1199 results about "Filter (signal processing)" patented technology

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.

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.

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.

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 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.

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.

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 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.

The invention discloses a distributed optical fiber vibration sensing system based on polarization beam splitting detection and a sensing method. The distributed optical fiber vibration sensing system comprises an induction system and a detection control system, wherein the induction system is used for inducing external vibration events and comprises a light source, a pulse modulator, a circulator, a polarization beam splitter, a first amplifier, a second amplifier, a first filter and a second filter; and the detection control system is used for detecting and controlling vibration signals and comprises a first detector, a second detector, a collector and a data processor, wherein the data processor is used for processing an output signal of the collector and analyzing the processed signal to select if giving an alarm. The distributed optical fiber vibration sensing system based on polarization beam splitting detection and the sending method is sensitive to the vibration signals, high detection precision and great high space resolution ratio; and in addition, compared with the prior art, the distributed optical fiber vibration sensing system has simple structure and convenient signal processing.

The invention belongs to the radar technology field and signal processing field and more particularly, to a tensor-sparse-representation-based MIMO radar's imaging method for a multi-input and multi-output type system. The method comprises: transmitting by M emission array elements mutually orthogonal phase coded signals; receiving by N receiving array elements the phase coded signals; using a matched filter to perform matched filtering to the received radar signals; conducting the Fourier transform to the signals after matched filtering to obtain the spatial spectral echo expression; performing mesh generation to the scene; and discretizing the radar echoes to obtain the mathematical expression for radar imaging and focusing under the compression sensing framework. The method of the invention overcomes the shortcoming of a DAS method which has intrinsically low resolutions and high side lobes. Compared with other classic imaging method featuring compression sensing, the THMP method of the invention fully utilizes the tensor characteristics of received signals to conduct sparse signal recovery, which avoids the information loss of the internal structure of the signals brought about by the vectorized operations.