118 results about "Tuned filter" patented technology

The invention discloses a radio frequency signal interference intelligent suppression management system and method based on image recognition. The system comprises a multi-source sensing module, a fusion analysis module, a dynamic suppression module and an execution feedback module. The multi-source sensing module forms a radio frequency original signal set containing frequency spectrum features and time domain waveforms; the fusion analysis module receives the radio frequency original signal set and extracts an interference source feature vector in the radio frequency original signal set through a pre-trained convolutional neural network to generate a fusion decision signal; the dynamic suppression module receives the fusion decision signal and activates a corresponding algorithm in a preset suppression strategy library according to the interference type identifier; and the execution feedback module receives the real-time control signal and drives the tunable filter, the phased-array antenna and the power amplifier to execute interference suppression operation. According to the intelligent suppression management system and method for the radio-frequency signal interference based on image recognition, the problems of fuzzy positioning of the radio-frequency interference source, single suppression strategy and lack of environmental perception capability can be solved.

The invention discloses a reconfigurable filter and a design method, relates to the technical field of radio frequency filter chips, and solves the problems that a tuned filter in the prior art cannot realize continuous adjustability, and is large in area and size and high in design complexity. The method comprises the following steps: determining an initial circuit of a quasi-elliptical filter network comprising a first LC structure and a second LC structure which are connected in series; calculating a first capacitance range of a variable capacitor in the first variable capacitor module according to a low-pass filtering network in the initial circuit; calculating parameters of each component in the low-pass filter network equivalent to the high-pass filter network through a frequency conversion method; calculating a second capacitance range of a variable capacitor in a second variable capacitor module according to the high-pass filtering network; optimizing the initial circuit of the reconfigurable filter according to the first capacitance range and the second capacitance range to obtain a reconfigurable filter circuit; the effect of adjusting the upper limit and the lower limit of the frequency by adjusting the voltage is achieved, and the circuit complexity is low.

A front-end module comprising a signal input configured to receive a radio-frequency (RF) signal, an antenna switch module (ASM), a power amplifier adapted to amplify the received RF signal to provide an amplified RF signal supplied to the ASM by way of one or more RF signal paths, and a tunable filter with selective coupled resonances. The selective coupled resonances are adapted to filter the RF signal output by the ASM to provide a filtered RF signal at an antenna node forming a signal output of the front-end module and configured to be coupled to an antenna.

The present invention relates to a compound of formula (A) in which the occurring groups and parameters have the meanings defined in claim 1, to a liquid crystal medium comprising a compound of formula (A) and to high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas, e.g. phased array antennas.

Aspects of this disclosure relate to a tunable filter with tunable rejection. The tunable filter includes mutually coupled inductors and a tunable impedance circuit electrically connected to at least one of the mutually coupled inductors. The tunable impedance circuit is configured to adjust at least two notches in a frequency response of the tunable filter by changing a state of a switch. The tunable filter can filter a radio frequency signal. Related methods, radio frequency systems, radio frequency modules, and wireless communication devices are also disclosed.

The invention provides a dual-carrier interphone. The dual-carrier interphone comprises a receiver link and a transmitter link, the receiver link consists of an antenna matching network, a first electric tuning filter, a low noise amplifier, a second electric tuning filter, a frequency mixer, an intermediate frequency amplifier, an intermediate frequency demodulation chip and a baseband chip which are connected in sequence; a transmitter link adopts single-carrier transmission or dual-carrier transmission, and the single-carrier transmission is realized through a baseband chip, a TCVCXO crystal oscillator, a phase-locked loop chip, a transmission VCO, a pre-amplifier, an attenuator, a pre-amplifier, a driving-stage amplifier, an excitation-stage amplifier and an antenna matching network which are connected in sequence; on the basis, the dual-carrier transmission switches the output of the receiving VCO to a channel of the pre-amplifier, and controls the transmitting VCO and the receiving VCO to transmit simultaneously. According to the invention, one-channel transmission or two-channel transmission is realized by adopting one transmission link, simultaneous two-channel simultaneous talkback can be realized, and the call efficiency is improved.

