurement and control of a high-speed aircraft. The data processor system comprises a power supply module, an interface module, a control module, an encryption module, a forward processing module and a reverse processing module, wherein the power supply module is used for providing the secondary power source for the other modules; the control module is used for receiving control instructions, and sending the control instructions to the other modules; the encryption module is used for encrypting the reverse data stream and decrypting the forward data stream respectively; the forward processing module is used for receiving the mid-frequency signal, completing the receiving and processing link, recovering forward information, and outputting the forward information to an external device through the interface module; the reverse processing module is used for receiving image data, flight state information and remote measurement information, generating the mid-frequency signal after completing the launching and processing link to output the mid-frequency signal to an external radio frequency front end, and eventually sending the mid-frequency signal to a ground system. The data processor system supports the carrier high-dynamic measurement and control of the aircraft, is large in region coverage, supports multiple users, can realize real-time two-way communication with the aircraft, and has certain interference capability.

Antenna and satellite communications assemblies and associated satellite tracking systems that may include a low profile two-way antenna arrangement, tracking systems, and applications thereof. Applications for the system include military, civilian, and domestic emergency response applications. The antenna arrangements may be configured to form a spatial multi-element array able to track a satellite in an elevation plane by electronically dynamically targeting the antenna arrangement and / or mechanically dynamically rotating the antenna arrangements about transverse axes giving rise to generation of respective elevation angles and dynamically changing the respective distances between the axes whilst maintaining a predefined relationship between said distances and the respective elevation angles. The system provides autonomous dynamic tracking of satellite signals and can be used for satellite communications on moving vehicles in a variety of frequency bands for military and civilian applications.

A method for providing spectral and temporal stealthy information transmitted over an optical communication channel, according to which, at the transmitting side, the power spectral density of a pulse sequence bearing the information is reduced by encrypting the temporal phase of the pulse sequence. The power of the pulse sequence is spread in the frequency domain, to be below the noise level, by sampling the pulse sequence. Spectral phase encoding is used to temporally spread the pulse sequence and to prevent coherent addition of its spectral replicas in frequency domain. The resulting signal, encrypted both in time and frequency domains, is then transmitted. Spectral phase decoding is performed at the receiving side by performing coherent detection and folding all the spectral replicas of the transmitted signal to the baseband by means of sampling. The temporal phase of the signal is decrypted and the information which is delivered by the pulse sequence is decoded.

A pulse amplitude modulation (PAM) signal generator that injects a copy of a pulse into the PAM baseband signal prior to frequency upconversion and power amplification. The pulse comprises a function of, or an extra copy of, a pulse in the PAM baseband signal. The pulse injector analyzes the PAM baseband signal for times when a predetermined threshold is exceeded and forms a pulse that is constructed and arranged to reduce the amplitude of the PAM baseband signal to a desired peak amplitude when the pulse is added to the PAM baseband signal. In other embodiments the peak-to-RMS amplitude ratio reducing methods and apparatus used to process PAM signal are adapted for reducing peak-to-RMS amplitude ratios of amplitude modulation signals in polar modulation transmitters. Peak-to-RMS amplitude ratio reduction is performed in the quadrature domain, the polar domain, or both the quadrature and polar domains.

A new modulation scheme in UWB communications is introduced. This modulation technique utilizes multiple orthogonal transmitted-reference pulses for UWB channelization. The proposed UWB receiver samples the second order statistical function at both zero and non-zero lags and matches the samples to stored second order statistical functions, thus sampling and matching the shape of second order statistical functions rather than just the shape of the received pulses.

