88results about How to "Wide signal bandwidth" patented technology

The present invention is related to methods and apparatus that compensate for quadrature impairments of an analog quadrature modulator and / or demodulator over a relatively wide signal bandwidth. One embodiment pre-distorts baseband signals in a quadrature modulator compensation signal processor (QMCSP) to negate the quadrature impairment of an analog quadrature modulator and corrects a received baseband signal in a quadrature demodulator compensation signal processor (QDCSP) to cancel the quadrature impairment of an analog quadrature demodulator. The QMCSP and the QDCSP contain adaptive digital filter correction structures that pre-compensate and post-compensate, respectively, for the quadrature impairments introduced by the analog quadrature modulator and the analog quadrature demodulator over a relatively wide bandwidth. A phase shifter advantageously shifts the phase of a local oscillator signal to the analog quadrature demodulator to distinguish quadrature impairments introduced by the modulation path from quadrature impairments introduced by the demodulation path.

The invention relates to a semiconductor laser, in particular to a no-time-delay flat-frequency-spectrum broadband photon integrated chaos semiconductor laser which solves the problems that chaos lasers generated by an existing semiconductor laser have the time delay characteristic, the signal band width is small, and the frequency spectrum is not flat. The no-time-delay flat-frequency-spectrum broadband photon integrated chaos semiconductor laser comprises a chip substrate, an optical waveguide, an erbium-doped passive optical waveguide, a left distributed feedback semiconductor laser chip, a no-isolation two-way amplified semiconductor light amplification chip, a right distributed feedback semiconductor laser chip and a high-speed photoelectric detection chip. The no-time-delay flat-frequency-spectrum broadband photon integrated chaos semiconductor laser is suitable for the fields of synchronization of chaos, secrecy light communication, high-speed random number secret key generation, laser radar, optical fiber network fault detection, ultra broadband technology, distributed optical fiber sensing and the like.

The present invention is related to methods and apparatus that compensate for quadrature impairments of an analog quadrature modulator and / or demodulator over a relatively wide signal bandwidth. One embodiment pre-distorts baseband signals in a quadrature modulator compensation signal processor (QMCSP) to negate the quadrature impairment of an analog quadrature modulator and corrects a received baseband signal in a quadrature demodulator compensation signal processor (QDCSP) to cancel the quadrature impairment of an analog quadrature demodulator. The QMCSP and the QDCSP contain adaptive digital filter correction structures that pre-compensate and post-compensate, respectively, for the quadrature impairments introduced by the analog quadrature modulator and the analog quadrature demodulator over a relatively wide bandwidth. A phase shifter advantageously shifts the phase of a local oscillator signal to the analog quadrature demodulator to distinguish quadrature impairments introduced by the modulation path from quadrature impairments introduced by the demodulation path.

An ultra-low noise, high gain interface pixel amplifier is provided with capability for single-photon readout of standard photodetectors at high electrical bandwidths for diverse spectral bandpass from the x-ray to long IR bands. The detector charge modulates a source follower whose output is double sampled to remove correlated noise by a compact stage that also provides optimum level shift for subsequent amplification of the full signal excursion. The level-shifted signal finally drives a compact amplifier that generates a robust end-to-end transimpedance. Single-photon readout of photodetectors at high electrical bandwidths in small pixel areas is thereby facilitated.

The invention relates to a system utilizing CMMB (China mobile multimedia broadcasting) signals to detect a target and a method thereof. The system comprises a receiving antenna, an analog chassis with a signal simulating and receiving component, a CPCI (compact peripheral component interconnect) chassis with a signal acquisition and processing component, at least one disc array chassis with a signal storage component, a switchboard and a signal process for signal processing, which are connected in sequence. The analog reception adopts a scheme of secondary mixed frequency and fixed medium frequency; the data acquisition adopts a scheme of medium-frequency bandpass sampling and digital down-conversion; the data storage adopts a high-speed disc array; and the data processor is used for implementing such operations as signal reconstruction, channel correction, direct wave suppression, digital beam formation, inter-ambiguity function, peak detection, constant false alarm detection, positioning and tracking and the like, and final output of information of the target distance, speed and direction. The system has the following advantages of no need for frequency distribution, no electromagnetic pollution, high signal randomness, high signal interception performance, large signal bandwidth, high distance resolution, low research and maintenance cost, and high mobility.