The invention provides a same and different frequency digital transfer station, which comprises a receiving link and a transmitting link, the receiving link comprises an antenna matching network, a first electric tuning filter, a low noise amplifier, a second electric tuning filter, a frequency mixer, an intermediate frequency amplifier, an intermediate frequency demodulation chip and a baseband chip which are connected in sequence; the transmitting link comprises a baseband chip, a control chip, a crystal oscillator, a phase-locked loop for transmitting, a transmitting VCO, a pre-amplifier, an attenuator, a pre-stage amplifier, a driving-stage amplifier, an exciting-stage amplifier and an antenna matching network which are connected in sequence; the crystal oscillator is further connected with the receiving phase-locked loop, the receiving phase-locked loop is connected with the receiving VCO, and the receiving VCO is connected with the frequency mixer. According to the invention, independent oscillation and phase-locked loops are adopted for receiving and transmitting, and the receiving VCO and the transmitting VCO lock corresponding working frequencies all the time when being started, so that the technical requirements of same-frequency transfer and different-frequency transfer are met.

The invention relates to a radio frequency front-end transmitting link and a state detection method thereof, the transmitting link adopts four-stage series power amplification circuits, and the four-stage series power amplification circuits comprise a first-stage power amplification circuit, a second-stage power amplification circuit, a third-stage power amplification circuit and a fourth-stage power amplification circuit; the first-stage power amplification circuit is composed of a first pi attenuator and a low-noise amplification chip and used for radio frequency small signal gain amplification. The second-stage power amplification circuit is formed by cascading a temperature compensation attenuator, a filter and a gallium arsenide power amplifier tube, and the filter is a broadband filter, a tuned filter or a frequency hopping filter; the third-stage power amplification circuit is formed by cascading a numerical control attenuator and a three-stage gallium nitride power amplifier tube; and the fourth-stage power amplification circuit is formed by cascading a second pi-type attenuator and a last-stage gallium nitride power amplifier tube. The method has the advantages of being high in dynamic range and good in adaptability in a software radio system.

The invention discloses a dual-optical-path gas detection alarm device based on an intermediate infrared SLD, and relates to the technical field of gas safety monitoring and alarm, in particular to the dual-optical-path gas detection alarm device based on the intermediate infrared SLD. In order to solve the problems that an existing gas alarm device is high in false alarm rate and delayed in response, and cannot realize multi-component gas concentration threshold value judgment and sound-light alarm linkage at the same time, the invention provides a dual-light-path gas detection alarm device based on an intermediate infrared SLD. Comprising an SLD light source module, an optical beam splitting and transmission module, a multi-reflection gas absorption cell, a main tunable filter array, a main photoelectric detector array, a reference tunable filter array, a reference photoelectric detector array, a differential amplifier array, a signal processing module, a display module and an alarm module. The method is suitable for the application fields of petroleum, natural gas, mining, underground space operation and the like.

The invention relates to a tunable filter bank for enhancing out-of-band rejection. The tunable filter bank comprises a first path switching module, a first filter bank, a second path switching module, a third path switching module, a second filter bank and a fourth path switching module, the first path switching module, the second path switching module, the third path switching module and the fourth path switching module are sequentially connected, and the first filter bank is connected between the first path switching module and the second path switching module. And the second filter bank is connected between the third path switching module and the fourth path switching module. The circuit can be equivalent to one or more of a high-pass filter, a low-pass filter, a transmission line and a band-pass filter, can process signal waveforms in different frequency band ranges, and has the characteristics of high control precision and high reliability.

The present invention provides a reverse-driven tunable F-P filter and a preparation method thereof, wherein the filter comprises a static mirror, a moving mirror, a supporting bridge pier, a microbridge, an electrode supporting structure and a top electrode; wherein the supporting bridge pier is prepared on the static mirror, and a cavity is formed between the supporting bridge pier and the static mirror; the moving mirror is located in the cavity, and an F-P resonant cavity is formed between the moving mirror and the static mirror, and a first stopper is prepared on the static mirror to prevent the moving mirror from contacting the static mirror; the microbridge comprises a central part and an edge part, wherein the central part is prepared on the side of the moving mirror facing away from the static mirror, and the central part acts as a bottom electrode for adsorption with the top electrode; the edge part is prepared on the top of the supporting bridge pier, and the electrode supporting structure is supported between the edge part and the top electrode. The present invention can determine the minimum cavity length by using a reverse driving method, and drives the moving mirror in the opposite direction of the static mirror, thereby overcoming the problem of adsorption instability in principle, thereby expanding the spectral detection range by increasing the cavity length tuning range.