A concealed satellite navigation and positioning system comprises a concealed satellite constellation, a concealed navigation and positioning signal, a concealed navigation and positioning ground master control station, an intelligent receiver and a passive orbit determination station. The concealed satellite constellation is a generic GEO communication satellite constellation and is composed of aC / Ku frequency band GEO commercial communication satellite, an SIGSO small-dip-angle synchronous orbit satellite and an IGSO inclined orbit satellite. The concealed navigation positioning signal is concealed under an original service signal of a generic GEO communication satellite, the signal power is less than one percent of the full-load power of a satellite transponder, the bandwidth of the navigation signal is more than 40MHz, and the signal-to-noise ratio reduction amplitude of the original signal does not exceed 0.3 dB; wherein the concealed navigation positioning ground master controlstation is a concealed navigation positioning fixed station which is fixedly arranged or a concealed navigation positioning vehicle-mounted communication-in-static station which can move along with avehicle; the intelligent receiver comprises an antenna module, a radio frequency module, a baseband processor module and an autonomous navigation module; the passive orbit determination station comprises at least four orbit determination reference stations located on the surface of the earth. The orbit determination base station receiver collects satellite signals, calculates the position correction amount of a measured satellite, counts the orbit determination precision, arranges the satellite position correction amount information into a navigation message, and injects the satellite positioncorrection amount information into the satellite through the concealed navigation positioning ground master control station for positioning by a user.

A novel technique and structure that maximizes the extraction of information from reference pulses for UWB-TR receivers is introduced. The scheme efficiently processes an incoming signal to suppress different types of UWB as well as non-UWB interference prior to signal detection. Such a method and system adds a feedback loop mechanism to enhance the signal-to-noise ratio of reference pulses in a conventional TR receiver. Moreover, sampling the second order statistical function such as, for example, the autocorrelation function (ACF) of the received signal and matching it to the ACF samples of the original pulses for each transmitted bit provides a more robust UWB communications method and system in the presence of channel distortions.

The invention discloses a short burst spread spectrum satellite signal receiving device, and belongs to the technical field of satellite relay communication. The device comprises a sampling and analog-to-digital conversion circuit, a receiving control circuit, a burst detection circuit, a dispreading and demodulating circuit, an interface processing circuit and a power supply circuit. A self-adaptive dynamic amplitude adjustment method is adopted to assist in quickly completing burst signal detection; a PM-FFT method combining partial matched filtering with rapid filtering is adopted to realize rapid capture and carrier frequency offset correction of burst spread spectrum signals; in addition, burst carrier synchronization is completed by adopting a data storage iterative feedback timing error elimination and phase average interpolation method without auxiliary data, and auxiliary carrier recovery and timing synchronization overhead do not need to be additionally increased for a transmission frame. The short burst spread spectrum signal receiving device can demodulate burst spread spectrum modulation signals under the conditions of high dynamic and low signal-to-noise ratio, which are not possessed by a common demodulation method, and is particularly suitable for being used as the short burst spread spectrum signal receiving device in a satellite communication system with high anti-interference and anti-interception requirements.

Methods and apparatus for generating and processing wideband signals having reduced discrete power spectral density (PSD) components are disclosed. A wideband signal having reduced discrete PSD components is achieved by generating data symbols responsive to data for transmission, transforming one or more of the data symbols into a frame including one or more orthogonal frequency division multiplexing (OFDM) symbols, selectively inverting the frame responsive to a pseudo-random data sequence, and modulating wideband signal pulses of the wideband signal with the selectively inverted frame.

The invention discloses a digital intercom system based on MPPSK (M-ary Phase Position Shift Keying) modulation. The digital intercom system is characterized in that the MPPSK modulation is used as a modulation and demodulation manner of a physical layer of a digital intercom. According to special spectrum characteristics of an MPPSK modulated signal, high-speed intercom information is in plug-in transmission by utilizing the spectrum gap or the idle spectrum between adjacent channels in the existing digital intercom system. Normal communication of a receiving end of the system can be ensured only by completing adjacent-frequency or same-frequency interference elimination of the existing digital intercom on a digital base band. An MPPSK system is adopted in a transmitter and used as the modulation manner of the physical layer of the digital intercom; extra spectrum resources are not occupied; the high-speed intercom information is in plug-in transmission only by utilizing the spectrum gap or the idle spectrum between the adjacent channels in the existing digital intercom system; a receiver is only necessary to eliminate adjacent-frequency or same-frequency interference of other digital intercoms on the digital base band; and thus, normal demodulation of the MPPSK modulated signal can be ensured.

