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57 results about "Chebyshev filter" patented technology

Chebyshev filters are analog or digital filters having a steeper roll-off and more passband ripple (type I) or stopband ripple (type II) than Butterworth filters. Chebyshev filters have the property that they minimize the error between the idealized and the actual filter characteristic over the range of the filter (See references eg. [Daniels],[Lutovac]), but with ripples in the passband. This type of filter is named after Pafnuty Chebyshev because its mathematical characteristics are derived from Chebyshev polynomials. The type I Chebyshev filters are called usually as just "Chebyshev filters", the type II ones are usually called "inverse Chebyshev filters".

Direct and integrated design method of band-pass filters

InactiveCN102708265AImproved group delay characteristicsThe method is simple, fast and accurateSpecial data processing applicationsTransmission zerosBand-pass filter
The invention discloses a direct and integrated design method of band-pass filters. In order to overcome the defect that the coupling matrix derived from the traditional integrated design method of the generalized Chebyshev single-pass-band or multi-pass-band band-pass filters is only narrow-band approximation and can not be used for integrated band-pass filters, the method is available for integrating the generalized Chebyshev single-pass-band or multi-pass-band band-pass filters in a band-pass domain directly, and improving the group delay characteristic in the pass band of the filter by introducing a plurality of transmission zeros. The direct and integrated design method can be used for extracting a network matrix of the generalized Chebyshev band-pass filters of the transmission zeros which have any bandwidth and are positioned at any frequency; and the derived network matrix has practical physical significance, while the network matrix derived from the traditional scheme can be taken as a low-pass narrow-band approximation result of the network matrix derived by using the method disclosed by the invention. The whole method disclosed by the invention has the advantages of simpleness, fastness and accuracy.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Generalized Chebyshev filter integrated design method based on conformal transformation

The invention relates to a generalized Chebyshev filter integrated design method based on conformal transformation. The method comprises the steps of Step 1, constructing a characteristic function in a z region; Step 2, deriving polynomials from the characteristic function according to indexes; Step 3, converting polynomials and scattering parameters formed by the polynomials into admittance parameters; Step 4, conducting partial fraction expansion on the admittance parameters, and contrasting the admittance parameters with corresponding admittance parameters in a transverse equivalent circuit, so that corresponding parameters such as coupling coefficients and resonant frequencies can be determined, and a network matrix which is represented in a global resonance mode can be obtained; and Step 5, converting the network matrix which is represented in the global resonance mode into a desired sparse topological structure through multiply transformation, rotation transformation and the like. Compared with the prior art, the method has the advantages that generalized Chebyshev band-pass filters of any bandwidth can be synthesized, transmission zero can be located at any limited frequency or an infinity position, and the method is simple and easy to implement.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Direct integrated design method for random-bandwidth multi-pass-band generalized Chebyshev filter

The invention relates to a direct integrated design method for a random-bandwidth multi-pass-band generalized Chebyshev filter. The method comprises the following steps of: 1, according to indexes of an analog filter to be integrated, performing independent integrated design on each pass band according to single-pass-band filters, and deriving a characteristic function and a polynomial, which correspond to each single-pass-band filter; 2, substituting the characteristic functions and the polynomials into a superposition relational expression, deriving the corresponding polynomials and determining final characteristic functions of the analog filter to be integrated; 3, converting a scattering matrix which is formed by the polynomials into a theoretic admittance matrix; and 4, performing partial fraction expansion on the theoretic admittance matrix which is obtained in the step 3, and thus obtaining a transverse network matrix of the analog filter to be integrated, which is represented in a global resonant mode. The direct integrated design method for the random-bandwidth multi-pass-band generalized Chebyshev filter has the advantages that network matrixes of various topological equivalent circuits for realizing the frequency response of the analog filter to be integrated can be directly derived, and final physical implementation is facilitated.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Wilkinson power divider with isolation frequency point aligned Chebyshev filtering characteristics and a preparation method thereof

