49results about How to "Reduce noise power" patented technology

Techniques for direct modulation of a switching-mode power amplifier with adaptive digital predistortion are disclosed. A baseband digital modulated signal is decomposed into an amplitude signal and a phase signal in polar coordinates. The amplitude signal is used to modulate supply voltages of the power amplifier. The phase signal is used to modulate a voltage-controlled oscillator (VCO) of a phase-locked loop (PLL), which generates a phase-modulated radio-frequency (RF) carrier coupled to the input of the power amplifier. The digital predistortion is implemented by using a feedback demodulator, which regenerates the baseband amplitude and phase information from the output of the power amplifier. The VCO drift and other non-linear effects of the power amplifier are compensated. High power efficiency and high linearity for different modulation standards are achieved.

A rechargeable multipurpose power management system has a power management system that can include a plurality of power management units. The power management units sources can be individually activated and deactivated (I think there might be a confusion between power sources and the system. Everything is within one box itself (the image that I sent you). Each unit is a power management system that can be connected to a variety of INPUT power sources. Several power management units can be combined together to create a stack of them but each one can operated individually as well). and each one is configured to be coupled to a variety of inputs. A rechargeable battery is coupled to the (One rechargeable battery is attached to only one power management units). A charging controller provides regulated charging to the battery. A plurality of convertors are (do we need to specify here what kind of converters, like DC-DC converters) coupled to the battery and provide output voltages that are accessible individually. A plurality of sensing circuits sense external signals and provide selective activation or deactivation of the system.

An analog to digital converter comprising an Nth analog to digital converter and an N+1th analog to digital converter arranged in series such that a residue signal from the Nth analog to digital converter is provided as an input to the N+1th analog to digital converter, characterised in that a bandwidth control means is provided in a signal path for the residue signal and the bandwidth control means is controlled so as to have a first bandwidth during a first period following generation of a conversion result from the Nth analog to digital converter, and a second bandwidth less than the first bandwidth in a second period following the first period.

The invention provides a UV detector and a preparation method thereof. The UV detector comprises a substrate. The substrate is successively provided with an n-type layer, an i-type superlattice multiplication layer, an i-type photosensitive absorption layer and a p-type layer. The n-type layer is provided with an n-type Ohmic electrode, the p-type layer is provided with a p-type Ohmic electrode, and the i-type superlattice multiplication layer is a superlattice of group-III nitrides. According to the invention, the problem of difficulty in detecting weak ultraviolet light due to UV detector insensitivity caused by similar ionization coefficients of electrons and cavities by use of a conventional UV detector in the prior art is solved.

The invention relates to a robust twin-channel restraining method and a system for civil aviation ground-air radio CM interference. The invention comprises the steps as follows: two-way VHF signals received by a double antenna array are transformed into intermediate frequency digital signals; two-way intermediate frequency digital signals respectively act filtering extraction and orthogonal transformation; two-way complex signals after the orthogonal transformation is transmitted to a monitoring module for judging, if no interference exists, one undisturbed signal in the two-way complex signals is output, and if the interference exists, the two-way complex signals are transmitted to an adaptive interference suppression module based on a CM array for the interference suppression, thus the signal attribute output by the CM array is judged and corresponding action is adopted, the signal is directly output if the array outputs an amplitude-modulated signal, otherwise the signal is output after adaptive interference cancellation; the undisturbed signal output from the steps of the invention is demodulated, and then the high-frequency noise is filtered, the undisturbed signal then is transmitted into a D / A converter to output an aural signal. By adopting the method that the invention judges the signal attribute output by the CM array and then executes corresponding operation, the false lock of the CM array is avoided, and the robustness of an adaptive interference suppression system is effectively enhanced.

