65 results about "Tuned filter" patented technology

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.

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 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 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.

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 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 present application relates to a kind of multi-band reconfigurable fourier mode-locked optoelectronic oscillator, its structure includes laser, electro-optic modulator, photodetector, first A low noise amplifier, first multiplexer, second multiplexer, filter amplification branch, arbitrary waveform generator and electric power divider etc., wherein, first multiplexer, second multiplexer, the N filter amplification branches connected therebetween and arbitrary waveform generator jointly constitute multi-band reconfigurable filter module.The present application sets up multiple filter amplification branches in optoelectronic feedback oscillation loop, thereby constructs a multi-band fourier mode-locked oscillation loop cavity, the frequency range and period of multi-band reconfigurable microwave signal are determined by the sweep width and period of tunable filter in each filter amplification branch in multi-band reconfigurable filter module.Thereby for anti-radar or anti-jamming communication system provides a high-quality microwave signal source.

The invention discloses a tunable mid-infrared fiber laser with high power flatness. A pumping source enters an erbium-doped fiber through a pumping / signal coupler, and a low-reflectivity cavity mirror, the erbium-doped fiber, a laser collimator and a tuned filter form a laser resonant cavity; the low-reflectivity cavity mirror and the pumping / signal coupler are coupled to output intermediate infrared laser, the tuning filter device is used for realizing a wavelength tuning function, and the insertion loss difference value of the device under different working wavelengths is less than 0.5 dB; the wavelength of the pumping source is in a 1.6-1.7 micron wave band, erbium ions are pumped from a ground state energy level to a laser upper energy level, and laser lower energy level particles are consumed; the stable insertion loss in the process of adjusting the working wavelength by using a tuning filter device is combined with the characteristics that the emission cross section and the absorption cross section of erbium ions are gradually reduced along with the increase of the wavelength and the reduction rate of the absorption cross section is greater than that of the emission cross section, so that the gain difference caused by the emission cross section difference under different laser wavelengths of the fiber laser is reduced; and the power flatness of the fiber laser under different tuning wavelengths is improved.

The utility model discloses a structure for solving synchronous tuning of a coaxial mechanically tuned filter, which belongs to the technical field of microwave filters and comprises five parallel coaxial cavities, tuning rods in the coaxial cavities, double-coupling hole structures between adjacent cavities and input and output structures. The cavity bodies of the five parallel-row coaxial cavities are the same in size and are symmetrically distributed, the number of the cavity bodies can be N, and the coaxial cavity bodies can be arranged in a parallel-row mode or other flexible modes. The tuning rods in the coaxial cavity are symmetrically distributed, the diameters of the tuning rods are different, the middle of the tuning rods is thick, and the two sides of the tuning rods are thin. The double-coupling junction hole structure between the adjacent cavities is formed by forming two regular coupling holes in the common wall of the adjacent cavities, and the coupling between the whole cavities is symmetrically distributed. By changing the diameter of the resonance rod in the coaxial cavity, the problem of asynchronous high-frequency mechanical tuning is solved, and meanwhile, the bandwidth difference in the whole tuning range can be reduced by adopting the double coupling holes.

The application discloses a parameter design method of a double-tuned filter with damping, and belongs to the technical field of power quality treatment, comprising the following steps: determining the design reactance range of the double-tuned filter under each frequency band according to the harmonic range required to be filtered out by a target power grid area; selecting the optimal parameters of the inductance and the capacitance of the double-tuned filter with the lowest cost as the target; selecting the optimal damping parameters based on the optimization requirements of the load and the energy loss, and determining the final parameter design scheme. The parameter design method of the double-tuned filter with damping can reduce the energy loss as much as possible under the condition of guaranteeing a low harmonic level and a low component cost, realize the parameter design of the double-tuned filter, and has the advantages of low cost, low loss, convenient calculation, high practicability and high reliability.