The invention provides an optical-receiver preamplifier for receiving analog or digital optical signals. The preamplifier comprises a high-gain amplifier A1, an input circuit, a negative-feedback impedor Zf, a low-gain amplifier A2 adjustable in gain and a feedback capacitor Cff, wherein the input circuit takes a photoelectric converter as a main component; the negative-feedback impedor Zf is connected with the reverse input end and the output end of the A1; the feedback capacitor Cff connects the output end of the A2 with the reverse input end of the A1; and the output end of the A1 can be directly connected with the input end of the A2 or can be connected with the input end of the A2 through a buffer. Output signals of the preamplifier are taken out from the output end of the A1 or the output end of the buffer, and can be directly subjected to subsequent signal processing or be further amplified and then subjected to subsequent signal processing.

The invention discloses a test method for current noise of a high-resistance device and a medium material, comprising the following test steps: firstly, arousing the low-frequency current noise of a high-resistance sample by utilizing a sample adapter; then amplifying the sample low-frequency noise by utilizing a low-noise current amplifier; collecting amplified noise signals by utilizing a data acquisition card; calculating the power spectrum density S0(f) of the collected current noise signals of which the high-frequency parts are attenuated by the amplifier; obtaining the amplitude-frequency characteristic curve of the current amplifier by utilizing a locking amplifier, and calculating a normalized curve Q(f) according to the amplitude-frequency characteristic curve; reducing the attenuated power spectrum density S0(f) by utilizing the Q(f), thus obtaining a power spectrum density curve S(f) of a reduced band spread; and finally, carrying out data analysis on the S(f) to screen devices or research sample reliability. By utilizing the test method, the problems of narrow times-number transmission band and insufficient test data in the existing test method for high-resistance sample noise are solved; and the test method provided by the invention has the advantages of high efficiency, automated operation and high precision of reduced data.

The invention discloses a simplified device for generating frequency-doubling millimeter wave which belongs to the field of millimeter wave generation in the radio-over-fiber (ROF) communication techniques and is based on the four-wave mixing effect in the optics. The invention uses the modulation inhibited by photo-carrier wave, the four-wave mixing (FWM) effect and the optical filter theory as well as a Mach-Zehnder modulator, and mixes a local oscillation (LO) signal and a baseband digital signal to be used for inhibited modulation of the optical signal carrier, and after the modulation signal is power amplified, the invention forms a new mixing sideband respectively at both sides of two first sidebands through a four-wave mixing (FWM) unit. The invention adopts an adjustable harmonic filter for filtering the original two first sidebands, and implements the beat frequency of the two new mixing sidebands at a photoelectric detection end, thus forming a millimeter wave signal with six octaves. The scheme can lower the frequency of the local oscillation signal source that is used and reduce the bandwidth requirements of the mixer and the optical modulator; therefore, the proposal of the invention saves system cost on the basis of increasing signal bandwidth and improving frequency spectrum utilization ratio.

A method and apparatus for measuring particle motion using electromagnetic radiation uses beams of radiation modulated with a distinct frequency and / or phase. A particle traversing these beams scatters a portion of the radiation. Scattered radiation, which retains its modulation information, is then detected, and a cross-correlation technique is used to quantify the particle's motion, for example, particle velocity.

A power amplifier arrangement having a distributed antenna is disclosed. The power amplifier arrangement has two or more signal paths which are coupled to a common input. Each signal path has an amplifier with a downstream antenna. The respective signal paths with the antenna are activated or deactivated by a control device as a function of the desired gain or output power. This results in high efficiency over a wide frequency range. The polar diagrams of the antenna branches preferably correspond to those of a single antenna.