In various embodiments, the invention provides a clock generator and / or a timing and frequency reference, with multiple operating modes, such power conservation, clock, reference, and pulsed modes. The various apparatus embodiments include a resonator adapted to provide a first signal having a resonant frequency; an amplifier; a temperature compensator adapted to modify the resonant frequency in response to temperature; and a process variation compensator adapted to modify the resonant frequency in response to fabrication process variation. In addition, the various embodiments may also include a frequency divider adapted to divide the first signal having the resonant frequency into a plurality of second signals having a corresponding plurality of frequencies substantially equal to or lower than the resonant frequency; and a frequency selector adapted to provide an output signal from the plurality of second signals. The output signal may be provided in any of various forms, such as differential or single-ended, and substantially square-wave or sinusoidal.

The invention discloses a two-way multi-order related detection method for a dual-polarization weather radar. The method comprises the following steps: obtaining I / Q (in-phase / quadrature) data of an H (horizontal) channel and a V (vertical) channel; calculating the coherent integration quantities of the H channel and the V channel; calculating the zero-order self-correlation, first-order self-correlation and zero-order cross-correlation quantities of the H channels and the V channels; calculating the weight sum of the multi-order correlation quantity; comparing the weight sum with a threshold value, judging if a weather echo is generated, and if so, calculating the signal-to-noise ratio of the H channel; calculating reflectivity factors under different signal-to-noise ratios; and controlling the quality according to the reflectivity factors, and outputting results. According to the method, the weight sum of the multi-order correlation quantity is introduced in combination with horizontal and vertical polarization echo signals to change a conventional method which simply takes the signal-to-noise ratio of the H channel as a detection factor so as to achieve the purposes of reducing the background noise power and increasing the weak signal detection level, and reduce the loss of the signal-to-noise ratio of an echo wave in a double-transceiver mode.

A wireless communication system for geographically controlling a communication area includes an access point for communicating with a terminal in a first area, and a jammer for generating noise for intercepting communication between the access point and a terminal in a second area. A jamming boundary for dividing an area in which the terminal can communicate with the access point and an area in which the terminal cannot communicate with the access point in an area in which the first area and the second area are overlapped is formed, and the jamming boundary is formed by a ratio between power of a signal transmitted to the terminal by the access point and power of a signal of the noise.

A noise attenuation device for testing a jet engine.

A sampling frequency offset estimation apparatus of an orthogonal frequency division multiplexing (OFDM) system according to an aspect of the invention may include: a first differential operation unit performing complex conjugate multiplication of scattered pilots of complex symbols subjected to a fast Fourier transform (FFT) in an OFDM receiver; an interpolation unit repeating an operation of obtaining a median complex symbol between two consecutive symbols among complex symbols having first phase difference information from the first differential operation unit by a predetermined number; a second differential operation unit performing complex conjugate multiplication of two consecutive median complex symbols among median complex symbols from the interpolation unit; and a sampling frequency offset estimation unit estimating sampling frequency offset using complex symbols having second phase difference information from the second differential operation unit.

The invention relates to the field of wireless signal positioning technology and specifically relates to a virtual multi-station TDOA positioning method and device applicable to a complex environment.The method is characterized in that two to three receivers used for receiving data sent by a positioning transmitting device are arranged; by utilizing a property of the receivers of continuous movement during a positioning process, TDOA data collected by the receivers passing a geographic position is taken as TDOA data collected by a virtual receiver at the geographic position, so that the two to three receivers simulate multiple receivers and multi-station positioning having a station number greater than actual receiver station number is formed for acquiring data information, and proper positioning points are judged by utilizing data relevance; when working, the receivers receive signals transmitted by a transmission device to be positioned through an antenna and send the signals to a processor through a wireless uploading method for process, so that positioning of the transmission device to be positioned is realized. Compared with the prior art, the positioning precision is improved.

