1251 results about "Filter (signal processing)" patented technology

A method for reducing interference, comprising receiving a wideband signal, having at least one large amplitude component; adaptively modifying the wideband signal with respect to at least one high intensity component without substantial introduction of non-linear distortion, while reducing a residual dynamic range thereof; digitizing the modified wideband signal to capture information describing at least the high intensity signal at a sampling rate sufficient to extract modulated information present within the wideband signal at an upper limit of the band. The system analyzes a spectral characteristic of the wideband signal; and extracts adaptation parameters for the adaptive filtering. The system therefore provides both large net dynamic range and wideband operation. Preferably, the digitizer and filter, and part of the spectral characteristic analyzer is implemented in using superconducting circuit technology, with, for example low temperature superconducting digital signal processing components, and high temperature superconducting analog filtering components.

In order to utilize several radio communication systems with a radio terminal 1, by preparing the common modulator and demodulator part 2a and reconfigurable modulator and demodulator part 2b in advance and performing function selection means 4 with specified means of differential information 5 which information consists of the list of differential specification information of each radio communication system such as the tap coefficients of filter, frame format and the like, and their hardware address to allocate the information into digital signal processing hardware, the required radio communication systems are realized as users like.

A signal processing system includes an analog-to-digital delta sigma modulator with a duty cycle modulator and a finite impulse response (FIR) filter in a main loop feedback path of the delta sigma modulator. The duty cycle modulator and FIR filter can provide high performance filtering in the main loop feedback path. To prevent instability in the main loop caused by the duty cycle modulator and FIR filter, the delta sigma modulator also includes a stabilizer loop. Transfer functions of the main loop and the stabilizer loop combine to achieve a target transfer function for the analog-to-digital delta sigma modulator that provides for stable operation of the analog-to-digital delta sigma modulator.

A signal processing method including the steps of: receiving a first audio signal; detecting the presence of one or more shrieks within an audible frequency range of said audio signal; creating one or more filters to selectively attenuate the respective one or more shrieks within the audible frequency range; filtering the audio signal using the one or more filters; and transmitting the filtered audio signal to an audio telephone device.

A switched filter signal processing system includes an input terminal for receiving an input signal conveying first signal information in a first time phase and second signal information in a different second time phase. Desired information represents the difference between the first and second signal information. A multiplexed switch filter filters the input signal in the first phase with a first filter to obtain the first signal information and filters the input signal in the different second time phase with a second filter to obtain the second signal information. The system also includes a common filter component, which is shared by the first and second filter, and respective second filter components for the first and second filters. A controller controls the multiplexed switch filter to couple the common filter component to the second filter component of said first filter in said first time phase and to couple the common filter component to the second filter component of the second filter in the second time phase.

Methods and apparatus provide for positioning of a rover antenna from GNSS data derived from multi-frequency signals and correction data derived from a network of reference stations. Rover antenna position and multi-frequency ambiguities are estimated at each epoch. An ionospheric filter models variation in ionospheric bias per satellite. A set of ionospheric carrier-phase ambiguities is estimated at least when the multi-frequency ambiguities have attained a predetermined precision. The estimated ionospheric carrier-phase ambiguities are cached. After detecting interruption of signal at the rover antenna and determining reacquisition of signals at the rover antenna, an ionospheric bias per satellite over an interruption interval is predicted. For each satellite, a cached ionospheric carrier-phase ambiguity is combined with a predicted ionospheric bias to obtain a post-interruption ionospheric ambiguity estimate. The post-interruption ionospheric ambiguity estimates are used to aid estimation of rover antenna position after signal reacquisition.

The invention discloses a radar signal parallel processing method and system based on a heterogeneous multinucleated system. The method comprises the following steps: S1, initializing equipment-end parameters, opening up a task execution thread, and dividing thread grids of data processing and the dimensions of a thread block; S2, opening up a video memory space and a memory space which are needed for the signal processing; S3, acquiring data transmission and calculating time needed by signal processing of a single time, and scheduling a genetic task scheduling algorithm to obtain a task scheduling mode; and S4, acquiring laser sampling data for storing in the memory space by means of segments according to a time sequence, sending the data to a CPU and a GPU according to the task scheduling mode, mapping sampling points to each thread and performing concurrent execution according to the thread grids and the dimensions of the thread block, and scheduling a filter coefficient to perform orthogonal phase demodulation, pulse compression, moving object display, moving object detection, pulse accumulation and constant false alarm detection on the sampling data. By applying the method and system provided by the invention, the speed of a general processor in executing the signal processing is improved, and the requirement for real-time performance of radar signal processing is met.

