140 results about "Half-band filter" patented technology

A filter system comprising three or more filters, each having different passbands, and an impedance adjusting network coupled between a filter system ports and each of the ports of at least two of the filters to adjust the port impedances of the filters coupled to the network. The adjusted port impedance of each filter at a frequency representative of at least one of the other filters coupled to the network is at a non-loading level. In one embodiment, the filter system is configured for use in a wireless communication receiver and / or handset.

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 tunable narrow-band filter that includes a sigma-delta modulator. In one embodiment, a conventional DC canceler is modified to include a re-quantizer in the feedback loop in the form of a ΣΔ modulator. In another embodiment, a digital receiver employs a processing chip, such as an FPGA, that includes a ΣΔ modulator to requantize oversampled control signals in the digital receiver. In still another embodiment, a wide-bandwidth sigma-delta loop has a tunable center frequency.

An adaptive echo cancellation system and method employing an algorithm suitable for a digital repeater with sub-band filtering is disclosed. Cross- and auto-correlation measurements used to estimate the residual coupling are computed from normalized cross and power spectrums which avoid the problems associated with narrow bandwidth signal components. The normalized cross- and power spectra are additionally masked in frequency to reduce the influence of interfering spectral components outside of the passband of the sub-band filter. Regularization of the iterative estimation process is applied to maintain stability and compensate for the bandwidth reduction associated with the sub-band filter and the spectral mask.

The invention discloses a sampling rate conversion device and a sampling rate conversion method with the bandwidth being continuously variable. The sampling rate conversion device comprises an upper sampling rate conversion unit and a lower sampling rate conversion unit, wherein the upper sampling rate conversion unit comprises a shaping filter, an integral multiple interpolation module A, a fractional multiple interpolation module A, a DAC (digital-to-analog converter) and a control module A, the shaping filter receives a sequence to be sent, and the sequence to be sent is sequentially processed by the integral multiple interpolation module A, the fractional multiple interpolation module A and the DAC and then outputted, the lower sampling rate conversion unit comprises an ADC (analog-to-digital converter), a fractional multiple interpolation module B, an integral multiple extraction module B, a matched filter and a control module B, signals of a receiving end are inputted into the ADC, the signals are sequentially processed by the fractional multiple interpolation module B, the integral multiple extraction module B and the matched filter and then outputted, and the control module controls the integral multiple interpolation times, the integral multiple extraction times and the fractional multiple interpolation times. According to the invention, the hardware resource occupation rate is low, the number of half-band filters can be increased or decreased according to a relation between a target sampling rate and an input signal symbol rate, thereby adapting to sampling rate conversion processing of any signals with the bandwidth being variable.

A flexible multi-path RF adaptive tuning network switch architecture that counteracts impedance mismatch conditions arising from various combinations of coupled RF band filters, particularly in a Carrier Aggregation-based radio system. In one version, a digitally-controlled tunable matching network is coupled to a multi-path RF switch in order to provide adaptive impedance matching for various combinations of RF band filters. Optionally, some or all RF band filters also include an associated digitally-controlled filter pre-match network to further improve impedance matching. In a second version, some or all RF band filters coupled to a multi-path RF switch include a digitally-controlled phase matching network to provide necessary per-band impedance matching. Optionally, a digitally-controlled tunable matching network may also be included on the common port of the multi-path RF switch to provide additional impedance matching capability.

The invention discloses a method for reducing the signal peak-to-average ratio, which comprises the following steps: calculating synthesis peak clipping pulse shaping filter coefficients according to intermediate frequency digital signals; acquiring cancellation pulses; and after delaying the intermediate frequency digital signals, performing operation with the cancellation pulses and outputting signals with low peak-to-average ratio. The invention also discloses a device for reducing the signal peak-to-average ratio, which comprises a synthesis peaking pulse shaping filter, a tapping value calculating element, a first frequency spectrum moving unit, a digital filtering unit, a second frequency spectrum moving unit, a half-band filter, a delay unit and a cancellation unit. The method and the device can be adaptable to multi-carrier signals of each carrier frequency point flexibly configured in the available frequency band range, optimize the peak clipping effect, avoid signal distortion and save expenses.