Provided is a motor controller for controlling a motor system including a power converter, a smoothing capacitor and a three-phase AC motor. The motor controller includes a generation unit configured to generate a modulation signal by adding a third harmonic signal to a phase voltage command signal, and a control unit configured to control an operation of the power converter using the modulation signal. The third harmonic signal includes a first signal component that causes an absolute value of a signal level of the modulation signal to be greater than an absolute value of a signal level of the phase voltage command signal at a timing in which an absolute value of a signal level of a phase current becomes minimum in each phase

The invention relates to a high-precision and low-distortion digital-analog converter which comprises an analog adder / subtractor, first and second analog integrators, an analog adder, an analog-digital converter, first, second and fourth gain amplification stages, an analog gain stage and a feedback gain amplification stage. A signal output end OUTPUT is connected with an output end of the analog-digital converter, a second-order DEM (dynamic element matching) module is arranged between the analog-digital converter and the analog adder / subtractor, an input end of the second-order DEM module is connected with the output end of the analog-digital converter, and an output end of the second-order DEM module is connected with an input end of the analog adder / subtractor by a digital-analog converter. The high-precision and low-distortion digital-analog converter has the advantages that owing to a feedback factor adding mode, zero points are imported into noise transfer functions, accordingly, noise power in signal base bands can be reduced, the signal-to-noise ratio of the high-precision and low-distortion digital-analog converter can be increased, and the system precision of the high-precision and low-distortion digital-analog converter can be improved; second-order suppression can be carried out on mismatched noise by the aid of second-order sigma-delta DEM technologies, accordingly, the signal-to-noise distortion ratio of the integral sigma-delta analog-digital converter can be increased, and the spurious-free dynamic range of the integral sigma-delta analog-digital converter can be expanded.

The invention discloses a mirror point high dynamic suppressing correlator adaptive to a spaceborne GNSS-R receiver. The correlator comprises a direct signal tracking module (1), a delay module (2), a mirror point high dynamic suppressing control module (3), a mirror point high dynamic suppressing processing module (4), a mirror point high dynamic suppressing infusing module (5), a carrier compensation module (6) and an interference processing module (7). The certain delay processing is performed on direct signals after carrier tracking firstly, the mirror reflection high dynamic suppressing is performed, interference processing is performed on reflection signals after carrier compensation, and the two-dimensional delay Doppler correlation power is acquired finally. The correlator is used for producing local copying carriers, local copying code generation is omitted, interference processing is performed on the direct signals and reflection signals after delay Doppler compensation processing, the Doppler frequency shift of one mirror reflection point in different sampling times can be acquired, the speckle noise of a mirror reflection region is suppressed, and the signal-noise ratio of the signals is increased.

The invention provides a digital decimation filter. The digital decimation filter comprises a cascade integral comb filter, a cascaded Lagrange half-band filter and an FIR filter, which are orderly connected. The digital decimation filter has the advantages of less pass band dropping, small quantized noise power after filtering, and less power consumption.

A rechargeable multipurpose power management system has a power management system that can include a plurality of power management units. The power management units sources can be individually activated and deactivated (I think there might be a confusion between power sources and the system. Everything is within one box itself (the image that I sent you). Each unit is a power management system that can be connected to a variety of INPUT power sources. Several power management units can be combined together to create a stack of them but each one can operated individually as well). and each one is configured to be coupled to a variety of inputs. A rechargeable battery is coupled to the (One rechargeable battery is attached to only one power management units). A charging controller provides regulated charging to the battery. A plurality of convertors are (do we need to specify here what kind of converters, like DC-DC converters) coupled to the battery and provide output voltages that are accessible individually. A plurality of sensing circuits sense external signals and provide selective activation or deactivation of the system.

The invention discloses a coaxial photoelectric component, which includes a tube base and a lens tube cap installed on the tube base, and a transimpedance amplifier and a PIN diode are arranged in the lens tube cap, and the top of the transimpedance amplifier PINA pads, PINK pads and pin pads are arranged on the surface, the bottom surface of the transimpedance amplifier is pasted on the surface of the tube base, the PIN diode is pasted on the top surface of the transimpedance amplifier, and the PIN diode The positive and negative poles of the electrode are respectively connected to the PINA pad and the PINK pad through wires, and the pin pads are connected to the pins on the surface of the socket through wires. Avoid the lead wires connecting the transimpedance amplifier and the PIN diode close to the lead wires connecting the transimpedance amplifier and the tube socket to prevent electrical crosstalk between the leads, reduce noise power, and improve sensitivity.