An optical-waveguide grating modulator is compatible with high-frequency electrical modulation signals of limited bandwidth. The modulator comprises an optical grating formed in an optical waveguide constructed from electro-optic (EO) material and an electrode that is an RF waveguide or RF transmission line that conducts a traveling-wave electromagnetic (EM) field and that contains a portion of the optical-grating waveguide with a continuous grating. The RF input modulation signal is coupled into an RF EM field that propagates through the RF waveguide or transmission line in a direction that is parallel to the direction the light propagates in the optical-grating waveguide and that EM field overlaps the optical-grating waveguide. The light travels along the optical-grating waveguide preferably at the same velocity as the RF EM field travels along the RF waveguide or transmission line.

The invention relates to an optical fiber radio communication system, in particular to a quadruple-frequency dual-millimeter wave optical fiber radio communication system. The optical fiber radio communication system uses a Mach-Zehnder modulator to apply local oscillator signals to the suppressed carrier modulation of optical signals so as to generate first-order sidebands and third-order sidebands, and uses an optical interleaving multiplexer to separate four sidebands into two groups so as to form a sideband module of which the frequency difference is four times that of the local oscillator signals. An optical filter filters out single sidebands in the two groups of the sidebands respectively and the single sidebands are loaded with data, and then a four-port optical coupler is used for equalizing the frequency of the four sidebands and transmitting the frequency to a base station. The optical fiber radio communication system uses the optical interleaving multiplexer in the base station to divide signals into two groups and generate quadruple-frequency electric millimeter waves through optical detector beat frequency, so the frequency of a local oscillation signal source can bereduced, and double quadruple-frequency optical millimeter wave signals can be generated by adopting an optical modulator. Besides, the optical fiber radio communication system loads data unilaterally to reduce error code crosstalk, increase the signal bandwidth and improve the system performance, and saves the system manufacturing cost on the basis of improving the frequency spectrum utilizationratio.

The invention relates to a quasi-real-time cable-free network seismograph system based on an ultra wide band wireless module. The system is provided with a display and control central station and multiple groups of acquisition nodes. The display and control central station is provided with a host computer, an ultra wide band wireless module A, an epicenter trigger, an intelligent battery, and a voltage stabilization module A. Each group of acquisition node is provided with a single-chip microcomputer module, an ultra wide band wireless module B, a signal conditioning and data acquisition module, an intelligent battery, and a voltage stabilization module B. All the acquisition nodes are arranged into 14 groups, each group assigns an aggregation node, other acquisition nodes in the group send data to the aggregation node in order, and all the aggregation nodes then send the data to the display and control central station. After being started up, the system can self-organize wireless Internet of Things, and the ultra wide band wireless modules A, B work at 3.1-10.6GHz. The system is small in size, light in weight, low in cost, low in battery power consumption and high in interference resistance. Relative positions of the nodes can be resolved automatically, an error range of the positioning precision is from -1.0cm to 1.0cm, and the synchronization precision is 1[mu]s. The system is suitable for being popularized and applied in the field of geological exploration.

The invention discloses an unmanned aerial vehicle airborne anti-collision radar system and a working method. The system comprises a transmitting board, a receiving board, a power board, a signal processing board and a display control terminal. The method comprises the steps of receiving motion parameters and instructions of an unmanned aerial vehicle platform; generating a system control instruction, a reference clock, a time sequence signal and an emission excitation signal; performing emission signal power division, signal phase shift, signal filtering and signal space radiation; receiving echo signals; performing amplitude limiting, low noise amplification and filtering on the received signal; down-converting the echo signal; filtering and amplifying the intermediate frequency signal and controlling the sensitivity frequency; performing AD sampling on the intermediate frequency signal; processing radar echo signals and radar data; packaging and processing target point track information and BIT information; and sending and displaying the target information and the BIT information. The method has the advantages that cooperative and non-cooperative flight targets in the air can be effectively detected, and target point track information is formed; multiple flying targets can be effectively detected and distinguished, and the system is suitable for airborne installation of an unmanned aerial vehicle; and the system cost is low.