A zeroth-order resonator is characterized in that a complementary split ring resonator is etched on a grounding layer; and a slit capacitor is etched on a microstrip signal line and is located above the complementary split ring resonator. The method comprises the following steps: setting an initial value for each parameter of the zeroth-order resonator; subjecting the zeroth-order resonator to Bloch analysis according to the initial values to obtain a resonant frequency f1; adjusting the parameter until f1 is equal to f0; and calculating input admittance near the resonant frequency f0 to obtain admittance slope parameter of the zeroth-order resonator. A narrow-band filter has a complementary split ring resonator and includes a plurality of zeroth-order resonators and a plurality of J-converters in alternated arrangement. By adopting the complementary split ring resonator, the zeroth-order resonator has large susceptance slope parameter, and the filter using the zeroth-order resonator has narrower bandwidth. The narrow-band filter can be used for separating signals among different channels in a communication system, and a medium-frequency narrow-band filter used for RF / microwave measurement instruments can acquire high frequency resolution.

The invention discloses an ultra wide-band filter based on double minor matters loading harmonic oscillator. The ultra wide-band filter based on double minor matters loading harmonic oscillator comprises a micro-strip substrate, a front part, a reverse part and an input\output port. The front part and reverse part are respectively located on the two sides of the micro-strip substrate. The reverse part is regarded as a metal earth plate of the filter. The input\output port has two ports which are respectively a first input\output port and a second input\output port. The front part comprises a first uniform transmission line unit, a second uniform transmission line unit, a first paralleled coupler feeder, a second coupler feeder, and a double minor matters loading harmonic oscillator. The ultra wide-band filter is compact in structure, small in size, low in cost, and good in speciality.

The invention provides an ultra-wide-band filter with high selectivity and an ultrahigh attenuation band restrain effect, which is composed of a first input / output port, a second input / output port, an interlayer medium substrate, an upper layer micro-strip structure arranged on the interlayer medium substrate and an underlying metal floor board. The upper layer micro-strip structure comprises a first feed network, a multi branch knot loading multimode resonator and a second feed network. The multi branch knot loading multimode resonator of the upper layer micro-strip structure has five resonance modes in an ultra-wide-band frequency band scope, a transmission zero is generated above and below a passband respectively, and passband selectivity is greatly improved. In addition, generated zero and frequency doubling zero of the zero restrains high sequence resonance modes of the multimode resonator, and restraining effects of an upper attenuation band of the passband are greatly broadened. The ultra-wide-band filter has good passband character, high passband selectivity and ultra-high attenuation band restraining effect, and is applicable to ultra-wide-band wireless communication systems with high standard communication.

The invention provides an oversampling 64-time sigma-delta modulation circuit with an effective bit being 18. The circuit comprises an interpolation filter and a sigma-delta modulator. The interpolation filter is used for conducting oversampling interpolation and filtering on digital input signals. The input end of the sigma-delta modulator is connected with the output end of the interpolation filter, the sigma-delta modulator is used for modulating oversampled digital signals, shaping quantized noise introduced by a quantizer, moving noise in the signal bandwidth out of the bandwidth, and meanwhile guaranteeing that transmission of the signals is not affected, and output 1-bit 0 / 1 code streams need to be restored through a backward-stage analog reconstruction filter so as to acquire analog signals. An improved structure is adopted in a half-band filter in the interpolation filter so that the area of the half-band filter can be greatly reduced; for the sigma-delta modulator, a monocycle high-order structure easier to achieve is adopted, the stability problem is analyzed, the high signal to noise ratio is achieved, and meanwhile stability of the modulator is guaranteed.

