532 results about "Comb filter" patented technology

A DTV signal has a plural-data-segment frame header including complementary first and second ghost-cancellation reference signals differentially delayed by the duration of two NTSC horizontal scan lines. A receiver for such DTV signal has an adaptive equalizer for baseband symbol code with kernel weights calculated by a computer operative on the equalizer response after comb filtering. The comb filter combines the equalizer response as differentially delayed by the duration of two NTSC horizontal scan lines to cancel artifacts of co-channel NTSC interference in the comb filtered equalizer response supplied to the computer. This reduces the undesirable influence of such artifacts on equalization to reduce intersymbol interference.

In a physiological monitor, a method and an apparatus for determining a patient's pulse rate using data corresponding to a plurality of wavelengths of electromagnetic energy transmitted through the tissue of the patient. The method includes tracking the pulse rate in the data using an adaptive comb filter, the data having signal portions corresponding to the pulse rate and signal portions corresponding to noise, periodically calculating a frequency power spectrum of one of the wavelengths, and using the frequency power spectrum in a pulse rate calculator to determine the pulse rate or to verify the pulse rate calculated by the pulse rate calculator.

The subject invention pertains to a frequency modulation continuous wave (FMCW) radar system. Embodiments relate to methods of improving the performance of such a FMCW system and improving the value of the information provided by such a FMCW system. In an embodiment of the subject invention, the IF level can be monitored while sweeping the frequency of the system through at least a portion of the frequency range of the system. In a specific embodiment, the system is then set to the frequency that produces the minimum IF level, which is the frequency that produces the minimum AM signal level. Embodiments of the invention pertain to techniques for expediting the adaptation of the comb filter to the signal when the system is turned on. In an embodiment, in order to reduce the number of detection calculations a processor performs every frame, a method of quickly determining the largest peaks in the RDM is implemented. Embodiments of the subject invention relate to a method for processing a radar signal that classifies two or more targets. A specific embodiment of a method for processing the radar signal classifies a human target or other target(s) using amplitude values in time-consecutive range-Doppler maps. Embodiments of the invention pertain to a method for processing a radar signal for improving the performance of FMCW detection, tracking, and classification algorithms. Embodiments improve such performance by increasing the SNR and velocity measurement resolution of slow moving targets while minimizing DSP computational and memory requirements in two-dimensional FFT range-velocity processing.

Embodiments pertain to methods of improving the performance of a frequency modulation continuous wave (FMCW) radar system and improving the value of the information provided the FMCW system. In an embodiment, the IF level is monitored while sweeping the frequency of the system through at least a portion of the frequency range of the system and the frequency is set to produce the minimum IF level. Embodiments expedite the adaptation of the comb filter to the signal when the system is turned on. In an embodiment, a method of quickly determining the largest peaks in the RDM is implemented. Embodiments relate to a method for processing a radar signal that classifies two or more targets. An embodiment classifies a human target or other target(s) using amplitude values in time-consecutive range-Doppler maps. An embodiment processes a radar signal for improving the performance of FMCW detection, tracking, and classification algorithms.

A tunable optical system with hybrid integrated semiconductor laser is provided. The optical system includes a silicon-on-insulator (SOI) substrate; a first optical waveguide tunable comb filter formed at the first side of the SOI substrate; a second optical waveguide tunable comb filter with detuned filter response formed at the first side of the SOI substrate; an etched laser pit at the first side of the SOI substrate; a plurality of spacers formed on the bottom surface of the laser pit near the plane of the first side of the SOI substrate; a plurality of bumping pads formed on the bottom surface of the laser pit near the plane of the first side of the SOI substrate; and a laser chip flip-chip bonded at the first side of the SOI substrate supported by the spacers. Heating sections may be provided on the filters to tune the filters.

The invention discloses an all digital frequency converting method and a device thereof, being easily realized for hardware. The method and the device are essentially used for sample rate convertion of rational number-times of baseband signals and the convertion of the baseband signals and the intermediate frequency signals in digital communication. Under the coordination of control signals and enabling signals, the convertion of signal sample rate can be finished and the convertion of the baseband signals and the intermediate signals can be finished through the reasonable matching of variable integral number-times wave filtering and fraction-times interpolation. The system of the invention essentially comprises a frequency mixer, a cascade connection integral comb filter, a fraction-time interpolating device, a half-band filter, a signal shaping filter, a power detection module and a control interface. The configurable hardware implemented structure of the invention is applicable to a plurality of modulation methods, has the advantages of low resource consumption and good portability, and is used for various wireless communication systems such as multilevel phase shift keying (MPSK), orthogonal frequency division multiplex (OFDM), direct sequence spread spectrum (DSSS) and continuous phase modulation (CPM), etc.