The invention relates to a full-distributed optical fiber strain and vibration sensor based on coherent heterodyne detection, which comprises a laser (1), a coupler, a pulse modulation module, a programming gain amplifier (4), an optical amplifier, a circulator (6), a sensing fiber (7), a polarization-preserving fiber (8), the coupler, a balancing photoelectric detector (10), a reversal switch, a mixer, a microwave source, a band-pass filter, and a signal processing unit, wherein the continuous light output by the laser (1) is divided into two paths after passing through the coupler (2); an output end of the balancing photoelectric detector is connected to the reversal switch; the reversal switch is switched to a channel 1 and a channel 2; when the channel 1 is switched on, the system utilizes the Brillouin optical fiber time domain reflection to measure; and when the programming gain amplifier (4) is closed and the channel 2 is switched on, the system utilizes the polarization optical time-domain reflection to measure. By using the full-distributed optical fiber strain and vibration sensor provided by the invention, the full-distributed measurement for strain as well as the weak vibration and the full-distributed measurement for vibration can be performed on a single optical fiber.

The present invention relates to improved multiple access communications. In one form, the invention relates to an improved signal processing method and apparatus for an iterative method of determining the reception of a signal in a multi user packet based wireless OFDM (Orthogonal Frequency Division Multiplexing) communication system. In other forms the present invention provides recursive filtering for joint iterative decoding in a variety of systems and functions such as linear multiple access channel decoders, iterative equalisation, iterative joint channel estimation and detection / decoding, iterative space-time processing, iterative multi user interference cancellation and iterative demodulation. In one particular form the present invention provides an iterative decoding circuit for a wireless multiuser communications receiver comprising a first signal processing means for receiving at least one received signal, said first signal processing means comprising at least two linear iterative filters such that the first linear iterative filter provides an estimate of a selected received signal to an estimated signal output and a second linear iterative filter provides estimates of at least one other received signal, delayed by one iteration cycle, to an input of said first linear iterative filter, a second signal processing means for receiving the estimated signal output of the first linear iterative filter and providing a further received signal estimate to the input of the first signal processing means in a succeeding iteration cycle of the decoding circuit.

The invention provides a multi-carrier digital frequency-selecting remote system, which comprises a digital access control unit DAU and a digital radio remote unit DRU, wherein the digital access control unit DAU is connected with the digital radio remote unit DRU through optical fiber; the digital access control unit DAU comprises a DAU duplexer, a DAU downlink, a DAU photoelectric conversion subsystem, a DAU uplink, a DAU power subsystem and a DAU monitoring subsystem; the digital radio remote unit DRU comprises a DRU photoelectric conversion subsystem, a DRU downlink, a DRU duplexer and a DRU uplink; and the DRU monitoring subsystem and the DRU power subsystem are connected with the DRU uplink and the DRU downlink respectively. The system replaces a surface filter SAW with a digital intermediate-frequency processing technique in software radio, so as to keep a hardware platform unchanged, reduce the application of analog devices and guarantee the consistency of system performances while the number of carriers is increased / decreased at will.

A signal processing system includes an analog-to-digital delta sigma modulator with a duty cycle modulator and a finite impulse response (FIR) filter in a main loop feedback path of the delta sigma modulator. The duty cycle modulator and FIR filter can provide high performance filtering in the main loop feedback path. To prevent instability in the main loop caused by the duty cycle modulator and FIR filter, the delta sigma modulator also includes a stabilizer loop. Transfer functions of the main loop and the stabilizer loop combine to achieve a target transfer function for the analog-to-digital delta sigma modulator that provides for stable operation of the analog-to-digital delta sigma modulator. In at least one embodiment, the stabilizer loop includes a stabilizer path that provides output data directly to an integrator of the main loop filter.