The application discloses a kind of single crystal resonator ferromagnetic resonance line width fast screening device for magnetic tuning filter, belong to microwave component testing field, the testing device includes resonator (1), resonator (2), adjustable DC power supply (3) and vector network analyzer (4);Wherein, the resonator (2) after orientation is placed in resonator (1), the resonator (1) is connected with vector network analyzer (4) and adjustable DC power supply (3) respectively by data line, the application also discloses the method for using the above device to carry out single crystal resonator ferromagnetic resonance line width fast screening for magnetic tuning filter;The screening device of the application can realize the screening of one sample in 30 seconds, and the testing accuracy is good, can meet the demand of batch product screening test, is favorable for improving the tuning efficiency of magnetic tuning filter, reduces production cost, has very strong practical value.

The application relates to the technical field of tunable N-path filter, in particular to a tunable N-path reflection-free filter and a superheterodyne receiver. The tunable N-path reflection-free filter comprises a signal source, an N-path band-pass filter unit, an N-path band-stop filter unit, an output resistor and a phase-splitting clock generating circuit. The output end of the signal source is connected with one end of the N-path band-pass filter unit and the N-path band-stop filter unit respectively, the other end of the N-path band-stop filter unit is connected with the output resistor, the gate of a plurality of MOS switches in the N-path band-pass filter unit and the N-path band-stop filter unit is connected with the phase-splitting clock generating circuit, and the phase-splitting clock generating circuit outputs a control signal. The tunable N-path reflection-free filter provided by the application has excellent frequency selectivity, can effectively suppress high-order harmonics, and can adjust the passband and the stopband by changing the switching frequency. Meanwhile, the filter can eliminate the reflected signal, prevent the intermodulation interference and gain fluctuation of the mixer and the high-gain amplifier in the system.

A radio frequency (RF) monitoring apparatus (102), comprising: an RF forward input port (116) and corresponding reverse input port (118); a tunable filter (218); an RF detector (220); an electronic processor (202) comprising a tuning signal output (208), wherein the processor (202) is configured to selectively generate a tuning signal at the tuning signal output corresponding with one or more specified frequency sub-bands, to record RF power signals generated by the RF detector (220) corresponding with RF signals received at the forward and reverse input ports (116, 118) within the specified frequency sub-bands, and to provide monitoring signals determined from the recorded RF power signals.

The invention discloses a non-detachable direct identification method for characteristic parameters of a single-tuned filter, which comprises the following steps of: detecting the current of the single-tuned filter by using a current detection system, initializing the single-tuned filter to be detected to be in a zero state, applying a direct-current voltage source with constant amplitude to the single-tuned filter to be detected, sampling the current of the single-tuned filter, storing a sample, calculating a basic coefficient, a basic factor and an average basic factor, calculating an average estimation dynamic factor, calculating an estimation factor, and calculating a capacitance value, an inductance value and a resistance value of the single-tuned filter; according to the method, the single-tuned filter is used as a detection object, the characteristic parameters of the single-tuned filter are monitored in real time, a simulation model of the single-tuned filter is constructed, the identification method of the characteristic parameters in the filter is verified through experiments, and the identification method is confirmed to be accurate and reliable on the premise that the filter device is not disassembled and not damaged through analysis of experimental results. And the characteristic parameters of the single-tuned filter can be accurately estimated.

The invention discloses a dual-passband filter with all adjustable center frequency and bandwidth, and aims to provide a band-pass filter with low loss and wide tuning range. According to the technical scheme, each part comprises an input port, an output port, a coupled feeder line, a quarter-wavelength resonator with a variable capacitance diode loaded at the tail end, and a branch resonator with a variable capacitance diode loaded. According to the structure, a coupling line connected with a source and a load is adopted to feed a resonator in a slot coupling mode, the capacitance value of a variable capacitance diode is changed, and finally, the bandwidth and the center frequency are tunable. According to simulation verification, the center frequency of a high pass band of the all-tunable filter disclosed by the invention is continuously adjustable within 2.39-2.61 GHz, and at the moment, the center frequency of a low pass band is kept unchanged at 1.61 GHz and the bandwidth of 120 MHz; the center frequency of the low pass band is continuously adjustable within 1.45 GHz-1. 8GHz, and the center frequency of the high pass band is kept unchanged at 2.51 GHz and the bandwidth of 107MHz; the bandwidth of the high pass band is tunable in the range of 83-132MHz, the insertion loss fluctuates in the range of 1.16-1.45 dB, and at the moment, the center frequency of 1.6 GHz and the bandwidth of 122MHz of the low pass band are kept unchanged. The result shows that the microstrip filter with the tunable center frequency and bandwidth has the advantages of low loss, wide tuning range and wide application range.