A microphone assembly includes one or more transducers (2210) that are positioned in one or more housings. A preprocessing circuit (2215) includes a inverted comb filter (2245) for eliminating predetermined frequencies between harmonics of the human voice in a predetermined frequency range. A processing circuit (2220) coupled to the preprocessing circuit (2215) is used for outputting an electrical signal such that the transducers (2210) used in combination with the processing circuit (2220) very effectively cancels noise. The microphone assembly can be employed in a vehicle accessory such as a vehicular mirror.

The invention discloses a microwave frequency measuring method based on optical power detection and a device thereof, which conducts real-time measurement on microwave frequency by adopting a system consisting of an electro-optical modulating module and a frequency demodulating module. A continuous microwave signal is loaded on a continuous light source in the modulating module in the modulating manner of carrier suppressed small signals, and only generates two plus or minus 1 stage optical margin strips; the modulated optical signal is divided into two paths, wherein one path is injected into a comb-like filter with sine-function transmission spectrum while the other path is injected into a tunable optical attenuator; the output optical power of the two paths are detected and compared with each other and the microwave frequency is obtained from the demodulation of power ratio. The invention lowers the complexity and cost of the system, eliminates the influence of fluctuation of output power of the light source on the measurement of the frequency and enlarges the measuring frequency band of frequency linear demodulation.

A method for reducing phase differences varying with frequency occurring at certain listening positions with respect to loudspeakers reproducing respective ones of multiple sound channels in a listening space, the phase differences occurring in a sequence of frequency bands in which the phase differences alternate between being predominantly in-phase and predominantly out-of-phase, comprises adjusting the phase in multiple frequency bands in which the multiple sound channels are out-of-phase at such listening positions. Such adjustment of phase includes the frequency bands in which the width of comb filtering pass bands and notches resulting from phase differences at such listening positions would be greater than or commensurate with the critical band width if the phase adjustment were not applied. The listening space may be the interior of a vehicle.

A speech processing apparatus and method may identify divisions of a signal spectrum as having a speech component or having no speech component. A comb filter is generated, based on a high-accuracy speech pitch obtained in the identified speech component divisions, for enhancing speech information in the speech component divisions. The comb filter is applied to the speech component divisions to suppress noise.

A waveform compression and display technique saves both a peak detected version (background version) and a decimated / lowpass filtered version (foreground version) of a sampled electrical signal. The two versions are displayed simultaneously overlaid together in a contrasting manner so as not to obscure information contained in either of them. The lowpass filtered version uses a series of simple lowpass filters with decimation to produce a single data stream from a plurality of data streams derived from the sampled electrical signal. The single data stream may then be subjected to additional filtering, such as a cascaded integrator-comb filter, to obtain a desired frequency bandwidth. When displayed, the peak detect pixels adjacent the decimated / lowpass filtered pixels may be adjusted in intensity so that the low frequency information of the lowpass filtered waveform is not lost, while the peak detect pixels further from the lowpass filtered pixels are intensified to highlight the high frequency information. Alternatively the background version intensity may be controlled by a user control over a first range from zero to a predetermined maximum, and the foreground version may be controlled over a second range from a default intensity to a maximum, saturated intensity.

A nonperiodic waveform is forced to a periodic character to facilitate looping of the waveform without introducing audible, and thus objectionable, sound artifacts. Nonperiodic waveforms are typically nonperiodic due to the presence of nonharmonic high frequency spectral components. In time, the high frequency components decay faster than low frequency components and looping of the waveform is facilitated. A loop forcing process and loop forcing filter facilitate looping of a nonperiodic waveform by accelerating the removal of the nonperiodic high frequency components. A loop forcing filter accelerates the removal of nonperiodic high frequency components using a comb filter having a frequency selectivity that varies in time.