The invention discloses a multi-mode multi-frequency global navigational satellite system receiver radio frequency front end device. The device comprises a low-noise amplifier, a power divider, and multiple radio-frequency signal processing circuits, wherein the low-noise amplifier, the power divider, and the multiple radio-frequency signal processing circuits are connected in sequence. Each radio-frequency signal processing circuit comprises a first radio-frequency switch, a radio-frequency filter bank, a second radio-frequency switch, a radio-frequency amplifying module, a lower frequency mixing module, an intermediate frequency filter module, an intermediate frequency amplifying module, and an automatic gain control unit, wherein the first radio-frequency switch, the radio-frequency filter bank, the second radio-frequency switch, the radio-frequency amplifying module, the lower frequency mixing device, the intermediate frequency filter module, the intermediate frequency amplifying module, and the automatic gain control unit are connected in sequence. The lower frequency mixing module comprises a lower frequency mixing device and a local oscillating generating module which are connected with each other. A control unit is connected with the first radio-frequency switch and the second radio-frequency switch of each radio-frequency signal processing circuit and the local oscillating generating module of the lower frequency mixing module. The device can flexibly select intermediate frequency inputting from various combination frequency ranges of a quad-mode 11 frequency range, and therefore functions of collecting in the same module and processing navigation system intermediate frequency signals of four system satellites are realized, namely a global position system (GPS), Glonass, Galileo, and Big Dipper.

The invention discloses a digital audio directional loudspeaker and a digital audio signal processing method. An automatic gain control module adjusts the amplitude of a sound source signal; then, a filter filters out elements beyond a audio signal belt so as to reduce noises; a signal input module changes an audio analog signal into a digital signal; the processing of approximate square root algorithm or other algorithms to the audio digital signal is finished in the digital signal processing module; two state levels are output into a switch type power amplifier to match with the network to assure impedance matching; an ultrasonic transducer is used for changing an electric signal into a sound pressure signal. The ultrasonic signal which is emitted from the transducer carries the input audio signal information, does the nonlinear interaction in the air and is demodulated into audible sound. A remote control receiving unit receives orders sent by a remote control transmission unit to control parameters such as point angle, volume, transmission distance, sound effect and point sound, etc.

Signal processing architectures for direct acquisition of spread spectrum signals using long codes. Techniques are described for achieving a high of parallelism, employing code matched filter banks and other hardware sharing. In one embodiment, upper and lower sidebands are treated as two independent signals with identical spreading codes. Cross-correlators, in preferred embodiments, are comprised of a one or more banks of CMFs for computing parallel short-time correlations (STCs) of received signal samples and replica code sequence samples, and a means for calculating the cross-correlation values utilizing discrete-time Fourier analysis of the computed STCs. One or more intermediate quantizers may optionally be disposed between the bank of code matched filters and the cross-correlation calculation means for reducing word-sizes of the STCs prior to Fourier analysis. The techniques described may be used with BOC modulated signals or with any signal having at least two distinct sidebands.

Systems and methods for audio signal processing are disclosed, where a discrete number of simple digital filters are generated for particular portions of an audio frequency range. Studies have shown that certain frequency ranges are particularly important for human ears' location-discriminating capability, while other ranges are generally ignored. Head-Related Transfer Functions (HRTFs) are examples response functions that characterize how ears perceive sound positioned at different locations. By selecting one or more “location-critical” portions of such response functions, one can construct simple filters that can be used to simulate hearing where location-discriminating capability is substantially maintained. Because the filters can be simple, they can be implemented in devices having limited computing power and resources to provide location-discrimination responses that form the basis for many desirable audio effects.

The invention provides a position observation device and a position observation method for a rotor of a built-in permanent magnetic synchronous motor based on adaptive filtering, and belongs to the field of motor control, solving the problem of the convectional model method that six-time harmonic pulsation observation error is contained in the acquired rotor position angle observation value. The position observation device and the position observation method are respectively an adaptive notch filtering filter signal processing device and an adaptive notch filtering filter signal processing method based on the least mean square algorithm, and the device and the method are used for removing the six-time rotor pulsation error in the control technology model method applicable to a middle and high speed position-free sensor permanent magnetic synchronous motor. The method comprises the following steps of: acquiring equivalent back electromotive force information through the model method; regulating through the adaptive notch filtering filter based on the least mean square algorithm; then carrying out normalization processing on the back electromotive force information; and finally acquiring a rotor position observation value through a phase-locked loop. The device and the method provided by the invention are simple and easy to implement, can be used for effectively inhibiting the influence of the six-time pulsation error in the rotor position observation value and improving the performance of the position-free sensor permanent magnetic synchronous motor, and are applicable to a permanent magnetic synchronous motor control system.

An interference canceller between a transmit chain and a receive chain of a transceiver is proposed to complement the action of a diplexer, or duplex filter, that is part of the transceiver. The interference canceller comprises a transmit chain tap, a receive chain coupler for coupling an interference compensation signal into the receive chain, and an interference signal processing path between the transmit chain tap and the receive chain coupler. The interference signal processing path comprises a filter having filtering characteristics similar or corresponding to the filtering characteristic of a receive portion of said diplexer. A corresponding method for interference cancellation is also proposed. Computer-program products for the manufacture of the interference canceller and the execution of the method are also proposed.