The invention discloses a giant magnetostrictive micro-strain unit, a tunable filter and a passband adjusting method, and belongs to the technical field of electronic devices and radio frequency communication. The giant magnetostrictive micro-strain unit is composed of an outer conductor, an inner conductor, a supporting structure and a driver. The driver is composed of a giant magnetostrictive material, an output structure, a framework, a coil and a fixing structure. The tunable filter comprises a plurality of giant magnetostrictive micro-strain units; according to the filter, the current input into the coil is controlled, the driving magnetic field of the giant magnetostrictive material is changed, and the giant magnetostrictive effect of the giant magnetostrictive material is utilized to enable the giant magnetostrictive material to generate micro-strain, so that the structure of the filter is adjusted to adjust the characteristics of the filter; the position of the inner conductor in the outer conductor is adjusted by adjusting the micro strain of a driver at the bottom of the micro coaxial inner conductor, so that the loss and out-of-band rejection characteristics are adjusted; the length of the resonant transmission line is adjusted by adjusting the micro-strain of the driver at the end part of the resonant transmission line, so that the resonant frequency and the bandwidth are adjusted.

A self-tuning, resonant cavity transmitter combiner joins multiple RF transmitters and combines their signals onto a single transmission line. An additional tuning element is added to the junction of the signal paths to overcome the bandwidth limitations of the transmission lines joining the signal paths. An algorithm was developed to optimize the RF performance of the combiner by sampling the RF signals at various points in the RF circuit.

One example includes an acoustic resonator filter system. The system includes a plurality of filter blocks. Each of the filter blocks can include a plurality of tunable filter elements. Each of the tunable filter elements can include an acoustic resonator. The system also includes a switching network that receives a radio frequency (RF) input signal and provides a filtered RF output signal. The switching network can be configured to selectively switch at least one of the filter blocks in a signal path of the RF input signal to provide the RF output signal.

A tunable optical filter with a top-hat pass band shape. The proposed tunable optical filter is adapted to be installed over a top surface of a sensor, and comprises a set of at least three stacked dielectric mirrors parallelly adjacent to the plane of installation of the sensor, the at least three stacked dielectric mirrors comprise an upper mirror, an intermediate mirror and a lower mirror, wherein the set of at least three stacked mirrors is spaced within a variable distance to create at least two independent and adjacently equal volumetry cavities between the upper mirror and the intermediate mirror and between the intermediate mirror and the lower mirror.

The invention discloses a reliable direct-type identification method for characteristic parameters of a single-tuned filter, which comprises the following steps of: initializing the single-tuned filter to be detected to be in a zero state, applying a direct-current excitation source with constant amplitude to the single-tuned filter to be detected, sampling, storing a current sequence of the single-tuned filter, carrying out sliding mean filtering processing on a sample, and carrying out direct-current identification on the characteristic parameters of the single-tuned filter. Calculating an identification element, calculating an identification basic parameter, calculating an identification characteristic quantity, and obtaining the characteristic parameters of the single-tuned filter, such as resistance R, inductance L and capacitance C; 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 in the interference environment can be accurately and reliably estimated.

A receiver system has at least one antenna that receives a plurality of signals, including a desired signal, across a wide band of frequencies. At least one tunable filter is in signal communication with the at least one antenna, and filters the plurality of signals to produce a plurality of filtered signals. Gain control circuitry is in signal communication with the at least one tunable filter, and produces a gain adjusted version of the filtered signals. A processing unit processes received signals in a portion of the wide band to extract signal characteristics of at least one undesired signal in the portion of the wide band. The at least one tunable filter is tuned based at least in part on the signal characteristics of the at least one undesired signal to maintain the SNR of the desired signal above a threshold level at the output of the gain control circuitry.

The invention discloses a superconductive multi-path coupler based on an impedance traction network. Comprising a common end, a first tunable filter circuit, a second tunable filter circuit and a plurality of impedance traction networks, and the first tunable filter circuit comprises a first branch knot and a plurality of first tunable filters arranged on the first branch knot; the second tunable filter circuit comprises a second branch knot and a plurality of second tunable filters arranged on the second branch knot; and at least one of the signal input end and the signal output end of each first tunable filter and each second tunable filter is provided with an impedance traction network for adjusting the port reactance of the first tunable filter and the second tunable filter. The impedance traction network is arranged at the signal input end and / or the signal output end of the first tunable filter and the second tunable filter, and the port reactance of the first tunable filter and the second tunable filter can be adjusted on line, so that the passband return loss performance of the multi-path coupler is improved.