The present invention discloses an adaptive sub-band audio feedback suppression method. The method comprises the steps of segmenting an input signal according to a sampling sequence to obtain data blocks; allowing the data blocks to pass a sub-band filter to obtain sub-band signals of a power amplification signal and an input signal; allowing the sub-band signals to pass an adaptive sub-band feedback filter to deduce a microphone feedback sub-band signal generated by a speaker signal, performing weighing energy analysis and statistics on the sub-band signal, and correcting the adaptive sub-band feedback filter; synthesizing input sub-band signals expect the feedback sub-band signal and recovering to obtain a time domain signal; and sending the recovered time domain signal to the speaker for sound amplification. The method has the advantages that the signal filter is segmented into sub-bands, so that the correlation between the sub-band signals is lowered, a convergence problem of the adaptive filter is solved, data processing amount of the system is reduced, the feedback suppression processing efficiency is improved, the sound gain of the sound amplification system is improved, the sound amplification quality is improved, and the sound gain can be increased by over 6 decibel stably, at most 15 decibel.

The invention discloses a coaxial cavity dual-band filter based on a stepped impedance structure. The filter provided by the invention is formed by coupling of several stepped impedance coaxial cavity resonator units. Each stepped impedance coaxial cavity resonator unit is composed of three parts, namely two rod-shaped solid metallic conductors, a tubular metallic wall and a filler. The filler is air and is positioned in a resonant cavity between the tubular metallic wall and the rod-shaped solid metallic conductors. The upper and lower ends of the tubular metallic wall are provided with outer cover plates for sealing the resonant cavity. The several stepped impedance coaxial cavity resonator units are arranged in a linear parallel structure. The two rod-shaped solid metallic conductors are two coaxial cylinders with different diameters and are divided into a lower conductor cylinder and an upper conductor cylinder. The two conductor cylinders are connected in series up and down. The lower conductor cylinder is electrically connected with a feeder line of an input or output port. According to the invention, two passbands are realized by the stepped impedance coaxial cavity resonator units; passband frequency ratio adjustable range is large; the size of the filter is small; and the structure of the filter is simple and reasonable.

The invention discloses a multimode wide-band filter based on a multi-branch loaded square resonance ring, which mainly solves the problem that the circuit size of a conventional multimode wide-band filter is limited by the area of the resonance ring. The filter comprises a micro-band dielectric substrate (1), a metal grounding plate (2), a square resonance ring (3) and a pair of input and output feed lines (8). The square resonance ring (3) comprises a square metal ring (4), a pair of equilong perturbation branches (5), a pair of impedance matching metal pieces (6), and a pair of transmission zero point branches (7). The two equilong perturbation branches (5) are located at a pair of external opposite angles of the square metal ring (4). The two same impedance matching metal pieces (6) are located at the other pair of opposite angles of the metal ring (4). The transmission zero branches (7) and the equilong perturbation branches (5) are connected in parallel or located in the metal ring (4) and are connected with the inner edge of the metal ring (4). The pair of input and output feed lines (8) is symmetrically arranged above the micro-band dielectric substrate (1) horizontally, and is parallel to the tail ends of the perturbation branches. According to the multimode wide-band filter, the circuit size of the filter is reduced, and the circuit is miniature, and the filter can be applied to wireless communication systems.

The invention discloses a double-frequency combiner with high relative bandwidth, which comprises a band rejection filter arranged on a chamber and used for enabling ultra wide band signals to pass and a band filter used for enabling relative narrow band signals to pass. The band rejection filter comprises a conduction band. The band filter comprises a plurality of harmonic oscillation columns. After the band rejection filter is combined with the band filter, the signals are output through a common port. A combination part is arranged on the harmonic oscillation column of the band filter close to the common port. The combination part is coupled with the conduction band by means of slot coupling to couple signals between the two filters. The double-frequency combiner with high relative bandwidth widens the range of use of the combiner, and overcomes the limitation that the conventional combined can only be used in the mobile communication system; in addition, as sufficient gaps are reserved between the internal parts, the power capability is improved. Furthermore, the invention has the advantages of high electric indices, low cost, simple process and the like.