The invention, which relates to the field of the coal gangue radar identification system and method, provides a high-speed ultra-wideband radar imaging type coal gangue radar identification system and an identification method thereof. Ultra-wideband pulse signals are transmitted to a coal gangue mixture and echoes generated by passing through the coal gangue by the signals have different phases; and on the basis of a relationship between the echo phases and the phase of the transmitted echo, a relationship between dielectric constants of different media is determined. Since the coal gangue is a weak conductive medium, electromagnetic waves are propagated through the coal gangue interface to generate an incident wave and a reflected wave that have a phase difference and the coal gangue is identified based on the phase difference between the incident wave and reflected wave. Besides, a transceiver antenna is installed at a tail beam of a hydraulic support and is used for transmitting signals, receiving echoes, and transmitting the signals to a data processing system; the data processing system analyzes the phase information of the echoes to identify the gangue in the coal gangue mixture. According to the invention, the influence by the underground humidity or dust is low; the e detection precision and the speed are high; and the labor intensity of the worker is reduced and thus the worker is kept away from the harsh environment.

A method and apparatus for loading, detecting, and monitoring channel-associated signals are provided. Channel-associated signals are identified with spread spectrum codes in the electrical domain, and after being modulated to an optical service signal at respective loading points separately, the channel-associated identification signals are transmitted in the optical channel along with the optical signal. At any downstream detecting point, passing optical signals can be converted through photoelectric conversion, and the channel-associated identification signals are de-spread. By detecting the channel-associated signals, it is possible to learn about whether the upstream loading point work normally, whether the optical channel operates normally, etc., and thereby to find possible failures, solve problems, and monitor quality parameters of optical signals in real time, and improve reliability of the optical signal transmission.

The invention discloses a high-power multi-single-frequency optical fiber laser frequency multiplication system and method. The system comprises a single-frequency laser (1), a phase modulator (2), asignal generator (3), an optical fiber amplifier (4), a spatial isolator (5), a resonance frequency multiplication device (6) and a cavity locking device (7). The method comprises the steps of: performing phase modulation on the single-frequency laser by adopting a periodic signal to generate multiple single frequency lasers, by controlling the frequency interval [delta][omega] of multiple single-frequency lasers, matching [delta][omega] with integral multiples of a free spectral region of the frequency doubling cavity, and changing the modulation depth of the multi-single-frequency laser by controlling the output power of periodic signals, so that the generated multi-single-frequency laser at least contains three frequency spectrum components, the SBS threshold value of the fiber laser isincreased, and high-power and narrow-linewidth frequency doubling laser output is obtained.

A mass analyser in which ions form packets that oscillate with a period has an ion detector comprising: a detection arrangement; and compensation circuitry. The detection arrangement may comprise: a plurality of detection electrodes detecting image current signals from ions in the mass analyser; and a preamplifier, providing an output based on the image current signals. The compensation circuitry provides a compensation signal to a respective compensatory part of the detection arrangement, based on one or more of the image current signals. A capacitance between each of the compensatory parts of the detection arrangement and a signal-carrying part of the detection arrangement affects the signal-to-noise ratio of the preamplifier output. A generator may provide a trapping field defining an ion trapping volume and a shielding conductor may be positioned between two detection electrodes, with a controller applying a voltage to the shielding conductor based on a detected image current.