An optimization design method of a double-tuned filter for a converter station comprises the following steps: calculating a total impedance function Z (omega) of the double-tuned filter; representing two tuning points of the filter through a full impedance function Z (omega) of the double-tuned filter, and defining an intermediate angular frequency of the double-tuned filter; the value of a high-voltage side capacitor C1 is determined according to the fundamental wave reactive compensation quantity QS1, and the values of L1, L2 and C2 are solved; and calculating the fundamental wave power loss of the medium resistor R of the double-tuned filter and the harmonic amplification coefficient H (omega) of the characteristic harmonic voltage of the AC filter of the converter station. And with the filtering performance, the resonance-free risk and the equipment investment cost as constraint conditions, the values of L1, L2 and C2 are optimized by adopting an optimization algorithm. According to the method, the optimal design process of an existing double-tuned filter topological structure for the converter station is analyzed in detail by considering the filtering effect and the harmonic amplification effect and combining the circuit principle, the filtering effect of the double-tuned filter for the converter station can be improved, and the harmonic resonance or harmonic amplification risk is avoided.

This invention relates to the fields of optical fiber communication and microwave photonics. Existing tunable dual-passband microwave photonic filters suffer from poor passband stability and cannot meet practical application requirements. This invention provides a narrow-band tunable dual-passband microwave photonic filter using a Brillouin fiber laser. It generates dual-tone pump light to excite the Brillouin using a tunable laser source and an intensity modulator. Combined with a Brillouin fiber oscillator and a cascaded Fabry-Perot cavity, the Brillouin gain spectrum is narrowed to the kHz level. Simultaneously, the different periodic resonant frequencies of the two ring cavities effectively suppress side modes, filtering out the desired frequency band signal. Furthermore, by synchronously tuning the center frequencies of the two passbands of the filter by changing the pump light wavelength, and simultaneously controlling the output frequency of the signal generator, the frequency interval between the two passbands is changed, ultimately realizing a narrow-linewidth tunable dual-passband microwave photonic filter.

The invention relates to a generation system and a generation method of a three-band coherent microwave signal. The system comprises a laser, an electro-optical modulator, an optical fiber ring, a photoelectric detector, a first bridge, a second bridge, a first broadband filter, a second broadband filter, a third broadband filter, a tunable filter, a first amplifier, a second amplifier, a third amplifier, a fourth amplifier, a coupler, an external signal source, a signal generator and the like. The generating system disclosed by the invention is a Fourier domain mode-locked photoelectric oscillator system for generating coherent microwave signals of three frequency bands based on difference frequency injection locking, and a Fourier domain mode-locked photoelectric oscillator autonomously-generated signal is combined with an external injection signal; therefore, multiple frequency band sweep frequency signals with good coherence and strong tunability can be output at the same time. The generated microwave signals of three frequency bands have good tunability and coherence, and the formed three-loop Fourier domain mode-locked optoelectronic oscillator system can be applied to multiple fields.

The invention relates to the technical field of tunable N-path filters, in particular to an adjustable N-path non-reflection filter and a superheterodyne receiver, the adjustable N-path non-reflection filter comprises a signal source, an N-path band-pass filtering unit, an N-path band-stop filtering unit, an output resistor and a split-phase clock generation circuit; wherein the output end of the signal source is connected with one end of the N-path band-pass filtering unit and one end of the N-path band-stop filtering unit, the other end of the N-path band-stop filtering unit is connected with the output resistor, and the split-phase clock generation circuit is connected with grid electrodes of a plurality of MOS switches in the N-path band-pass filtering unit and the N-path band-stop filtering unit and outputs control signals. The adjustable N-path non-reflection filter provided by the invention has excellent frequency selectivity, can effectively suppress higher harmonics, and can adjust a pass band and a stop band by changing the switching frequency. Meanwhile, the filter can eliminate reflected signals and prevent the reflected signals from inducing a mixer and a high-gain amplifier in a system to generate intermodulation interference and gain fluctuation.