A flexible multi-path RF adaptive tuning network switch architecture that counteracts impedance mismatch conditions arising from various combinations of coupled RF band filters, particularly in a Carrier Aggregation-based (CA) radio system. In one version, a digitally-controlled tunable matching network is coupled to a multi-path RF switch in order to provide adaptive impedance matching for various combinations of RF band filters. Optionally, some or all RF band filters include an associated digitally-controlled filter pre-match network to further improve impedance matching. In a second version, some or all RF band filters coupled to a multi-path RF switch include a digitally-controlled phase matching network to provide necessary per-band impedance matching. Optionally, a digitally-controlled tunable matching network may be included on the common port of the multi-path RF switch to provide additional impedance matching capability. In a third version, CA direct mapped adaptive tuning networks include filter tuning blocks for selected lower frequency bands.

A multi-band RF circuit has receive paths for two or more bands, and transmit paths, a bidirectional one-in multiple-out transmission line junction (100) for combining the paths for coupling to an antenna. A switch combines transmit and receive paths, and a receive path circuit (110, 150, 160, 230, 240) is arranged to pass signals of its band, and appear open circuit to signals of the other bands. This means the combiner no longer needs to cut off the receive paths when they are not used. This can reduce components and thus reduce losses in the transmit paths for longer battery life or greater transmit range. A band filter (SAW) and a complementary circuit can achieve the open circuit. The bands can include GSM and GPS bands, the circuits can be used in tri band mobile handsets and handsets for future 3G bands, or base stations.

The invention discloses a subsynchronous oscillation inter-harmonic wave extracting method of online adaptive frequency change. The method comprises steps of firstly, acquiring original sampling data of phase current and phase voltage of a circuit in real time in an online manner, or through the original sampling data of the phase current and the phase voltage, calculating instantaneous power of the circuit so as to obtain input data to be calculated and extracted; carrying out filtering on the input data through a narrow-band comb-shaped filter group; acquiring real-time output data of each narrow-band filter; comparing output real-time waveform peak values of the narrow-band filters so as to obtain an extreme point of a broadband amplitude value, wherein the central frequency of the filter corresponding to the extreme point is the main oscillation frequency of the oscillation; and carrying out data fitting on the output data of the filters through zero passage comparison, and determining the precise main oscillation frequency. According to the invention, the algorithm can be applied to an online monitoring device of the subsynchronous oscillation monitoring; and online rapid recognition of oscillation signals is achieved.

The invention discloses a low-power-consumption multi-order interpolation half-band filter with a two-phase structure. The filter comprises m delay functional modules, a multi-input adder and a sampling functional module, wherein m is a natural number which is more than or equal to 1; and n is an order number and is equal to 4m+2. In the multi-order interpolation half-band filter with the two-phase structure, the circuit structure is optimized by fully utilizing the coefficient characteristic of the interpolation half-band filter, a multiplier is eliminated on the premise of keeping the performance invariant and an additional delay time register is not added, so that the total logic operation amount is reduced, the hardware overhead is reduced, the chip area is reduced, and the power consumption is further optimized. The multi-order interpolation half-band filter with the two-phase structure can be widely applied to the fields of communication systems, interface circuits, software radio and the like.

The invention discloses a narrow-band filter based on a phase modulation apodized grating. An input single-mode waveguide is connected to an asymmetric gradient directional coupler via an input tapered waveguide; the asymmetric gradient directional coupler is connected with a curved output waveguide to realize reflective signal output; an upper port at a right end of the asymmetric gradient directional coupler is connected to a left end of an antisymmetric multimode waveguide apodized grating, and a right end of the antisymmetric multimode waveguide apodized grating is connected to the outputsingle-mode waveguide through the output tapered waveguide in order to achieve straight-through end signal output. A grating reflective signal is extracted by the asymmetric gradient directional coupler, the tolerance is large, and the insertion loss is small; the narrow bandwidth is adjustable by adjusting the spacing between the grating teeth and the waveguides; the multimode waveguide only supports two modes, which can avoid crosstalk caused by the coupling of other modes; apodization is realized by adjusting the phase of the grating, and the grating filter with the high sideband suppression ratio is realized, which greatly improves the performance of the grating filter.