The invention discloses an ultra-wideband laser communication and ranging integration device and method, which belong to the technical field of laser communication and laser ranging. The device comprises a host computer display and control module, an ultra-wideband signal generating module, an uplink laser emitting assembly, an uplink laser receiving assembly, an uplink signal collecting and clockrecovery module, a signal forwarding module, a downlink laser emitting assembly, a downlink laser receiving assembly, a downlink signal collecting and capture tracking module, a ranging information processing module and a communication demodulation module. Based on a pulse position modulation mode, the relative position of the pulse is used to transmit the communication data, sinusoidal carriersare not needed, ultra-narrow pulses of a nanosecond level are directly emitted, the spectrum utilization rate is high, the extremely narrow pulse width can obtain high time resolution, and the laser ranging precision can be improved obviously. The average emitting power can also be effectively reduced, and the device and the method are applied to ultra-long-range deep space detection laser communication and ranging integration.

A system for communicating over a power cable has a power line connected to a power source at one end, a switch mode transformer connected to the power line at the other end for transforming voltage received from the power source through the power line, modulation of the switch mode transformer, and a receiver situated at the power source end and adapted to detect and process ripple signals from the switch mode transformer propagated on the power line.

The invention provides a precise synchronization-unrequired coal mine underground spread spectrum accurate ranging method and a device. According to the precise synchronization-unrequired coal mine underground spread spectrum accurate ranging method, a parallel and tracking loop-free pseudo-noise code synchronization accurate measurement algorithm is adopted, such that higher time resolution can be obtained based on rough synchronization without precise synchronization process required, and therefore, ranging pseudo code speed can be decreased, and bandwidth occupied by ranging pseudo codes is limited below 100MHZ, and thus, meter-level positioning accuracy can be achieved. The device for realizing the method comprises a communication control module and a wireless response module; the communication control module, adopting a high-performance FPGA as a core processor, mainly comprises a transmitter and a receiver; and the wireless response module de-spreads received signals through adopting a search-track-free synchronization mode without a separate processor required. The precise synchronization-unrequired coal mine underground spread spectrum accurate ranging method and the device of the invention can inhibit serious electromagnetic interference under a coal mine, and are advantageous in robust hardware designs, redundant algorithms, high-accurate ranging and strong real-time property, are suitable for a coal mine underground personnel precise positioning system.

An optical amplifier with improved output power utilizing less optical fiber components and reduced noise is disclosed. A first optical fiber amplifier is pumped by a first light source prior to splitting into a number of sub-bands, and a second optical fiber amplifier is pumped by a second light source. One of the sub-bands is amplified in multiple stages using a reflector, by passing the amplified sub-band back into the second optical amplifier in a reverse direction. Thereafter, all amplified sub-band signals are recombined to produce an output signal.

Provided are a Raman amplifier and a Raman pumping method. A light source unit outputs a pumping light having a wavelength that periodically changes. A light intensity control unit varies a light intensity of the pumping light using the pumping light to improve the gain flatness of a Raman gain. A control unit directs the light intensity control unit to control the light intensity of the pumping light in synchronization with changes in the wavelength of the pumping light.

The invention provides a safety inspection system based on conjugate electromagnetic transmit-receive array broadband detection and visual display and a method thereof. The safety inspection system comprises a safety inspection detection front-end, a data processing background and a supporting frame. Conjugate electromagnetic transmit-receive units are provided at the safety inspection detection front-end so that transmitting and non-interference and low-interference directional magnetic receiving of a broadband detection magnetic signal can be realized. Coils are wound on two coil cores with the same geometrical shape so that conjugate electromagnetic transmitting pair are formed. A coil winding mode and the size and direction of current in the coils are adjusted so that magnetic field intensity of the coils at the geometric centre is enabled to be zero. Multiple conjugate electromagnetic transmitting pairs sharing the geometric centre are combined to form conjugate electromagnetic transmitting units. Directional magnetic receiving elements are arranged at the positions with no magnetic field or weak magnetic field of the conjugate electromagnetic transmitting units so that the conjugate electromagnetic transmit-receive units are obtained. The detected and received signals are processed and color-displayed at the data processing background. The size, the attribute and the position of a metal conductor can be rapidly and accurately detected and displayed by the system.