The invention discloses a double-tuned filter, which comprises a filter module and a switch, and is characterized in that the filter module comprises a first series group which is formed by connecting a first inductor, a first resistor and a second capacitor in series; the second series group is formed by connecting a second inductor and a second resistor in series; the first series group and the second series group are connected in parallel and then are connected in series with the first end of the first capacitor; and the second end of the first capacitor is connected in series with the first end of the switch. By introducing the double-tuned filter, harmonic suppression of characteristic frequency generated by an elevator frequency conversion system during constant-speed operation of an elevator is realized, so that torque pulsation generated during constant-speed operation of an elevator permanent magnet motor is effectively suppressed, vibration and noise during operation of the elevator are reduced, and comfort of the elevator is improved. The invention further discloses an elevator permanent magnet synchronous traction control system.

The invention discloses a low-loss high-tunability BZT laminated dielectric film and a preparation method thereof, the laminated film comprises a substrate, a BZT film layer and a zinc niobate-based microwave dielectric ceramic film layer, and the chemical general formula of the zinc niobate film layer is Zn [(Ge0. 5Mo0. 5) xNb1-x] 2O6. A ceramic target material is synthesized by adopting a solid-phase reaction method, and thin film layers are sequentially deposited through a magnetron sputtering technology to construct a heterostructure. The high dielectric constant of BZT and the low loss characteristic of zinc niobate are combined, the frequency characteristic is remarkably improved, the dielectric loss is effectively reduced while the high tunability is kept, and the high-quality FOM is obtained and reaches 36.77. The film is excellent in performance and controllable in process, and has important application value in microwave communication devices such as tunable filters and phased array radars.

The invention discloses a capacitance setting method and device for a filter and a storage medium, and the method comprises the steps: calculating a working current flowing through a single-tuned filter under the condition that a harmonic wave is injected into the single-tuned filter; the single tuned filter comprises a capacitor and a reactor; calculating the rated capacity of the capacitor according to the working current; according to the rated capacity of the capacitor, calculating the rated voltage which can filter harmonic waves and is minimum in capacity for the capacitor; and setting the minimum capacity of the capacitor according to the rated voltage of the capacitor. According to the embodiment of the invention, the minimum capacity of the capacitor is calculated under the condition of keeping the harmonic filtering effect of the capacitor of the single-tuned filter, and the cost of the capacitor can be reduced, so that the cost of the single-tuned filter is reduced, and the cost is reduced on a large scale when a large number of low single-tuned filters are deployed in a power distribution network.

The present subject matter provides a method and apparatus for tuning an ANC based on a user hearing threshold level, in which hearing threshold level data of a user is obtained by performing a hearing test on the user, and an ANC filter is tuned based on the hearing threshold level data of the user, thereby enabling the user to obtain a more optimized ANC effect.

The invention discloses a mid-infrared narrow-band tunable filter based on a phase change material GST, and particularly relates to the technical field of micro-nano optical devices, the filter comprises a dielectric substrate layer and a double-rectangular super-structure grating layer which is located on the dielectric substrate layer and is periodically distributed; the double-rectangular super-structure grating layer comprises a first rectangular microstructure and a second rectangular microstructure which are arranged at a certain interval; the first rectangular microstructure is a Ge cuboid block; the second rectangular microstructure is composed of a Ge cuboid block similar to the first rectangular microstructure and a dielectric constant variable phase change material GST block embedded in the bottom of the Ge cuboid block. Tunability of the center wavelength position and the bandwidth of the filter is achieved through changes of the inclination angle of incident light and different phase states of GST, the requirement for dynamic regulation and control of a transmission spectrum is met, the utilization rate of the filter is greatly increased, and the tunable filter has the flexible tuning characteristic in practice.