The invention relates to a signal reconstruction technical scheme for sampling with rate lower than nyquist rate. The signal reconstruction scheme comprises the following steps of: firstly, solving a transformation basic matrix (signals x to be reconstructed thereon are sparse on the transformation basic matrix), modulating the transformation basic matrix with a cutting sequence, filtering by means of a digital filter, sampling the filtered signals, then generating compressive sensing arithmetic operators, and finally obtaining reconstructed signals by solving an optimized problem through the sparse inverse transformation. The invention aims to provide the signal reconstruction technical scheme for sampling with rate lower than the Nyquist rate, satisfy the needs for people in solving the contradictions between the increasingly widening signal bandwidth as well as the increasingly quickening sampling frequency and the requirements for reducing processing time and various costs reduce the signal sampling frequency and data transmission and storage cost, further remarkably shorten the signal processing time and reduce the computational expense, and accurately reconstruct signals.

A directional signal processing system for beamforming information signals. The system includes an oversampled filterbank, which has an analysis filterbank for transforming the information signals in time domain into channel signals in transform domain, a synthesis filterbank and a signal processor. The signal processor processes the outputs of the analysis filterbank for beamforming the information signals. The synthesis filterbank transforms the outputs of the signal processor to a single information signal in time domain.

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

A video signal processing apparatus and a video signal processing method are capable of outputting a display having a high picture quality by effectively utilizing an output resolution. A microcomputer controls a shrinkage filter, a memory and an enlargement filter to carry out a resolution conversion process of converting the signal format of a video signal into a selected output signal format depending on the output format setting of a D terminal of the video processing apparatus, and outputs the video signal.

A polar receiver using injection-locking technique includes an antenna, a first filter, a first voltage-controlled oscillator, a first mixer, a frequency discriminator, a second filter, a third filter, a first analog-digital converter, a second analog-digital converter and a digital signal processing unit. Mentioned polar receiver enables to separate an envelope signal and a frequency-modulated signal from a radio frequency signal received from the antenna via the injection locking technique of the first voltage-controlled oscillator and the frequency discriminator. The envelope component and the frequency-modulated component can be digitally processed by the digital signal processing unit to accomplish polar demodulation.

The invention discloses a distributed fiber sound wave detection apparatus and method based on wave beam formation. The apparatus comprises a light source, a 1*2 coupler, a control and signal processing unit, an arbitrary waveform generator, a double-channel parallel Mach-Zehnder electro-optical modulator, a reference arm fiber, an erbium doped fiber amplifier, an optical filter, an annular device, a front-end reflector, a reference length fiber, a rear-end reflector, a sense fiber, a 90-degree optical mixer, and a balance detector. The method includes the steps: injecting signal light into the sense fiber, the signal light being modulated to be light pulses with a fixed frequency on a lower side and a sweep frequency on an upper side; mixing the returned signal light carrying light phase information and light frequency spectrum information of detecting points with local reference light; demodulating the light phase information and the light frequency spectrum information, and obtaining the frequency, amplitude and phase information of sound waves in the detecting points in the sense fiber; and finally calculating the position, intensity and frequency information of sound sources. The sensing function and the transmission function of a fiber are combined into one function. Therefore, the distributed fiber sound wave detection apparatus and method have the advantages that the detecting point scale is hundred times higher than that of the prior art.

A vector slot processor that is capable of supporting multiple signal processing operations for multiple demodulation standards is provided. The vector slot processor includes a plurality of micro execution slot (MES) that performs the multiple signal processing operations on the high speed streaming inputs. Each of the MES includes one or more n-way signal registers that receive the high speed streaming inputs, one or more n-way coefficient registers that store filter coefficients for the multiple signal processing, and one or more n-way Multiply and Accumulate (MAC) units that receive the high speed streaming inputs from the one or more n-way signal registers and filter coefficients from one or more n-way coefficient registers. The one or more n-way MAC units perform a vertical MAC operation and a horizontal multiply and add operation on the high speed streaming inputs.

A digital-to-analog converter (“DAC”) system utilizes chopping modulation technology to remove 1 / f and other baseband noise from a baseband of a signal of interest. Chopping modulation and demodulation circuitry of the DAC operate at a chopping frequency equal to approximately one-half of a digital input signal sampling frequency. Chopping at one-half the sampling frequency allows fold back into the baseband of the input signal's frequency components and reduces fold back of noise, such as quantization noise, residing outside the baseband. In a further embodiment, a notch filter attenuates signals having frequencies around the chopping frequency prior to chopping to reduce fold back of noise into the baseband due to parasitic modulation. Coordination of chopping timing also reduces noises in the output of the DAC system.