The invention discloses a direction-of-arrival angle detection method which includes the steps: S1, receiving data signals s (t); S2, converting the data signals s (t) received by a vector array for the t time into a vector form by a vibration velocity sensor and outputting the data signals s (t); S3, projecting output of the vibration velocity sensor in a formula of the step S2 to a certain observation direction to obtain a synthetic vibration velocity expression of the received signals; S4, multiplying a sound pressure matrix with a synthetic vibration velocity matrix to obtain a sound pressure and vibration velocity cross covariance matrix; S5, performing Unitary transformation for the cross covariance matrix to generate a matrix R'=PHRfbP; S6, performing eigenvalue decomposition for the matrix R' after Unitary transformation to obtain an equivalent noise subspace Un'=PUn; S7, generating a polynomial F (z)=zM-1QT (1 / z) (Un') (Un') HQ (z) by the equivalent noise subspace, extracting the root of the F (z) and identifying the generated root to obtain a direction-of-arrival angle. By the aid of the technical scheme, detection complexity is reduced, and detection precision is improved.

The invention discloses a GNSS passive radar air moving target remote sensing detection method and system, and the method comprises the steps: employing a GNSS signal as a signal source, and employing a bistatic radar model as a signal receiving model; signals emitted by several satellites are received at the same time through the same receiver, and noise cancellation is carried out on the signals by using the self-correlation characteristic of GNSS codes; and generating RDM by using the denoised signal, estimating the carrier phase of the air moving target, and resolving to obtain the motion state information. According to the invention, the accuracy of estimating the Doppler frequency of the moving target by the RDM is improved.

A method for preparing a vehicle-mounted RFID electronic tag, comprising the following steps: (1) adding a radio frequency amplifier outside the RFID receiver, and using a microstrip line to perform impedance matching on the input end and the output end in order to reduce reflection; An external antenna is added to the outside of the receiver, and the antenna adopts a specific light and small four-arm helical antenna; (3) The baseband digital signal of the receiver is oversampled and filtered, and the data obtained by oversampling can be extracted with a CIC filter to increase the data rate. Return to the normal level, then cascade the FIR filter for band-pass filtering, further reduce the noise power and improve the signal-to-noise ratio; (4) Perform DC offset correction processing on the receiver baseband digital signal, and filter the signal through capacitive AC coupling The DC part is used to reduce the interference of the DC offset; (5) Perform coherent detection data decoding processing on the receiver baseband digital signal.

The invention discloses an LTE downlink channel estimation method suitable for a complex environment, which can solve the problems of accuracy and efficiency of LTE downlink channel estimation in thecomplex environment. The LTE downlink channel estimation method suitable for the complex environment comprises the steps of A, preliminary estimation of a pilot channel; B, small-range smoothing of pilot frequency estimation; and C, two-dimensional linear interpolation. By adopting the LTE downlink channel estimation method suitable for the complex environment, accurate channel estimation and noise suppression can be realized; and efficient estimation can be achieved, and fast channel change conditions can be adapted.

The invention provides an improved compressor. The compressor comprises a shell, an opening, an inlet pipe, a silencer pipe and a silencer, wherein one end of the silencer pipe is leaded to the silencer, and the other end penetrates through the opening on the shell to extend outside the shell, and is leaded into the inlet pipe; and the end part of the inlet pipe is connected to the opening to form a gap therebetween. The improved compressor prevents most of refrigerant fluids received into the silencer through the shell. Therefore, the temperature of the refrigerant fluids entering the silencer is kept lower to improve the compressor efficiency. In addition, as the silencer pipe and the inlet pipe are not contacted with each other, the vibration and the noise caused by the vibration are prevented.