The invention discloses a railway train anti-collision and anti-rear collision device based on point-to-point precise distance measurement, which includes a self-check module, a first distance measurement module, a second distance measurement module, a first main control module, a second main control module, a second main control module, and a second main control module. An information display module, a second information display module, a first voice broadcast module, a second voice broadcast module, a first sound and light alarm module, a second sound and light alarm module, a first train brake control module, and a second train brake control module A control module, a communication conversion interface and a backup power supply, the output terminals of the backup power supply are respectively connected to the input terminals of the self-test module, the first main control module and the second main control module. The invention can prevent train collisions, prevent front and rear trains from tracking and rear-end collisions, protect key railway facilities, etc., and can provide real-time distance and sensor detection data for railway rolling stock operation tracking, navigation positioning, and intelligent transportation scheduling.

One or more embodiments of the present specification provide an anti-interference communication method and electronic equipment, which can solve the problem of reduced communication quality caused byinter-symbol interference and narrowband interference. The electronic equipment includes a memory, a processor, and a computer program stored on the memory and operable on the processor for performingan anti-interference communication method. The anti-interference communication method comprises the following steps that: a signal sending end allocates an information symbol of initial modulation information to a delay-Doppler domain resource grid to obtain a mixed jump symbol signal, carries out inverse symplectic Fourier transform and Hesenberg transform on the mixed jump symbol signal to obtain a time-domain sending signal, transmits the time-domain sending signal to a communication channel; and a signal receiving end receives the corresponding time-domain receiving signal, carries out Wigner transform and symplectic Fourier transform on the time-domain receiving signal to obtain a receiving signal, performs information symbol sequence detection on the receiving signal, and determinescommunication information sent by the signal sending end.

A data encoding and decoding method capable of lowering signal power spectral density for a binary data transmission system is disclosed. The data encoding method includes receiving binary data, performing adaptive mode tracking encoding for the binary data to generate a first encoding result, performing bit stuffing encoding for the first encoding result to generate a second encoding result, performing bit stationary state resuming encoding for the second encoding result to generate a third encoding result, and outputting the third encoding result.

In one embodiment, a data encoder for a component (such as an integrated circuit) may encode data to be transmitted from the component to another component in a system. The encoder may avoid one or more data patterns that, if transmitted by the component, may cause noise to occur at one or more specified frequencies (or frequency bands). The specified frequencies may be frequencies that are in use for wireless communication by the device. By avoiding noise at the specified frequencies, the desense that might otherwise occur may be reduced or eliminated. Quality and speed of the wireless communication may be increased.

A frequency-doubled laser generating device comprises a single-frequency laser, a phase modulator, a laser amplifier, a spatial isolator and a frequency doubling device which are connected in sequence, and further comprises a signal generator which generates radio frequency or pseudo-random signals and is used for driving the phase modulator and modulating single-frequency laser with the output phase amplitude being Npi, after being amplified by the laser amplifier, the single-frequency laser is emitted into the frequency doubling device through the spatial isolator, single-frequency or narrow-linewidth frequency doubling light with the laser phase modulation amplitude of 2Npi is obtained, and N is an odd number. The phase modulator can realize phase modulation in a wider wavelength range, and meanwhile, high-power low-frequency fundamental frequency light obtained by the laser amplifier is subjected to frequency doubling to obtain single-frequency or narrow-linewidth frequency doubling light, so that the structure has the advantages of being simple, flexible in design and the like; a new technical scheme is provided for high-power and high-stability single-frequency or narrow-linewidth laser frequency doubling, and high practical value and application prospects are achieved.

A method of embedding and transmitting a meta-data message in an original burst carrier signal for message reassembly comprising spreading a meta-carrier signal using a Direct Sequence Spread Spectrum (DSSS) spreading code having a Pseudo-Random Noise (PRN) spreading code sequence, the meta-carrier signal comprising one or more bits of meta-data information about the original burst carrier signal, lowering a power spectral density of the meta-carrier signal using the PRN spreading code such that interference with the original signal is reduced, combining the original burst carrier and the meta-carrier signals using a modulator such that a composite burst carrier signal results wherein the meta-carrier signal occupies at least a portion of a bandwidth of the original carrier, and transmitting the composite burst carrier using a transmitter over a telecommunications channel in which only one burst carrier signal is expected to be present within a predetermined frequency bandwidth at a point in time.