Methods and apparatus for applications such as signal processing, analysis, and coding / decoding replace digital signal processing elements with analog components. By combining soft logic gates and filters, the functionality of complex finite state machines can be implemented.

The invention discloses a method for compensating delay and frequency response characteristics of multi-output channel sound system and system implementation thereof. The method comprises the following steps that firstly, phase difference between channels of a multi-channel output device is measured, so that the situation that the multi-channel output device itself is in the state of synchronously outputting signals is ensured; then the delay of the signals which are output by the multi-channel output device and pass through a signal processing system, a loudspeaker box and a space transmission routine to reach a specific audition area is estimated through a delay estimation method, and delay compensation is conducted on the channels by comparing delay difference between the channels; finally, an FIR frequency response compensating filter is designed and achieved according to actually detected frequency response curves of a signal transmission routine, and the part above the low and medium frequency in the frequency response curves of the multiple channels is compensated into a straight line through the filter as far as possible. By means of the method, when sound waves transmitted out of each loudspeaker box reach the audition area, the phases of the sound waves are basically the same, and the frequency response characteristics of the channels are basically the same.

The invention discloses a dual-wavelength superheterodyne-interference wide-range high-precision real-time displacement measuring system and method. The system is composed of two lasers between which the wavelength difference is deltalambda, three polarization splitting prisms, four splitting prisms, two acousto-optic modulators, four 1 / 4 waveplates, five planar mirrors, three Polaroids, a super-narrowband filter plate, two large-bandwidth transimpedance photoelectric detectors, two low-bandwidth high-sensitivity photoelectric detectors, a reference reflector, a measured reflector, a signal processing circuit and a host computer. According to the invention, a synthesized wavelength interference signal generated by dual wavelengths is used to improve the measuring range of the system, so that the measuring range of the system is greater than the range of single-wavelength interference; a superheterodyne interference method is used to demodulate and filter output signals, the phase of the synthesis wavelength can be measured directly, and real-time measurement is realized; and the super-narrowband filter plate is used to collect single-wavelength interference signals, and the precision of single-wavelength interference measurement is ensured while the measuring range is widened.

The invention discloses a software radio-based ultra-wideband digital satellite beacon receiving method and a receiver. The receiver comprises an ultra-wideband radio frequency front end and a digitalsignal processing module, whose signals are mutually communicated, and a power supply module for providing power for the ultra-wideband radio frequency front end and the digital signal processing module, wherein the ultra-wideband radio frequency front end includes a variable gain amplifier, a quadrature mixer, a local oscillator, an I-channel amplifier, an I-channel filter, an I-channel ADC, anda Q-channel amplifier, a Q-channel filter and a Q-channel ADC; the digital signal processing module includes a frequency calculation module, a power calculation module, and a control interface module. According to the method and the receiver, a digital signal processing method, and self-adaptive frequency adjustment and gain adjustment are used for carrying out precise frequency and power calculation on a satellite beacon signal, and outputting frequency and power information to an antenna controller to form an antenna turntable driving command to complete the alignment satellite process. Themethod and the receiver have the advanteges of ultra-wideband operation, large dynamic range, high integration, stable and reliable performance, strong universality and the like.

The invention provides a static pressure balanced fiber ultrasonic sensor array measuring system which comprises an extrinsic Fabry-Perot fiber ultrasonic sensor, a light source module, a wavelength division multiplexer, a tunable narrow-band optical filter, and a photoelectric detection and signal processing unit. The light source module is connected with a first port of the wavelength division multiplexer; a third port of the wavelength division multiplexer is connected with the fiber sensor by a transmission fiber; other output ports of the wavelength division multiplexer are respectively connected with different fiber sensors; therefore, light beams with different wavelength ranges respectively act on the different fiber sensors, simultaneously, a plurality of different interfered light beams reach a first port of the tunable narrow-band optical filter by a second port of the wavelength division multiplexer; and a second port of the tunable narrow-band optical filter outputs a narrow-band light to a photoelectric detection tube which converts optical signals into electric current signals and sends the electric signals into the signal processing unit. The static pressure balanced fiber ultrasonic sensor array has the beneficial effects of being capable of automatically eliminating the deviation of the working point of the sensor caused by static state pressure variation and temperature change and increasing the wavelength division multiplexing capability of the measuring system.