14 results about "Stop band attenuation" patented technology

The application is suitable for the field of communication related technology, and provides a transponder transmission unit six-order band-pass filter circuit, which comprises a first-order circuit, a second-order circuit, a third-order circuit, a fourth-order circuit, a fifth-order circuit and a sixth-order circuit; and the multiple-order circuits in the filter circuit are connected in series in sequence. Compared with the original filter circuit, the above filter circuit has a narrower passband bandwidth of 3.8MHz~4.7MHz, effectively filters out interference signals, and has a better suppression degree with a stopband attenuation of about-100dB. The center frequency of the BTM device uplink signal is 4.234MHz±175KHz, and the frequency deviation is ±282KHz. After the interference signals are filtered out by the six-order band-pass filter circuit, the signal with a frequency range of 3.8MHz~4.7MHz is obtained, which is convenient for the transponder transmission unit to better demodulate the FSK signal.

The invention discloses an anti-symmetric filter design method based on an anti-auto-inverse matrix theory, and belongs to the technical field of digital signal processing. According to the method, a design problem of an antisymmetric filter is modeled into an optimization problem of an impulse response vector h, and an inverse self-inverse constraint h =-Jh (J is an inverse unit matrix) is applied, so that an optimization target minize | A -d | is constructed. An iterative solution technology of a generalized coupling Sylster transpose matrix equation is adopted, and through parameter initialization, residual matrix updating, step length dynamic adjustment and anti-auto-back projection operation, it is ensured that a filter coefficient strictly meets antisymmetry. Furthermore, the calculation complexity is reduced by using block calculation, fast multiplication and a precondition technology, and the frequency domain performance is optimized in combination with a weighted least square method and a Lagrange multiplier method. According to the filter designed by the invention, the strict linear phase characteristic is maintained, meanwhile, the stop-band attenuation can reach more than 50dB, the gradient of a transition band is improved by 30%, and the group delay fluctuation is controlled within 0.1 sampling point, so that the filter is suitable for medical image and radar signal processing and high-fidelity audio systems, and has the characteristics of high calculation efficiency and excellent performance.

The embodiment of the invention discloses a signal sampling method under arbitrary sampling rate conversion with designable frequency response. According to one specific embodiment, the method comprises the steps that a first discrete time signal is obtained, the first discrete time signal is collected by front-end equipment, and the front-end equipment correspondingly has a fixed signal sampling rate or a limited signal sampling rate; the first discrete time signal is filtered through a least square filter, a second discrete time signal is obtained, and a signal sampling interval corresponding to the first discrete time signal is different from a signal sampling interval corresponding to the second discrete time signal; the least square filter is a template filter which is constructed based on passband gain, stopband attenuation, passband cut-off rate and stopband starting frequency and is used for carrying out signal sampling at any sampling rate. According to the embodiment, the conversion of any sampling rate is realized, and the multi-sampling-rate signal processing requirement of the signal acquisition system is met.

The invention discloses a surface acoustic wave resonator and a manufacturing method thereof, a filter and a communication device, and the surface acoustic wave resonator comprises a piezoelectric material layer which comprises a first region and two second regions which are arranged in a first direction; the interdigital transducer is positioned on one side of the piezoelectric material layer; the two reflection electrode structures and the interdigital transducer are arranged on the same layer, the first area is located between the two second areas, the interdigital transducer is located in the first area, and the two reflection electrode structures are arranged in the two second areas in a one-to-one correspondence mode. The position, close to the interdigital transducer, of at least one reflection electrode structure is provided with a partial suspension electrode structure, the surface acoustic wave resonator can keep passband insertion loss, meanwhile, the stopband attenuation amount is increased, the isolation degree is improved, the size of the surface acoustic wave resonator is not increased, and the surface acoustic wave resonator can be applied to the field of acoustic wave resonators. And high end and miniaturization of the surface acoustic wave resonator are ensured.

This invention relates to the field of radar signal processing technology, and particularly to an MTD filter design method based on particle swarm optimization, comprising the following steps: S1: Obtaining the Doppler center frequency range and normalized half-width based on the radar type and clutter type to obtain constraints, and obtaining filter information based on the constraints and the global pilot vector matrix; S2: Designing a fitness function based on a nonlinear function and a hard-coded threshold; S3: Designing the filter based on the fitness function, and iteratively updating the filter using a main lobe width bisection method to obtain the optimal filter. This invention achieves optimized design by constructing linear and nonlinear multi-parameter fitness functions, while satisfying the requirements for stopband attenuation, null depth, and clutter bandwidth. Furthermore, it uses a bisection method for iterative optimization of the main lobe width, achieving high robustness under different clutter environments, improving the design efficiency of the MTD filter, reducing main lobe broadening, and lowering filter gain loss.