The invention discloses an information modulation method based on data packets. This method divides the binary digital information to be transmitted into a data group with multiple bits as the unit, and divides the data group into two parts, the first part is the waveform selection state bit, and the second part is the time slot position state bit; the code The meta-time is divided into multiple time slots of the same size. The signal transmission waveform lasts for one time slot, and other time slots do not transmit signals. The transmission waveform mapping rule and the time slot position mapping rule are formulated; according to the mapping rule, the The state of the divided waveform selects the state bit to select the shape of the transmission waveform, and determines the time slot position of the transmission waveform in the symbol time according to the state of the divided time slot position state bit in the data group to form a transmission signal. The invention improves the power efficiency of the modulated signal and improves the anti-interference ability of the signal.

A pulse amplitude modulation (PAM) signal generator that injects a copy of a pulse into the PAM baseband signal prior to frequency upconversion and power amplification. The pulse comprises a function of, or an extra copy of, a pulse in the PAM baseband signal. The pulse injector analyzes the PAM baseband signal for times when a predetermined threshold is exceeded and forms a pulse that is constructed and arranged to reduce the amplitude of the PAM baseband signal to a desired peak amplitude when the pulse is added to the PAM baseband signal.

A method and device are provided for producing a transmission signal to be transferred over a transmission path from an input signal, for example an xDSL signal, wherein a bandwidth of the input signal is distributed onto a plurality of frequency bands in such a way that part signals are obtained corresponding to the individual frequency bands, and wherein each part signal is conducted to separate line drivers, and wherein output signals of the individual line drivers are combined to form the transmission signal to be transferred over the transmission path by combination means, which can be designed as an adder. In order to obtain the frequency band which pertains in each case from the input signal, which can be transformed into an analogue signal with a D / A converter, filter means can be used.

The present description relates, according to one aspect, to a high-peak-power laser pulse generation system (10) comprising at least one first light source (101) for emitting first nanosecond laser pulses (IL), a fiber device (110) for transporting said first laser pulses, comprising at least one first multimode fiber with a single core designed to receive said first laser pulses, and at least one first optical amplifier (120) arranged at the output of said fiber device for optically amplifying said first laser pulses in order to form said high-peak-power laser pulses.

The invention discloses a continuous spectrum random signal carrier communication method, which comprises the following steps of: enabling a noise source to generate white noise, and converting the white noise into broadband noise in a preset frequency band by adopting a band-pass filter; amplifying the broadband noise by using an operational amplifier, and modulating the amplified broadband noise by using an information source to obtain a signal with information; processing the signal with the information through a detector to obtain an initial voltage signal; and offsetting noise in the initial voltage signal by adopting a multi-stage cascade circuit of a subtracter and an operational amplifier to obtain and output a final voltage signal. According to the method, spectrum resources are fully utilized through a continuous spectrum carrier modulation mode, a communication system with ultra-low power spectrum density is achieved, and the power spectrum density is lower than that of bottom noise, namely, the signal-to-noise ratio is lower than 1.

The present invention provides a method, an apparatus, and a system for reducing digital subscriber line interference, so as to reduce, as much as possible, or eliminate an influence of a legacy line on a vectored line in a digital subscriber line system. The method includes: identifying at least one legacy digital subscriber line in a digital subscriber line DSL legacy line set; obtaining a target power spectral density mask value of the legacy digital subscriber line; and reducing power spectral density of a transmit signal on the legacy digital subscriber line according to the target power spectral density mask value. The method according to embodiments of the present invention can achieve an effect of eliminating far end crosstalk caused on a Vectored DSL line without upgrading or replacing a VDSL2 Legacy CPE, thereby reducing time consumed by the upgrade, and eliminating human and material (such as device) costs caused by the upgrade.