The invention relates to an acousto-optic tunable filter (Acoustical-optical tunable filter-AOTF), which is an electrically controlled tunable spectrum light splitting device, and is characterized in that the acousto-optic tunable filter (Acoustical-optical tunable filter-AOTF) is an electrically controlled tunable spectrum light splitting device. In a complex task, single-band information is often insufficient to support a decision, so that the invention provides a design method of a single transducer-dual-band acousto-optic tunable filter, a numerical calculation model is established through a dual-band wave vector geometry principle, and a dual-band tuning relationship under different cutting types is obtained. And furthermore, the design of the dual-band AOTF device with high diffraction efficiency and low power consumption is realized through the size optimization design of the transducer. Compared with an existing AOTF device design method, the single-transducer-dual-waveband AOTF device design method can utilize a single simple single-transducer AOTF device to obtain dual-waveband spectral data at the same time, the spectral range is expanded, the spectral detection efficiency is improved, and the detection capacity for a dynamic target is improved. Meanwhile, the dual-band detection can reduce the frequency of electrical power loading of the transducer, the thermal load of the device is reduced, and the working stability of the device is improved.

The present invention relates to a tunable filter bank for enhancing out-of-band suppression, comprising: 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, second, third, and fourth path switching modules are sequentially connected, the first filter bank is connected between the first and second path switching modules, and the second filter bank is connected between the third and fourth path switching modules. The circuit can be equivalent to one or more of a high-pass filter, a low-pass filter, a transmission line, and a bandpass filter, capable of processing signal waveforms in different frequency bands, and exhibiting high control accuracy and high reliability.

The invention provides an acousto-optic tunable filter device and an optical processing mechanism. The acousto-optic tunable filter device comprises an acousto-optic acting medium; the radio frequency array comprises a plurality of radio frequency assemblies and is arranged on the first side of the acousto-optic interaction medium, the radio frequency assemblies are suitable for emitting radio frequency signals in a working state, and the radio frequency signals excite sound wave signals in the acousto-optic interaction medium to form an acoustic grating; wherein the number of the radio frequency components in the radio frequency array is changed to change the effective action length of the acoustic grating in the acousto-optic action medium, so that the spectral resolution of the acousto-optic tunable filter is adjusted.

Various aspects include a wearable audio device with active noise reduction (ANR), wherein the ANR device includes: a feedback microphone; an electroacoustic transducer; and a feedback compensator configured to output a noise reduction signal to the electroacoustic transducer in response to a feedback signal from the feedback microphone, wherein the feedback compensator includes a tunable filter that modulates a loop gain in response to detecting an adverse low-frequency event in the noise reduction signal output from the tunable filter, wherein the tunable filter is configured to maintain a substantially similar loop gain shape near a low-frequency crossover when the low-frequency crossover varies during loop gain modulation.

The application discloses a specified harmonic compensation method of a hybrid active filter, which simulates a virtual capacitor for a voltage source inverter in a harmonic domain, and the capacitor value can be adaptively adjusted by a perturbation and observation method, so that the LC filter and the virtual capacitor can generate series resonance at a specified harmonic frequency, and the effect of a multi-tuned filter is achieved, thereby greatly improving the filtering characteristic of the LC single-tuned filter; the control method has the advantages of simple control structure, easy implementation and good filtering effect.

The application belongs to the field of femtosecond laser technology, and particularly relates to a few-cycle high-energy fiber chirped pulse amplification system and method. The system comprises a seed source module, a chirped pulse amplification module and a hybrid compression module. The seed source module adopts a nonlinear polarization rotation mode-locked resonator with an integrated tunable filter to generate linear chirped wide spectrum seed pulses with tunable central wavelength. The chirped pulse amplification module realizes energy amplification while effectively suppressing gain narrowing effect through a three-stage structure of pre-chirp management, pre-amplification and main amplification. The hybrid compression module adopts a cascaded scheme of a diffraction grating compressor and a fiber soliton self-compressor to finally compress the pulse width to two optical periods. The application solves the problem that high energy and few cycles are difficult to be considered in a C-band fiber amplification system, and can output high peak power pulses of hundreds of nanojoules and two optical periods.

