7results about How to "Improve filtering performance" patented technology

The invention discloses an anti-interference filter based on FFT (Fast Fourier Transform), and relates to the field of GNSS (Global Navigation Satellite System) receivers. A radio frequency front end is used for receiving GNSS signals and down-converting the GNSS signals into IF (Intermediate Frequency); the analog-to-digital converter ADC is used for converting the GNSS signal which is received by the radio frequency front end and moved to the intermediate frequency into a digital signal; and the anti-interference filter is used for converting the digital signal from time domain representation to frequency domain representation, eliminating an interference signal in a preset frequency range in a frequency domain according to a preset demand index, and inversely transforming the frequency domain signal subjected to interference elimination back to the time domain. The invention further discloses an interference suppression method of the anti-interference filter based on the FFT, the anti-interference filter based on the FFT is suitable for various GNSS receivers, the anti-interference performance of the receivers can be effectively improved, and the accuracy of navigation and positioning is ensured.

The application provides a low-profile duplex filter antenna and belongs to the technical field of wireless energy transmission.The low-profile duplex filter antenna comprises an upper metal floor, a dielectric substrate, a lower metal floor, a cavity column, a perturbation via and a suppression via; the lower metal floor is arranged on the lower surface of the lower dielectric substrate; the upper metal floor is arranged on the upper surface of the dielectric substrate; the cavity column penetrates through the upper metal floor, the dielectric substrate and the lower metal floor and surrounds a substrate integrated waveguide cavity; the perturbation via and the suppression via penetrate through the upper metal floor, the dielectric substrate and the lower metal floor; a cross-shaped groove is etched in the center of the upper metal floor; two complementary split ring resonator grooves with different diameters are etched at the connection between the circular cavity and the two side rectangular cavities of the upper metal floor; two feed lines are led out from the two ends of the upper metal floor. The antenna has the characteristics of low profile, is easy to integrate, and simultaneously reduces the manufacturing cost of the antenna and facilitates processing and manufacturing.

The application belongs to the field of microwave technology and discloses a reconfigurable differential filter based on HMCSIW, which comprises a first layer metal layer, a first layer dielectric layer, a second layer metal layer, a second layer dielectric layer and a third layer metal layer, the first layer metal layer is composed of a rectangular patch of a half-mode combline, a pair of trapezoidal microstrip lines, a pair of open-circuit microstrip stubs and a DBCSRR structure, the second layer metal layer is composed of a rectangular slot and a folded SSPPs structure and is a common ground of the structure, and the third layer metal layer is completely consistent with the structure size of the first layer metal layer. The length of the open-circuit stubs connected in parallel on the HMCSIW is controlled by the conduction and shutdown of the PIN diode, so that the resonant frequency of the open-circuit stubs is controlled, then the low-frequency zero point of the filter will change, and the bandwidth and center frequency of the entire filter will change accordingly. The filter can be reconfigured and combined with the differential transmission line, and has a common-mode rejection characteristic.

The application discloses a common-mode and differential-mode integrated inductor, which comprises a common-mode magnetic core, a differential-mode magnetic core, a first coil and a second coil. The common-mode magnetic core comprises a main magnetic ring. The differential-mode magnetic core is arranged on the outer periphery of the main magnetic ring. The first coil comprises a first inverted U-shaped body which is arranged on one side of the main magnetic ring and has one end downwardly extended into the inner ring hole of the main magnetic ring and the other end downwardly extended along the outer side of the main magnetic ring. The second coil comprises a second inverted U-shaped body which is arranged on the other side of the main magnetic ring and one side of the differential-mode magnetic core and has one end downwardly extended into the inner ring hole of the main magnetic ring and the other end downwardly extended into the inner ring hole of the differential-mode magnetic core. Thus, through the optimization design of the magnetic core structure and the coil, the good balance of the common-mode inductance and the differential-mode inductance performance is realized, the common-mode and differential-mode electromagnetic interference signals in the power supply circuit can be effectively inhibited, the electromagnetic compatibility of the power supply circuit is improved, and the stable operation of the electronic equipment is ensured.

The present invention discloses a high-performance active low-pass filter, which relates to high-frequency communication front-end equipment. This solution is proposed to solve the shortcomings of the prior art, such as weak stopband suppression, poor stability, and insufficient bandwidth. A first MOS capacitor and a second MOS capacitor are provided; the first MOS capacitor is used to offset the parasitic capacitance between the signal input end and the signal output end of the P-way filter unit; the second MOS capacitor is used to offset the parasitic capacitance between the signal input end and the signal output end of the N-way filter unit. The advantage is that the MOS capacitor is used as a feedback loop to offset the main zero point of the circuit, improve the out-of-band suppression of the filter, and increase the circuit stability; and the low-pass filter is supplemented with a reasonable optimization design, so that the working bandwidth of the low-pass filter can eventually reach 100MHz to 5.1GHz, with good out-of-band suppression and stable filtering effect.

The invention belongs to the technical field of static frequency converters, and provides a coupled harmonic current filtering method and system for an SFC rectifier, and the method comprises the steps: firstly carrying out the Fourier transform analysis of a current signal and a voltage signal, extracting a coupled harmonic current component in the current signal, and determining the frequency and amplitude of the coupled harmonic current; constructing a correction transfer function according to the extracted coupling harmonic current components; superposing the correction transfer function and a preset basic transfer function to obtain a total transfer function; and finally, according to the obtained total transfer function, changing the equivalent inductance and capacitance values of the filter circuit, and filtering the current of the static frequency converter rectifier. Coupling harmonic current parameters are accurately extracted through a harmonic analysis unit, a constructed correction transfer function can be matched with specific coupling harmonic current in a targeted mode, and the defects that an existing filter is high in universality and poor in pertinence are overcome. The influence of harmonic coupling current is considered, and the filtering effect is improved by correcting the transfer function of the existing filter.

The invention relates to a power grid harmonic detection and control method for a self-adaptive generalized integrator, and the method comprises the steps: improving the stable filtering capability and frequency selection capability of the generalized integrator under a frequency fluctuation condition through introducing an orthogonal feed-forward amplitude compensation branch; the filtering performance of the original generalized integrator on fifth and seventh harmonics is optimized, and the harmonic detection precision is improved; by adjusting the coefficient of the single-stage controller, no-static-error tracking can be carried out on any harmonic signal, and the universality of control under different harmonic working conditions is improved.