The invention relates to an erbium doped fiber laser with multi-wavelength and mode locking functions and convertible working state and a realization method thereof, in particular to a laser which can realize switching conversion between multi-wavelength and mode locking, has adjustable output wavelength position of multi-wavelength, and can stably work at room temperature and a realization method thereof. The laser comprises: a gain amplification unit, a polarization control unit, an output coupling unit, a comb filtering unit, an optical isolation unit and a nonlinear fiber loop mirror. The realization method of the laser includes the following steps: incident polarization state and double refraction are adjusted to lead the nonlinear fiber loop mirror inserted in the cavity of the laser to be in different working states, and the multi-wavelength and mode locking functions of the laser are respectively realized according to the different working conditions of the nonlinear fiber loop mirror. The invention has the advantages of convenient toning, low cost, being capable of realizing the two functions of stable multi-wavelength continuous output and mode locking pulse output, and the like, and can satisfy the demand for multifunctional laser light sources of optical time division multiplex / wavelength division multiplex communication technology.

The invention relates to a magnetic control tunable optical fiber comb filter belonging to the technical fields of optical fiber sensing and optical fiber communication. The magnetic control tunable optical fiber comb filter comprises a broadband light source, an optical fiber coupler, an optical fiber environment, a magnetic field generating unit and a photoelectric detector, wherein the optical fiber environment comprises a left arm optical fiber, a right arm optical fiber and a PCFG (Photonic Crystal Fiber Grating). The magnetic control tunable optical fiber comb filter is characterized in that the PCFG cladding is provided with five large shaddock-form air holes of single-layer structures, and magnetofluid is filled into the large air holes through a capillary phenomenon and changes in the refraction index under the action of a variable magnetic field to change the effective refraction index of a PCFG cladding and cause the wavelength movement of a harmonic peak coupled between a PCFG base mode and a cladding mode so as to realize the tunability as the output characteristics of the filter. Because of different lengths of the left arm optical fiber and the right arm optical fiber in the optical fiber environment, two paths of light signals reflected by the PCFG have a light path difference and are subjected to interferences when returning to the optical fiber coupler so that a comb filter effect is generated in an output spectrum of the filter.

A non-integer decimation filter for decimating an input value includes a first integrator for integrating the input value in an input sample domain at an input sample rate and for generating a first integral of the input value at its output and a second integrator for integrating the first integral of the input value in the input sample domain at the input sample rate and for generating a second integral at its output. A calculation network is coupled to the outputs of the first and second integrators for combining the outputs of the first and second integrators with corresponding coefficients to generate intermediate output values in an output sample domain. A differentiator is configured to receive the intermediate output values from the calculation network and to generate a decimated output value at an output sample rate in which the output sample rate has a non-integer factor with respect to the input sample rate.

System and method for analyzing an input signal acquired from a physical system with a rotating element. A tachometer signal is received comprising rotation speed information for the rotating element. A time sequence is determined using the tachometer signal, comprising time values for the rotating element at substantially equal angle increments, e.g., by edge detection software or timer / counter. A software-based first digital interpolation filter, e.g., a Cascade-Integrator-Comb filter, is applied to the time sequence, generating a modified time sequence. A digitized data signal is received comprising data for the rotating element at substantially equal time increments. A second software-based digital interpolation filter is applied to the data signal, generating a modified data signal which is re-sampled using the modified time sequence to generate an angle domain data signal, comprising data signal values at substantially equal angle increments, where the angle domain data signal is usable to analyze the physical system.

The invention discloses an elimination method of slurry pulse signal pump stroke noise. The order formula (N=Fs / Fo) of a comb filter is utilized, wherein Fs is the sampling frequency of a slurry signal, and Fo is a product of the movement rate of a single slurry pump piston and the number of slurry pumps, and the order of the comb filter is determined; when the pump stroke noise is eliminated, a filtering process of a slurry pulse signal is realized by utilizing MATLAB software, and comprises the following steps: 1) collecting the slurry pulse signal on site; 2) according to the signal to noise ratio of the signal, determining the bandwidth (BW) of the comb filter, designing the required comb filter according to the BW and the determined order; 3) converting the slurry pulse signal to enable a signal value to be within an interval (-1,1), and obtaining a signal X(n); 4) loading the signal X(n) into the comb filter to carry out convolution filtering to obtain a filtered signal Y(n); and 5) plotting, and observing a signal filtering situation. The invention breaks through the restriction of a hardware circuit, the MATLAB software is utilized to effectively realize the filtering process of the slurry pulse signal, and meanwhile, the comb filter is applied to the slurry pulse signal so as to further enhance a filtering effect.