An analog-to-digital converting system includes at least one first main analog-to-digital converting unit, at least one second main analog-to-digital converting unit, at least one auxiliary analog-to-digital converting unit, and a calibration unit. Each first main analog-to-digital converting unit is located on a first channel. The first channel includes sample period. Each first main analog-to-digital converting unit receives a first sampling value. Each first sampling value includes a first sample clock. An analog-to-digital converting method calibrates timing-skew of the analog-to-digital converters by delaying a time difference on the sampling value.

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 relates to a satellite navigation signal generating method based on chip-level pulse time hopping. The method includes: baseband spread spectrum modulation, wherein a signal pseudo-codegenerator generates a signal pseudo-code, and the same and an encoded message are modulated together after chip shaping to obtain a baseband spread spectrum signal; chip time hopping modulation, wherein a frequency hopping pseudo-code generator generates a frequency hopping pseudo-code sequence, a chip gating pulse generator is controlled to generate a chip gating pulse, and chip time hopping modulation with the baseband spread spectrum signal is carried out to obtain a chip time hopping signal; and radio frequency modulation, wherein a carrier generator generates a radio frequency carrier, radio frequency modulation with the chip time hopping signal is carried out to generate a radio frequency signal, generating of a satellite navigation signal based on chip-level pulse time hopping is completed after amplification and filtering, and the same is broadcast and sent to a user through an antenna. The method realizes improvement of anti-interference ability, maintains compatibility with an existing satellite navigation signal system at the same time, and supports high-precision application based on carrier phase measurement.

The embodiment of the invention provides an uplink data transmission method and device. The method is applied to the electronic equipment. The electronic equipment comprises a wireless transceiver unit and at least two radio frequency units, the radio frequency unit is in communication connection with the wireless transceiver unit. The radio frequency unit comprises an envelope tracking ET power supply module, and the method comprises the following steps: according to a first preset condition, packaging an original uplink data packet into at least two sub-data packets, and respectively sendingthe sub-data packets to at least two radio frequency units of the electronic equipment through a wireless transceiver unit of the electronic equipment; and sending the sub-data packets to a network side in parallel through the radio frequency unit. According to the embodiment of the invention, the problem that the current consumption is difficult to reduce while the data transmission rate is increased in the prior art is solved.

The invention discloses an electronic confrontation simulation detection system and relates to the technical field of radar. The system comprises a main control unit, a variable frequency unit group,a power amplification unit, K antenna assemblies and a power supply unit. The main control unit comprises a control module, a reference source module and a routing module. The control module is achieved based on the FPGA and comprises multiple DDSes. The control module is connected with a host and the routing module. The output end of the reference source module is connected with the control module, the routing module and K variable frequency channel units. The output end of the routing module is connected with K variable frequency channel units in the variable frequency unit group. The variable frequency channel units correspond to different working frequency bands. The output end of each variable frequency band channel unit is connected with a solid state power amplification module in the power amplification unit. The output end of each solid state power amplification module is connected with an antenna assembly. The system is characterized by big application range, high flexibility,onsite compatible scenario, and portability.

The invention provides an SMA link double spreading code signal multiplexing method, which can significantly improve the relay satellite system S-band phased array multi-access link SMA transmission ability and the multi-target service ability and increase the signal bandwidth utilization rate. According to the technical scheme of the invention, in an uplink modulator at the relay satellite transmitting end, primary spreading code signals generated by N paths of array elements are subjected to secondary spreading treatment to generate double spreading code signals, one path of single-carrier reference signals generated by a crystal oscillator are subjected to the same spreading treatment, the N paths of array elements of double spreading code signals which keep synchronization are additively synthesized into one path of signals; and a relay satellite ground receiving system guides the N paths of secondary spreading signals to despread through firstly despreading the reference signals, the signals are combined into one path of signals through a digital beam synthesizer, the synthesized one path of signals are outputted to a baseband of the receiving end for primary spreading signal dispreading and demodulation, and each path of array element signals is restored.