The invention relates to an electromagnetic wave multi-band filter with side micro-cavities and a metal-medium-metal waveguide coupled, and belongs to the technical field of filter design. According to the electromagnetic wave multi-band filter, the metal-medium-metal structure is used, the middle medium part is an insulating transparent layer and the waveguide is formed; multiple sets of side micro-cavities are manufactured in the metal parts and each set of side micro-cavities corresponds to a rectangular transmission stop band. Particularly, due to the fact that gold is very few in loss in the terahertz wave band, gold can be seen as an ideal electric conductor; the bandwidth of the filter can be adjusted by adjusting the width of the micro-cavities; multi-band filtering of the terahertz wave band can be realized. The electromagnetic wave multi-band filter has the advantages that the bandwidth and the number of the stop bands are adjustable; minimization and integration can be achieved conveniently; the electromagnetic wave multi-band filter can also be applied to other electromagnetic frequency bands such as the optical fiber communication frequency band and the microwave frequency band, and the requirements of different frequency bands can be met.

The invention discloses a dual-band bandpass filter based on a single rectangular SIW structure. The present invention is based on a rectangular SIW structure and controls the first four resonant modes of the filter, namely TE101, TE201, TE301 and TE401 modes, by using a method of metal via disturbance. TE101 and TE201 combine to form a first passband, TE301 and TE401 combine to form a second passband. In addition, the bandwidth and spacing of the two passbands can be tuned relatively independently by disturbing vias through movement. At the same time, the offset input and output feeders introduce four transmission zeros into the filter, which improves the stopband attenuation of the filter. By utilizing single SIW cavity mode reasonably, it meets the miniaturization requirement of modernmulti-standard RF system and solves the problems of large size and complex design of a traditional dual-band filter.

A decimation filtering apparatus using interpolated second order polynomials compensates for a droop caused by a CIC (Cascaded Integrator-Comb) filter (51). The decimation filter includes a CIC decimation filter (51) for decimation filtering the sampling signal to downconvert a sampling signal; an ISOP filter (53) for monotonically increasing an output of the CIC decimation filter (51) to compensate for a passband droop caused by the CIC decimation filter (51); a multistage halfband filter (55) including at least one modified halfband filter for 1 / 2 decimating a signal output from the ISOP filter (53), the multistage halfband filter (55) decimating the signal output from the ISOP filter (53) to downconvert the signal; and a programmable FIR (Finite Impulse Response) filter (57) for compensating for a passband droop of a signal output from the multistage halfband filter (55).

In accordance with some embodiments of the present disclosure, a method may include digitally pre-distorting a digital baseband signal with an opposite phase of a C-IM3 distortion term such that the pre-distortion and C-IM3 distortion cancel each other out in a transmitter. The method may also include digitally conditioning the pre-distorted digital signal in order to provide a flat amplitude response of a composite filter comprising a baseband filter and a digital half-band filter of the transmitter, and to provide a linear phase response for the composite filter.

The present invention discloses a method and system for processing multi-rate audio from multiple audio processing sources. Audio codecs in wireless devices can be used to upsample two or more audio signals to the same data sampling rate. Each audio signal, such as digital audio, speech and multi-tone ringtones, may be received at at least one of a plurality of data sampling rates. Before upsampling, the audio signal can be equalized and / or compensated using FIR filters or using IIR filters to reduce overall processing response time. Multiple half-band interpolation operations may accomplish the upsampling. The first half-band filter can be replaced by an IIR filter to reduce the overall processing response time. The gain of the upsampled data can be adjusted to reduce noise effects. The channels of the upsampled audio signal are mixed and then further upsampled for delivery to an output device. The up-sampled mixed audio signal may be down-sampled for transmission to a Bluetooth radio.