The invention relates to a post-processing method for removing ring artifacts in a CT (computed tomography) image, and the post-processing method comprises the following steps: converting the CT image with ring artifacts from a rectangular coordinate image to a polar coordinate image; extracting the ring image in polar coordinates with a comb filter in a polar coordinate image domain; converting the ring image extracted out of the polar coordinates to a ring image in rectangular coordinates; and subtracting the ring image in the rectangular coordinates from the original CT image with the ringartifacts to obtain a ring-free image. Through frequency domain comb filtering technology, the post-processing method provided by the invention subtracts the corresponding ring artifact image from the original image, without reduction of image resolution and change of quality of the original image. The post-processing method achieves the processing effect, and meanwhile the speed meets product requirements and has space for further optimization, so that the post-processing method is fully suitable for a CT machine with higher requirements for the reconstruction speed.

The invention discloses a method and a device for demodulating a fiber bragg grating (FBG) sensor. The method comprises the following steps of: controlling a wavelength scanning laser device to generate narrow-band scanning laser rays with continuously changed wavelengths by using a computer; splitting beams of the narrow-band scanning laser rays generated by the wavelength scanning laser device; enabling a generated reflection spectrum to enter a photoelectric detector again via an optical fiber coupler to be converted into electric signals after the beam-split narrow-band scanning laser rays respectively enter the FBG sensor to be measured and a reflecting FBG comb filter with a temperature compensation package function via the optical fiber coupler, and acquiring the electric signals by the computer after the electric signals are amplified; obtaining wavelengths of peaks of the reflecting FBG comb filter with the temperature compensation package function by the computer through a peak-detection algorithm; calibrating the reflection spectrum of the FBG sensor by the wavelengths; and calculating an absolute wavelength value of the FBG sensor.

The invention provides an all-optical-fiber current transformer system with a temperature measurement function. The all-optical-fiber current transformer system comprises a current sensing optical path and a temperature sensing optical path, the current sensing optical path comprises a laser device, an optical fiber coupler, an optical fiber circulator, an optical fiber polarizer, a phase modulator, an optical fiber delay ring, a current transformer sensing ring and a first photoelectric detector in sequence connection, and the first photoelectric detector is connected with an end D3 of the optical fiber circulator. The temperature sensing optical path comprises a laser device, an optical fiber coupler, an optical fiber temperature sensor and an optical comb shaped filter in sequence connection, and the optical comb shaped filter is connected with an end C of the optical fiber coupler. The all-optical-fiber current transformer system has the advantages that the temperature sensing optical path is added, current and temperature measurement functions are integrated, temperature compensation can be performed for the current transformer sensing ring, a corrected current value serves as a judgment basis of relay protection, the optical fiber temperature sensor and the current transformer sensing ring can jointly participate in relay protection, and accordingly accuracy of relay protection judgment is improved.

A novel sigma delta amplitude modulator having a noise transfer function adapted to shift quantization noise outside at least one frequency band of interest. In one embodiment, the sigma delta amplitude modulator includes a programmable order low pass stage. In a second embodiment, the sigma delta amplitude modulator incorporates comb filtering wherein each comb filter comprises a plurality of fingers to permit greater programmability in the frequency location of notches. A polar transmitter incorporating the sigma delta amplitude modulator is presented that shapes the spectral emissions of the digitally-controlled power amplifier such that they are significantly and sufficiently attenuated in one or more desired frequency bands.

Apparatuses and methods for using proximal probes. A method includes measuring motion of an oscillating probe, producing a signal indicative of motion of the oscillating probe, and filtering the signal indicative of motion of the oscillating probe. In one embodiment, filtering includes performing signal decomposition to produce a filtered signal. In another form, filtering includes performing a Fourier transform, comb filtering in the frequency domain, and performing an inverse Fourier transform to produce a filtered signal. In another embodiment, filtering includes amplifying specific frequencies of the signal indicative of motion of the oscillating probe. Apparatuses according to the present invention are also provided.

Systems and methods are provided for converting a digital signal into an analog signal. A digital-to-analog converter assembly comprises a delta-sigma modulator, a digital-to-analog converter, an analog filter, and a comb filter. The delta-sigma modulator processes a digital input signal to produce a digital output signal having at least one associated high dynamic range frequency band. The digital-to-analog converter converts the digital output signal into an analog output signal having at least one associated high dynamic range frequency band. The associated high dynamic range bands have respective frequency characteristics. An analog filter assembly filters the analog signal. The analog filter has at least one passband. A comb filter assembly attenuates the analog signal output of the filter assembly to improve signal to noise ratio.