A switchable gain amplifier is provided. The first amplifier unit includes a first input terminal to receive input signals, a control terminal, and a first output terminal to output a first output signal corresponding to the first gain mode. The second amplifier unit includes a second input terminal, and a second output terminal to output a second output signal corresponding to the second gain mode. The switch unit is serially connected between the first and second input terminals. When the switch unit is turned off and the control signal is in the first level, the gain amplifier is set in the first gain mode, whereas when the switch unit is turned on and the control signal is in the second level, the gain amplifier is set in the second gain mode.

The invention relates to the field of sampling control signal processing, in particular to an over-sampling signal processing method for PWM (pulse width modulation) sampling control. Along with the development of the electron technology, the computer information processing speed is greatly accelerated, and the result shows that the control signal sampling frequency can be greatly improved. The optimal switch frequency of a power switch device in a high-powder PWM circuit is much smaller than the signal sampling frequency allowed by a computer. In one PWM control period, a control signal can be subjected to multiple sampling and operation, i.e. over-sampling. Therefore more system information can be obtained; the performance of a sampling control system is improved. The over-sampling signal processing method has the advantages that the defects of single sampling are overcome; the advantages of an over-sampling average method are combined; a novel over-sampling signal processing method is provided; the signal frequency bandwidth can be improved; the inherent carrier wave interference of the PWM circuit is inhibited; the control precision is improved; the transient response speed of the PWM sampling control system is accelerated; the high-frequency signal tracking capability of the PWM sampling control system is improved.

The invention relates to an optical fiber wireless transmission system. The optical fiber wireless transmission system comprises a central station and a base station connected with the central station by an optical fiber link; the central station comprises a single-mode laser of a single-longitudinal-mode optical carrier wave for generating designated wavelengths, a radio frequency sine wave signal source for generating low-frequency radio frequency signals, a Mach-Zehnder modulator for modulating optical carrier waves, a direct-current bias voltage source for providing bias voltage for the Mach-Zehnder modulator, and a light intensity modulator; output ends of the single-mode laser and the radio frequency sine wave signal source are connected with an input end of the Mach-Zehnder modulator; the bias voltage of the Mach-Zehnder modulator is the half-wave voltage of the Mach-Zehnder modulator, the output signal of the Mach-Zehnder modulator is a zero-step and four-step sideband, and the output end of the Mach-Zehnder modulator is connected with the input end of the light intensity modulator; the input end of the light intensity modulator is also connected with a data signal source; an output signal of the light intensity modulator is output to the base station by the optical fiber link. The invention can generate a sideband mold with the frequency difference greater than a local oscillation signal by eight times, and a low-frequency local oscillation signal can be utilized for generating high-frequency millimeter waves.

The invention discloses a high-sensitivity piezoelectric ceramic material, and a preparation method and application thereof. The piezoelectric ceramic material comprises a core component and an additional component, wherein the core component comprises 65.07%-67.73% of Pb3O4, 2.213%-2.3% of SrCO3, 0.291%-0.303% of Sb2O3, 1.328%-1.382% of Nb2O5, 0.165%-0.172% of Ni2O3, 0.08%-0.083% of Fe2O3, 11.51%-11.983% of TiO2 and 17.35%-18.06% of ZrO2 based on the weight percentage; and on the basis of the sum of the core component by weight, the additional component, comprising 0.03-0.1% of SiO2 and 0.2-0.5% of CeO2, is added. Besides, the invention also provides a preparation method and application of the piezoelectric ceramic material. The invention has the advantages of great signal bandwidth, high amplitude, favorable sensitivity and stable long-time operation performance, and can effectively satisfy the special requirements of the electronic complete machine with special requirements for the piezoelectric ceramic sensor.