The application discloses a method, device and equipment for designing a channel filter and a computer storage medium, and relates to the technical field of wireless communication. The method comprises the following steps: acquiring a signal bandwidth, a baseband sampling rate, a frequency of adjacent channel interference, a noise power spectral density of adjacent channel interference and a noise power spectral density of a signal; calculating a normalized passband cutoff frequency, a normalized stopband cutoff frequency and a stopband attenuation according to the acquired parameters; determining a channel filter coefficient according to the normalized passband cutoff frequency, the normalized stopband cutoff frequency and the stopband attenuation, and obtaining a channel filter corresponding to the channel filter coefficient; inserting a preset value into the channel filter coefficient to obtain a target channel filter coefficient, updating the channel filter, and obtaining a target channel filter. The embodiment of the application realizes the design of a steep transition band channel filter while reducing the structural complexity.

Printed-line filter designs with wide bandwidth, low insertion loss, good stopband attenuation, independent control of low-side and high-side attenuation, and high selectivity. Embodiments include a printed-line pseudo-HPF design with such characteristics, and a printed-line cascaded BPF design which has approximately the same insertion loss as an equivalent single printed-line BPF filter but with greater ultimate stopband attenuation. One embodiment includes a printed interdigitated-line BPF including at least one coupling enhancement strip. Another embodiment includes a cascaded BPF including a low-pass filter and an electrically coupled printed interdigitated-line BPF including at least one coupling enhancement strip. The printed interdigitated-line bandpass filter includes a set of interdigitated resonator sections, each adjacent pair of interdigitated resonator sections being separated by an associated gap, wherein the at least one coupling enhancement strip is spaced from an associated gap separating an adjacent pair of interdigitated resonator sections in the set of interdigitated resonator sections.

The invention discloses an integral coefficient design method for a two-channel lattice orthogonal filter bank. According to the method, on the basis of direct quantization of continuous optimal coefficients, a quantization sequence criterion is provided, and descending sorting is carried out according to the sensitivity of lattice coefficients to serve as a quantization sequence. Secondly, using a low-pass analysis filter frequency point in a stop band range as a target function for quantizing a perfect reconstruction orthogonal filter bank, using a directly quantized lattice coefficient as an algorithm initial value, using Gurobi to optimize and solve, and minimizing the target function f for each frequency point; and performing first-order Taylor approximation on the target function to obtain a coefficient error value, and updating a lattice coefficient value based on a quantization sequence to complete lattice coefficient discretization. According to the method, the problem that the stop-band attenuation performance and the frequency selectivity are insufficient due to coefficient mantissa truncation and rounding in an existing quantization method is solved, and the obtained integral coefficient meets the perfect reconstruction characteristic of the two-channel lattice type orthogonal filter bank.

This application provides an adaptive suppression method, system, storage medium, and program product for inter-band interference of a multi-band common-aperture antenna, relating to the field of communication radio frequency signal processing technology. The method includes: acquiring the broadband radio frequency receiving assembly signal received by the multi-band common-aperture antenna; extracting the target coupling signal through a directional coupler; inputting the target coupling signal into a preset duplex frequency division network to filter out the first band signal of the desired service radio frequency carrier and extract the second band signal of the cross-band intermodulation leakage component; continuously sampling the second band signal using a logarithmic detector circuit to obtain a transient power level sequence and determine the power mutation gradient; dynamically attenuating and matching the current transient power level and power mutation gradient using a preset adaptive suppression function to obtain the target stopband attenuation coefficient; converting the target stopband attenuation coefficient into a digital-to-analog bias control voltage, and using the digital-to-analog bias control voltage to perform target adjustment operation on the adaptive stopband suppression circuit.