A configurable hybrid superheterodyne spectrum analyzer for deriving process state parameters from detected modulated light emitted by a plasma receives and conditions the electric signals converted from the modulated light for subsequent superheterodyne mixing at a specific intermediate frequency (IF) that is lower than the frequency of the modulated light. Signal conditioning includes filtering noise, aliasing and DC and / or amplifying or de-amplifying the signal. Once mixed, the superheterodyne signal is further filtered by an IF filter to define the signal bandwidth characteristics relevant to the process state parameters. The IF filter may configurably employ multiple filter functions such as Gaussian filtering of increasing widths and / or comb filtering for multiple passbands in the frequency spectrum. Finally, the IF mixed and filtered signal is digitized with respect to the specific intermediate frequency using an IF digitizer. The processed signal is then passed to a signal analyzer for derivation of process state parameters. The system may further include a controller for receiving information from the signal analyzer regarding signal processing requirements and then actively configuring one or all of the signal conditioner filter, signal conditioner amplifier, IF filter and IF digitizer to meet those requirements.

An embodiment of the present invention provides an apparatus, comprising a multilayer filter including a first resonator on a first layer of dielectric material or low-temperature-co fired-ceramic, a second resonator coupled to the first resonator on a second layer of dielectric material or low-temperature-co fired-ceramic, a third resonator coupled to the second resonator and cross coupled to the first resonator, and wherein a voltage tunable dielectric capacitor is connected to at least one of the resonators to electrically tune the multilayer filter.

The invention discloses a stepped impedance resonator (SIR) coaxial-cavity band-pass filter, which is of a comb-shaped filter structure formed by coupling an SIR fundamental resonator unit. The SIR fundamental resonator is composed of three parts of a bar-shaped inner layer metal transmission line, an outer layer cylinder metal wall in coaxial with the inner layer metal transmission line and a middle medium layer. The inner layer metal transmission line is an SIR resonance rod formed by combining two sections of coaxial transmission lines with different diameters. An open circuit coaxial bored hole and a tuning screw are arranged at the top end of the open circuit end of the metal transmission line, and the top end of the open circuit end of the metal transmission line is provided with a windowing coupling screw coupling structure and an input output direct coupling structure. The filter has good spurious frequency rejection characteristics, is small in size compared with a traditional base station, meets requirements of modern communication systems for miniaturization, low insertion loss, high selectivity and wide attenuation band on filters, and can be widely applied to modern mobile communication systems.

An OFDM receiver receives OFDM symbols in the frequency domain and comb filters and then punctures the OFDM symbols to leave symbols with actual pilot information and with null values at the data symbols. The receiver provides the punctured OFDM symbols to an OFDM symbol queue. A virtual pilot interpolator is coupled to the punctured OFDM symbol storage to generate virtual pilot information introduced to OFDM symbols. The interpolator may be a two dimensional Wiener filter. The receiver also includes a time domain channel estimator that processes a first OFDM symbol including virtual pilot information to generate a channel impulse response for the first OFDM symbol. A frequency equalizer equalizes the OFDM symbol in response to the channel impulse response for the first OFDM symbol.

The embodiment of the invention provides a method for modifying a sound channel delay parameter of a multi-channel signal. The method mainly comprises the following steps of: carrying out down mixed processing on the multi-channel signal to obtain a processed signal; calculating energy distribution of the processed signal; and judging whether the processed signal generates a comb filtering effect according to the energy distribution of the processed signal, if so, modifying the sound channel delay parameter of the multi-channel signal. According to the method disclosed by the invention, whether the comb filtering effect is generated is judged according to the energy distribution of the processed signal obtained by carrying out down mixed processing on the multi-channel signal, thereby whether the sound channel delay parameter is required to be modified is judged to eliminate the comb filtering effect and further provide better reconstruct stereophonic sound and a sound image and the definition of the multi-channel signal.

I describe and claim a temporal comb filtering system and method. The temporal comb filter system includes a comb filter to temporally process separated luminance and chrominance components from an image field responsive to image data from at least one other image field and a panel to display the processed components. The comb filter includes a cross-chroma detector to detect luminance information within chrominance data from a first image field responsive to chrominance data from at least one other image field and a cross-luma detector to detect chrominance information within the luminance data from the first image field responsive to the luminance data from at least one other image field.