The invention discloses a Wilkinson power divider with isolation frequency point aligned Chebyshev filtering characteristics, which comprises an input end and two output ends, and also comprises two transmission branches connected in parallel between the input end and the two output ends; Each transmission branch is formed by connecting n sections of first transmission lines and one section of second transmission line in series; Wherein the second transmission line is selectively connected to the starting end or the tail end of the transmission shunt; The plurality of resistors are respectively connected between every two corresponding sections of transmission lines on the two transmission branches; The two groups of short-circuit wires are symmetrically connected to the two transmission branches; Each group of short-circuit lines comprises m short-circuit lines, and m is greater than or equal to 2 and less than or equal to n; When m is an even number, the short-circuit lines are connected to symmetrical positions on the two sides of the center of the n sections of first transmission lines; And when m is an odd number, the short circuit lines are connected to the central positionsof the n sections of first transmission lines and the symmetrical positions on the two sides of the central positions. The invention also provides a preparation method of the power divider.
Owner:JILIN UNIV

Impedance transformer with Chebyshev filter property of multi-order transmission lines and short-circuited lines, and preparation method

The invention discloses an impedance transformer with Chebyshev filter property of multi-order transmission lines and short-circuited line. The impedance transformer comprises an input end unit and anoutput end unit, impedance transformation units serially connected between the input end unit and the output end unit in order through the multi-order transmission lines, and short-circuited lines, wherein the amount of the short-circuited line is not more than that of the multi-order transmission line; when the multi-order transmission lines are in the odd-order, the number of the short-circuitlines is odd segments and the short-circuited lines are symmetrically distributed at two sides of the center of the multi-order transmission lines; when the multi-order transmission lines are in even-order and the number of the short-circuited line is even segments, the short-circuited lines are symmetrically distributed at two sides of the center of the multi-order transmission lines; when the multi-order transmissions lines are in even-order and the number of the short-circuited line is odd segments, a segment of short-circuited line is arranged at the center of the multi-order transmissionlines, and the rest short-circuited lines are symmetrically distributed at two sides of the center of the multi-order transmission lines. The invention further provides a preparation method of the impedance transformer with Chebyshev filter property of the multi-order transmission lines and short-circuited lines.
Owner:JILIN UNIV

Leakage current detecting fast protection circuit and protection method

The invention discloses a leakage current detecting fast protection circuit in the field of power electronics. The leakage current detecting fast protection circuit comprises a current transformer installed on a loop to be tested. A secondary side output winding of the current transformer is connected with both ends of a self-excited oscillator. An output end of the self-excited oscillator is connected with an input end of the fast protection circuit. An input end of the self-excited oscillator is connected with a non-ground end of a sampling resistor, and at the same time, the non-ground endof the sampling resistor is connected with an input end of a Chebyshev filter. An output end of the Chebyshev filter is connected with an input end of a sampling conditioning unit. The sampling conditioning unit includes a signal voltage dividing resistor and an operational amplifier. The output end of the Chebyshev filter is connected with one end of the signal voltage dividing resistor, and theother end of the signal voltage dividing resistor is connected directly with an output end of the fast protection circuit and an in-phase input end of the operational amplifier in the sampling conditioning unit. An output end of the sampling conditioning unit is connected with a controller. The leakage current detecting fast protection circuit of the invention is safer and more rapid when detecting a large leakage current, and can be used in photovoltaic grid-connected power generation.
Owner:YANGZHOU UNIV

Wind turbine generator wide-frequency-band additional damping control method

The invention provides a wind turbine generator wide-frequency-band additional damping control method which comprises the steps of carrying out oscillation mode decomposition through Chebyshev filtersof different frequency bands and according to the rotating speed difference of a draught fan, and obtaining the oscillation components of all the frequency bands; respectively carrying out adaptive variational mode decomposition on the oscillation component of each frequency band to extract an oscillation mode signal of each frequency band; respectively carrying out a Prony algorithm on the oscillation modal signals of each frequency band to extract the oscillation modal parameters of each frequency band; according to the oscillation modal parameters of each frequency band, based on a lead-lag correction model, performing optimization calculation by using a quantum particle swarm algorithm to obtain the optimization control parameters of damping control of each frequency band; integratingthe output of the additional damping controllers of multiple frequency bands, and superposing the final control quantity to a current inner loop controlled by a wind turbine generator, thereby inhibiting different oscillation modes. according to the method, the damping controllers are designed respectively, so that the independence of different types of damping functions is ensured, and the crossinfluence of different types of damping inhibition is reduced.
Owner:YUNNAN POWER GRID CO LTD ELECTRIC POWER RES INST