The flywheel of all internal combustion engine comprises a support and a ring gear. The outer peripheral end of the support has a radial surface and the inner peripheral end of the ring gear has a complementary radial surface. An element of viscoelastic material is situated between the radial surface and the complementary radial surface in such a manner as to put under compression stress in the radial and axial directions.

The invention discloses a device for improving the temperature resolution of a long-distance BOTDR system by using distributed Raman amplification and EDFA technology. And the comparison chart of temperature resolution obtained by using this method and conventional method. The device of the invention can improve the temperature resolution of the long-distance BOTDR system.

Receiving sensitivity deterioration in wireless communication due to a spurious radiation wave generated from a card reader writer is suppressed, in the case where a noncontact IC card reader writer or a noncontact IC card is mounted in a cellular phone terminal. The cellular phone terminal provided with the noncontact IC card reader writer performs measurement of a wireless status upon reception (step S1) and transmission power setting (step S2), and when an instruction to start a reader writer function is inputted from a user (step S3), wireless status deterioration due to spurious radiation from the reader writer is predicted (step S4). Then, the cellular phone terminal judges whether control to reduce the transmission speed is necessary or not, based on a value of the deterioration predicted wireless status (step S5), and when judged necessary, the transmission speed is reduced (step S6).

The invention provides a method for improving the noise of an idle audio channel, which is applied to an audio receiving system of a mobile phone. The method comprises the following steps: generatingan audio signal; and inputting the audio signal to a Sigma-Delta modulator for noise reshaping so as to remove the noise in the audio signal out of a preset tested frequency band. The method can reduce the noise power of the tested frequency band in the audio receiving system of the mobile phone, so the audio receiving system of the mobile phone is endowed with a signal to noise ratio meeting therequirement of a protocol 3GPP TS 26.131. The invention also provides the audio receiving system of the mobile phone.

The invention provides a digital decimation filter. The digital decimation filter comprises a cascade integral comb filter, a cascaded Lagrange half-band filter and an FIR filter, which are orderly connected. The digital decimation filter has the advantages of less pass band dropping, small quantized noise power after filtering, and less power consumption.

The invention discloses an LTE downlink channel estimation method suitable for complex environments, which can solve the accuracy and high efficiency problems of LTE downlink channel estimation in complex environments. The LTE downlink channel estimation method suitable for complex environments includes steps A, preliminary estimation of the pilot channel; B, small-scale smoothing of pilot channel estimation; C, two-dimensional linear interpolation; adopting the LTE downlink channel estimation suitable for complex environments The method can realize accurate channel estimation and noise suppression; at the same time, it can realize high-efficiency estimation and can adapt to fast channel changes.

The invention discloses a two-way multi-order related detection method for a dual-polarization weather radar. The method comprises the following steps: obtaining I / Q (in-phase / quadrature) data of an H (horizontal) channel and a V (vertical) channel; calculating the coherent integration quantities of the H channel and the V channel; calculating the zero-order self-correlation, first-order self-correlation and zero-order cross-correlation quantities of the H channels and the V channels; calculating the weight sum of the multi-order correlation quantity; comparing the weight sum with a threshold value, judging if a weather echo is generated, and if so, calculating the signal-to-noise ratio of the H channel; calculating reflectivity factors under different signal-to-noise ratios; and controlling the quality according to the reflectivity factors, and outputting results. According to the method, the weight sum of the multi-order correlation quantity is introduced in combination with horizontal and vertical polarization echo signals to change a conventional method which simply takes the signal-to-noise ratio of the H channel as a detection factor so as to achieve the purposes of reducing the background noise power and increasing the weak signal detection level, and reduce the loss of the signal-to-noise ratio of an echo wave in a double-transceiver mode.