The invention discloses a laser interferometer high-precision filter coefficient generation method based on an FPGA, and belongs to the technical field of digital signal processing. The method comprises the following steps: designing an ideal floating point FIR filter coefficient according to a measurement requirement and carrying out initial quantization; constructing a cost function containing passband ripples and stopband attenuation weights; under the constraint of keeping linear phase symmetry, performing bit-by-bit perturbation and iterative search on integer coefficients, and searching an optimal integer coefficient set which minimizes a cost function; and generating a fixed-point coefficient file adaptive to the FPGA hardware resources. The invention provides a coefficient optimization strategy in a discrete space aiming at the problem that the performance of a filter is reduced due to the limited word length effect of an FPGA (Field Programmable Gate Array) in a laser interference measurement system. On the premise that FPGA hardware resource consumption is not increased, quantization noise is remarkably reduced, the stopband suppression degree and the signal-to-noise ratio of the filter are improved, and therefore the final measurement precision of the laser interferometer is improved.

The utility model discloses a thin film filter, which adopts a substrate with a larger dielectric constant so as to reduce the length of a resonator in the filter. A thinner substrate is adopted, so that the diameter of the metalized through hole is reduced; a stepped impedance resonator is adopted to replace a traditional resonator, and a wider stop band is achieved by adjusting the impedance ratio and the electrical length of the stepped impedance resonator; a microstrip line is arranged between the two stepped impedance resonators, so that the bandwidth and in-band fluctuation of the filter are reduced, and the stop-band attenuation is increased; the input tap and the output tap are fixed in the middle of the substrate, so that the layout of other components is facilitated, further miniaturization of the filter is realized, the coupling strength of the filter can be obviously reduced, and a narrow-band filter under high frequency is realized.

The invention relates to a band-pass filtering method and circuit for a depth finder. According to the method, two stages of MFB type band-pass filters with different center frequencies are cascaded to process underwater acoustic echo signals, the center frequency of the first stage is 432 kHz, the center frequency of the second stage is 476 kHz, two-stage filtering is executed by two channels integrated in the same dual-channel operational amplifier chip, and passband flatness and rapid stop-band attenuation are achieved through parameter collaborative setting. A corresponding circuit adopts an OPA2830 operational amplifier, and through optimized resistor-capacitor network configuration, the area of a printed board is remarkably reduced, the wiring complexity and cost are reduced, and meanwhile, the filtering consistency and the anti-interference capability are improved. According to the scheme, noise interference in signals received by the depth finder can be effectively filtered out, the signal-to-noise ratio is remarkably improved, and the accuracy and reliability of water depth measurement are guaranteed.

The invention relates to the technical field of integrated circuits, and discloses a 5G baseband signal processing method based on an ASIC (Application Specific Integrated Circuit). The method comprises the following steps: receiving a 5G wireless signal and converting the 5G wireless signal into a digital baseband signal stream, and generating an initial waveform sampling sequence; performing multi-dimensional feature extraction on the sequence, and separating a time domain feature vector and a frequency domain feature matrix; dynamically configuring a cut-off frequency parameter of the first filter according to a peak fluctuation interval in the time domain feature vector; and adaptively adjusting the stopband attenuation depth of the second filter based on the subcarrier energy distribution in the frequency domain characteristic matrix. And when it is detected that the synchronization deviation between the time domain feature vector and the frequency domain feature matrix exceeds a tolerance threshold, activating a waveform reconstruction engine to generate a compensation coefficient. And loading the compensation coefficient to a register block of the ASIC, and correcting the waveform distortion component of the digital baseband signal flow in real time. According to the invention, the adaptability of the system to the complex signal environment is enhanced, and the stability and accuracy of the signal in the transmission process are ensured.

This invention relates to the field of filter technology, and particularly to a design method, system, device, and medium for a quasi-completely reconstructed filter bank. The method first uses a generalized monotonic asymptotically saturated function as the initial value of a prototype filter, substituting it into the filter bank model for optimization to obtain a baseline fully reconstructed prototype filter. Then, a transition band adjustment parameter is introduced to perform an analytical mapping transformation on the amplitude-frequency response of the baseline fully reconstructed prototype filter, resulting in a fully reconstructed prototype filter with optimized transition band. Finally, combined with a determined number of filter bank channels and the polyphase decomposition length of the prototype filter, a quasi-completely reconstructed prototype filter is obtained through frequency domain sampling and transformation processing, which is then modulated to obtain a quasi-completely reconstructed filter bank. This method, by introducing a generalized monotonic asymptotically saturated function as the initial value of the prototype filter and combining it with the analytical mapping mechanism of the transition band adjustment parameter, significantly improves stopband attenuation performance and increases the efficiency of prototype filter coefficient generation while ensuring quasi-complete reconstruction.