Reconfigurable Amplifier and Filter Using Time-Varying Circuits

A reconfigurable system is used for amplifying, filtering, and sampling analog signals. Unlike conventional analog filters and amplifiers based on linear time-invariant systems and classical filter responses such as Butterworth or Chebyshev filters, the system described here uses parallel branches comprising time-varying circuits. An input voltage or current is communicated to a number of parallel branches and each branch processes a segment of the input signal using time-varying circuits such as analog multipliers and/or super-regenerative amplifiers. The time-window of the input signal processed by each branch is equal in length, but offset in time from all other branches. The output of each branch is a series of filtered and amplified samples of the input signal. The output samples of all branches are then time-interleaved in the analog domain, or digitized using separate analog-to-digital converters and then time-interleaved digitally. By using time-varying circuits, sharper filters and greater amplification is achieved while consuming less integrated-circuit area and power. The time-varying circuits in each branch are controlled by synthesized signals that determine the filter response and gain of the overall system. As a result, better flexibility and reconfigurability are achieved compared with classical filters and amplifiers.
Owner:T VAR SEMICON

Third-order filtering base station antenna based on resonator type dipole

The invention discloses a third-order filtering base station antenna based on a resonator type dipole. The third-order filtering base station antenna comprises a first vertical dielectric plate, a second vertical dielectric plate and a horizontal dielectric plate, wherein the first vertical dielectric plate is provided with a first resonator and a first copper-clad structure, the first copper-cladstructure and the first resonator form a first dipole, and 45-degree polarization feed is realized by a first feed port through a second resonator, a third resonator and a first coupling feed line onthe first vertical dielectric plate and the horizontal dielectric plate; a fourth resonator and a second copper-clad structure are arranged on the second vertical dielectric plate, a second dipole isformed by the second copper-clad structure and the fourth resonator, and 45-degree polarization feed is realized by a second feed port through a fifth resonator, a sixth resonator and a second coupling feed line on the second vertical dielectric plate and the horizontal dielectric plate; The antenna is advantaged in that dual polarization of the antenna is achieved, the filtering characteristic of a three-order Chebyshev filter is achieved, the polarization isolation degree is 20dB or above, and meanwhile the antenna has the advantage of being low in machining cost.
Owner:SOUTH CHINA UNIV OF TECH

Filter and transmission zero point adjustment method therefor

ActiveCN105680124AReduce physical sizeSolving for asymmetric distributionsWaveguide type devicesCouplingTransmission zeros
The invention provides a filter, which comprises a main path of the filter and an energy absorbing and coupling unit, wherein the energy absorbing and coupling unit is connected to an input end and an output end in an additional coupling manner; and the energy absorbing and coupling unit comprises two resonators which are the same or similar in frequency and have couplings. The filter provided by the invention can directly generate a pair (two) of transmission zero points through first-order additional coupling, or even generate multiple pairs of transmission zero points, so that the physical size of the filter can be greatly reduced; and meanwhile, the key problem that the filter does not have a cross coupling, but can achieve the transmission zero points of the filter is also solved. Asymmetrical distribution of the transmission zero points can also be achieved by properly adjusting the frequencies of various resonators in the energy absorbing and coupling unit; and the problem of random distribution of the transmission zero points is solved. Meanwhile, the filter provided by the invention does not have limitation on the resonator structure, so that all resonators can adopt the same shape, do not need to introduce a coupling intersection line; and the whole design process is like the design process of a traditional chebyshev filter and becomes relatively simple.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Direct and integrated design method of band-pass filters

InactiveCN102708265BImproved group delay characteristicsThe method is simple, fast and accurateSpecial data processing applicationsTransmission zerosBand-pass filter
The invention discloses a direct and integrated design method of band-pass filters. In order to overcome the defect that the coupling matrix derived from the traditional integrated design method of the generalized Chebyshev single-pass-band or multi-pass-band band-pass filters is only narrow-band approximation and can not be used for integrated band-pass filters, the method is available for integrating the generalized Chebyshev single-pass-band or multi-pass-band band-pass filters in a band-pass domain directly, and improving the group delay characteristic in the pass band of the filter by introducing a plurality of transmission zeros. The direct and integrated design method can be used for extracting a network matrix of the generalized Chebyshev band-pass filters of the transmission zeros which have any bandwidth and are positioned at any frequency; and the derived network matrix has practical physical significance, while the network matrix derived from the traditional scheme can be taken as a low-pass narrow-band approximation result of the network matrix derived by using the method disclosed by the invention. The whole method disclosed by the invention has the advantages of simpleness, fastness and accuracy.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
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