Systems and methods here may include improved tunable lasers having a tunable filter and a tunable channel selector that can control precisely the wavelength and the bandwidth of the light emitted by the laser, while suppressing light that may otherwise be emitted by the laser outside the desired wavelength and bandwidth with unidirectional ring lasers having a resonator of which forms a ring and where light propagates only in one of the two possible directions.

The invention relates to the technical field of power grid harmonic suppression, in particular to a fundamental-loss-free low-parallel-resonance band-pass filter which comprises a first single-tuned filter Hn1 and a second single-tuned filter Hn2 which are arranged in parallel, and the series resonance frequencies of the first single-tuned filter Hn1 and the second single-tuned filter Hn2 are different. A group of resistors R1 is bridged between the first single-tuned filter Hn1 and the second single-tuned filter Hn2; the first single-tuned filter Hn1 comprises a first capacitor C11, a second capacitor C12 and a first reactor L1, the first capacitor C11, the second capacitor C12 and the first reactor L1 are connected in series, the second single-tuned filter Hn2 comprises a third capacitor C2 and a second reactor L2, and the third capacitor C2 and the second reactor L2 are connected in series; according to the invention, the structure is simple, the cost is low, the resistor R1 has no fundamental wave loss, the energy conversion efficiency of the whole power system is improved, the loss of energy in the transmission and treatment process is reduced, and the energy-saving effect is good.

The invention discloses a system and method for detecting the junction temperature of LD chips in batches in real time, the system comprises aging and testing equipment, an MEMS optical switch, an acousto-optic tunable filter and a PD, the aging and testing equipment comprises a plurality of aging testing modules, the system further comprises a real-time operation, processing and control unit RTOPCU, and the real-time operation, processing and control unit RTOPCU is connected with the MEMS optical switch, the acousto-optic tunable filter and the PD. The control module is also used for controlling the COS unit of each aging test module to output laser, controlling the switching from the multi-path optical fiber input of the MEMS optical switch to the single-path optical fiber output of the MEMS optical switch, and controlling the input voltage of the acousto-optic tunable filter; filtering the multi-wavelength laser output of the MEMS optical switch to obtain a single-wavelength laser output signal corresponding to the input voltage of the MEMS optical switch; synchronously receiving a PD output voltage value obtained by detecting, amplifying and converting the laser signal output by the tunable filter converted by the PD; and calculating the junction temperature of the current COS unit under the condition that the PD output voltage value is not less than the threshold voltage value.

The invention discloses a radio frequency front end of a radar receiver with a large dynamic range, relates to the field of wireless communication, and aims to solve the problem that a third-order intercept point and a noise coefficient are difficult to meet indexes under the condition that an existing receiver meets high sensitivity. The method comprises the following steps: a receiving calibration switch selects to input an antenna signal and a calibration signal into a preposed step attenuator, the antenna signal and the calibration signal enter a numerical control tuned filter after impedance matching by a matching circuit, an output tuned and filtered signal enters a low-noise amplifier, and the signal after low-noise amplification and a receiving gate enter a frequency mixer after being selected by a transceiving switch; and the weak intermediate-frequency signal is subjected to signal intensity adjustment through the first amplifier and the rear step attenuator in sequence, and is processed by the crystal filter and the amplifier twice to output the intermediate-frequency signal. Under the condition of high sensitivity, the optimal signal-to-noise ratio can be obtained, the noise coefficient is reduced, the influence on a channel third-order intercept point index is reduced, and the harmonic suppression degree of an intermediate-frequency signal is improved.

The present invention relates to a multi-parameter tunable filter based on a phase-change Bragg grating and a control method thereof. The filter comprises a substrate, a waveguide, a phase-change Bragg grating and a grating cover layer. The waveguide is arranged on the substrate, the phase-change Bragg grating is arranged on the waveguide, and the grating cover layer is arranged on the phase-change Bragg grating, wherein the phase-change Bragg grating adopts a phase-change material GSST. The phase-change Bragg grating of the present invention adopts the phase-change material GSST, utilizes the optical properties of the phase-change material GSST, has two optical pass characteristics of a passband and a stopband without changing the device structure, and can change the refractive index distribution of the phase-change Bragg grating by adjusting various parameters of the filter, thereby realizing the adjustment of the number of filter channels and the tunability of the transmittance bandwidth, so that it can be widely used in the field of optical communications.