The invention discloses a dual-mode three-way wide-band filter based on a multi-branch loaded square resonance ring, which mainly solves the problem that the frequency selectivity of a conventional dual-mode three-way wide-band filter is difficult to control. The filter comprises a micro-band dielectric substrate (1), a metal grounding plate (2), two symmetrical multi-branch loaded square resonance rings (3 and 4) and input and output feed lines (11). Each multi-branch loaded square resonance ring comprises a square metal ring (5), a lower perturbation branch (6), an upper perturbation branch (7), a transmission zero point branch (8), and a pair of perturbation metal sheets (9 and 10). The two perturbation branches (6 and 7) are located at a pair of external opposite angles of the square metal ring (5). Each perturbation branch is parallel to both sides of the metal ring (5). The pair of perturbation metal sheets (9 and 10) is located inside the other pair of opposite angles of the metal ring (5). The transmission zero point branch (8) is connected with the lower perturbation branch (6) in parallel and the input and output feed lines (11) are symmetrically placed above the micro-band dielectric substrate (1) and extend into one side of the metal ring (5) and the middle of the upper perturbation branch (7) in parallel. According to the filter, the frequency selectivity is improved, and the filter has good out-of-band rejection and can be applied to a wireless communication system.

An adaptive echo cancellation system and method employing an algorithm suitable for a digital repeater with sub-band filtering is disclosed. Cross- and auto-correlation measurements used to estimate the residual coupling are computed from normalized cross and power spectrums which avoid the problems associated with narrow bandwidth signal components. The normalized cross- and power spectra are additionally masked in frequency to reduce the influence of interfering spectral components outside of the passband of the sub-band filter. Regularization of the iterative estimation process is applied to maintain stability and compensate for the bandwidth reduction associated with the sub-band filter and the spectral mask.

The invention discloses a low-consumption digital decimation filter bank with variable decimation multiples and a digital decimation and filtering method. The low-consumption digital decimation filter bank and the digital decimation and filtering method are used for the filtering and the decimation of data. The filter bank comprises a first stage, a second stage and a third stage, wherein the first stage is a cascading comb-shaped integrating filter which is used for achieving the decimation movement with large multiples, the second stage is a half-band filter of at least one stage which is used for achieving the decimation movement of the second stage, the third stage is a compensating filter which is used for compensating pass band damping and carrying out filtering decimation movement, and the first stage is the cascading comb-shaped integrating filter with variable decimation multiples in a non-recursion mode. The method comprises the steps of determining decimation ratios and the system structure of the decimation filter bank, decomposing the transfer function of the cascading comb-shaped integrating filter, selecting the decimation ratios meeting requirements to for combination and carrying out multi-phase decomposition on the cascading comb-shaped integrating filter, the half-band filter and the compensating filter. The low-consumption digital decimation filter bank with the variable decimation multiples and the digital decimation and filtering method have the advantages that the number of registers working close to high frequency can be reduced, resource consumption is reduced, and power dissipation is reduced.

A weighted broadband time reversal operator resolution acoustic imaging method includes the steps of conducting fast Fourier transform on a signal received through a receiving and transmitting combined array, dividing the signal into multiple sub-bands through a narrow-band filter, resolving the time reversal operator singular value corresponding to each sub-band, relating the feature vector corresponding to the maximum feature value to the transmitting vector based on an acoustic propagation model so as to obtain an ambiguity function, extracting the maximum value of the ambiguity function of each sub-band and the two-dimensional sound field space corresponding to the sub-hand, designing a weighting coefficient according to the maximum feature value, weighting the ambiguity functions, and representing a three-dimensional image after accumulating the results of all the sub-bands in a coherent mode. The method has the advantages that the scattering properties of targets are applied to the broadband time reversal operator resolution imaging method in a weighted mode, broadband information is fully used, the spatial features of expansibility targets are truly displayed, and the effectiveness and the reliability of the scheme are verified through experiments.