The invention relates to the technical field of liquid crystal materials, and particularly discloses an isothiocyanate liquid crystal compound, a liquid crystal composition containing the isothiocyanate liquid crystal compound and a high-frequency assembly. The liquid crystal compound is a compound as shown in the following formula I, and Q1 represents O, S or Se. The main ring of the molecular structure of the liquid crystal compound provided by the invention contains a benzofuran, benzothiophene or benzoselenophene structure, and the liquid crystal compound with the specific structure has the advantages of higher clearing point, lower dielectric loss, higher dielectric tuning rate tau and higher quality factor eta. The liquid crystal composition containing the organic compound also has a higher clearing point, lower dielectric loss, higher dielectric tuning rate tau and a higher quality factor eta, and can be used for developing components and devices which are applied in a microwave range and have a high-frequency technology; the invention particularly relates to a microwave phase shifter, a tunable filter, a tunable metamaterial structure and an electronic beam control antenna. I.

The present invention provides an optical receiving device and an optical receiving module having a tunable wavelength filter. [Solution] The optical receiving device includes a thermoelectric element 320 arranged on a substrate 310, a first tunable wavelength filter 330 with one end positioned on one side of the thermoelectric element and the other end positioned lower and inclined than the plane of the thermoelectric element, which transmits only a first wavelength that varies according to the temperature of the thermoelectric element, a second tunable wavelength filter 350 positioned above the first tunable wavelength filter and spaced apart on one side of the thermoelectric element, which transmits only a second wavelength that varies according to the temperature of the thermoelectric element, a first detector 360 positioned on the substrate at a distance from the thermoelectric element and on the optical axis of the received signal, which detects signals that pass through both the first tunable wavelength filter and the second tunable wavelength filter, and a second detector 370 positioned at a distance from the first detector on the substrate and which detects signals that have passed through the second tunable wavelength filter and are reflected by the first tunable wavelength filter.

The invention relates to a tunable F-P filter based on capacitance micro-displacement detection and a control method, and aims to solve the technical problems of low adjustment precision and stability of an interference cavity in the prior art. According to the tunable F-P filter based on capacitor micro-displacement detection, the reference capacitor and the five detection capacitors are arranged, two of the five detection capacitors form a differential circuit used for detecting the X-direction parallelism change of an interference cavity, and the other two detection capacitors form a differential circuit used for detecting the Y-direction parallelism change of the interference cavity. And the rest detection capacitor is adjacent to the reference capacitor, and the detection capacitor and the reference capacitor form a differential circuit which is used for detecting the Z-direction cavity length change of the interference cavity, so that the detection direction of the interference cavity is consistent with the adjustment direction of the piezoelectric ceramic to the interference cavity, and high-precision adjustment and high stability of the interference cavity are realized.

A tunable filter (40; 50; 60; 70; 80; 80'; 90; 130) with tunable suppression, comprising: a first inductor (L1); a second inductor (L2) mutually coupled to the first inductor (L1), wherein the first inductor (L1) is connected in series with the second inductor (L2); and a tunable capacitor circuit (42; 52; 62; 72; 74; 92) which is electrically connected in parallel to the first inductor (L1) which has a switch (S11, S12, ..., S1N; S21, S22, ..., S2N; S31, S32, ..., S3N; S41, S42, ..., S4N; S51, S52, ..., S5N) and which is designed to match at least two notches in the frequency response of the tunable filter by changing a switching state of the switch (S11, S12, ..., S1N; S21, S22, ..., S2N; S31, S32, ..., S3N; S41, S42, ..., S4N; S51, S52, ..., S5N), wherein the tunable filter is designed to filter a high-frequency signal.

A system is provided herein. The system includes an electro-optic modulated (EOM) comb generator including an opto-electronic oscillator (OEO) loop to modulate a continuous-wave seed source and form an EOM comb, a saturable absorber to perform non-linear pulse shaping of the EOM comb, and a tunable filter having resonances matching a frequency spacing of the EOM comb. The tunable filter filters the EOM comb from the saturable absorber to provide an output EOM comb.