11results about How to "Reduce gain" patented technology

An electric power assisted steering assembly comprises a steering mechanism which operatively connects a steering wheel to the roadwheels of a vehicle, a torque sensing means adapted to produce a first output signal indicative of the torque carried by a portion of the steering mechanism, a means for producing a second output signal indicative from a signal indicative of the angular velocity of the portion of the steering mechanism, an electric motor operatively connected to the steering mechanism, a signal processing unit adapted to receive the two output signals and to produce therefrom an overall torque demand signal representative of a torque to be applied to the steering mechanism by the motor, and a motor drive stage adapted to provide a drive current to the motor responsive to the torque demand signal. The overall torque demand signal includes a damping component that is dependent upon the second output signal. The means for producing the yaw damping component includes a filter having one pole and one zero, and in use the second signal is passed through the filter to produce the damping component, the frequency of the pole and zero being selected such that the filter provides a band between the pole and zero within which the phase of the filtered second signal and the velocity signal are further out of phase or in phase than within the band.

The invention discloses a quasi-single-mode circular waveguide conical horn antenna, a radar and a communication device. The quasi-single-mode circular waveguide conical horn antenna comprises a circular waveguide section and a conical horn section. Conductor loss is reduced by remarkably increasing the diameter of the circular waveguide, and axial periodic annular grooves are formed in the inner wall of the circular waveguide to form a spatial mode filter and a selective attenuation high-order mode, so that high radiation efficiency and high mode purity are realized at the same time in a millimeter wave frequency band. And the conical horn section adopts an index profile to realize high-directionality radiation. The antenna structure effectively solves the technical problems of large loss and impure mode in a millimeter wave high-frequency band in the traditional design.

The invention provides a broadband gain positive slope amplitude-phase control multifunctional chip for a T / R assembly, which relates to the technical field of radio frequency integrated circuits and comprises a receiving channel, a transmitting channel, an equalization circuit, a numerical control attenuator, a numerical control phase shifter, a transmitting-receiving change-over switch module and a parallel control module. The parallel control module is used for outputting parallel control signals to the numerical control attenuator, the numerical control phase shifter and the transceiving change-over switch module; the equalization circuit is respectively connected with the receiving channel and the transmitting channel through the transmitting-receiving change-over switch module, so that a signal path of the receiving channel and a signal path of the transmitting channel multiplex the equalization circuit, the numerical control attenuator and the numerical control phase shifter; and the equalization circuit is of an on-chip integrated structure and is used for adjusting the gain of the receiving channel and the gain of the transmitting channel to present a positive slope characteristic relative to the frequency in a wide frequency band so as to compensate the frequency attenuation of an external device.

The invention discloses a starting circuit for suppressing starting overshoot, which is integrated in a DCDC converter and does not need an external expansion special device. The circuit comprises a reference voltage module, a step voltage slow rising module, a timer and an operational amplifier self-bias module. The step voltage slow rising module generates a soft start voltage signal VSTART to a first positive input end of the operational amplifier self-bias module, the reference voltage module outputs a reference voltage VREF to a second positive input end of the operational amplifier self-bias module, and a negative input end of the operational amplifier self-bias module inputs a feedback voltage VFB; the timer outputs a starting enable signal of the operational amplifier self-bias module; the soft start voltage signal VSTART generated by the step voltage slow-rise module realizes that the output voltage in the starting stage of the DCDC converter slowly rises from 0 to a rated value, and starting surge current and voltage overshoot are effectively inhibited.

The invention provides an indoor ultra-wideband transparent directional antenna, which comprises a transparent outer cover, a transparent bottom plate, a base, a first rhombus array and a second rhombus array, and is characterized in that each of the first rhombus array and the second rhombus array comprises four transparent oscillators, and the four transparent oscillators are arranged in a rhombus shape; the first rhombus array is connected with the first feed network, and the second rhombus array is connected with the second feed network. The diamond array can maximize the diagonal distance between the units, which is crucial for suppressing the grating lobes of the antenna, especially for suppressing the grating lobes at the high-frequency end. And the grating lobes can cause energy to radiate towards unwanted directions, so that the gain and efficiency of the antenna are reduced. The four transparent oscillator diamond arrays achieve good balance among performance, flexibility, complexity and cost.

This application discloses a crystal oscillator control device, comprising: a differential amplifier, with a first input voltage of a reference voltage, a second input connected to a first terminal of the crystal oscillator, and an output connected to a second terminal of the crystal oscillator; an input of a self-biasing control module connected to the output of the crystal oscillator; and an output of the self-biasing control module connected to the bias terminal of the differential amplifier. When the crystal oscillator is in the oscillation state, the voltage amplitude at the output of the differential amplifier increases from a first voltage value to a second voltage value, the bias current provided by the self-biasing control module decreases from a first current value to a second current value, and the gain of the differential amplifier is greater than a preset gain. When the crystal oscillator is in the resonance state, the voltage amplitude at the output of the differential amplifier remains at the second voltage value, the bias current remains at the second current value, and the gain of the differential amplifier decreases to the preset gain value. This solution achieves rapid crystal oscillation start-up and reduces power consumption during operation.

The application relates to a high-power-supply-rejection low-voltage-difference linear voltage stabilizer based on gate capacitance offset, which comprises an error amplifier, a power tube M P , a feedback network R1 and R2, a load capacitor C L , a frequency compensation capacitor C M and a gate capacitor offset circuit; the output end of the error amplifier, the output end of the gate capacitor offset circuit, the gate of the power tube M P and one end of the frequency compensation capacitor C M are connected; the other end of the frequency compensation capacitor C M , the drain of the power tube M P , one end of the resistor R1, one end of the load capacitor C L and the V OUT end are connected; the source of the power tube M P is connected to the V IN end; the other end of the load capacitor C L , one end of the resistor R2 and the ground end GND are connected; the other end of the resistor R1, the other end of the resistor R2 and the non-inverting input end V FB of the error amplifier are connected. The application changes the equivalent capacitance of a node by introducing a gate capacitor offset circuit at the output end of the error amplifier, reduces the input-to-output gain and improves the power supply rejection capability.

The application relates to a comprehensive benefit-based optical remote sensing satellite imaging parameter optimization method, and belongs to the technical field of remote sensing satellite imaging effect improvement and optimization. The method solves the problem of unclear image quality in the prior art. Specifically, the method comprises the following steps: obtaining an initial image of a remote sensing satellite, obtaining imaging conditions of the initial image, and setting initial imaging parameters before initial image imaging; the parameters include integral order M and gain G; determining the imaging parameters to be optimized in the initial parameters based on the number of saturation points, the average gray value and the dynamic range of the initial image; obtaining first imaging parameters based on the live imaging conditions of the initial image according to an imaging parameter mapping table; obtaining second imaging parameters according to the initial image quality; and calculating the parameter values of the initial imaging parameters to be optimized based on the first and second imaging parameters. The purpose of improving the image quality is achieved.

The application discloses a kind of ultra-wideband low profile composite structure monopole antenna, including antenna radiator, metal short-circuit column, lumped loading module, metal floor and coaxial connector;The center position of the metal floor is provided with coaxial connector;Coaxial connector is connected with the bottom of antenna radiator;The antenna radiator is located above the center of metal floor and there is a certain spacing between the bottom and the metal floor, metal short-circuit column is set at equal intervals around the antenna radiator, and the bottom of metal short-circuit column is installed on the lumped loading module, and the lumped loading module is located on the metal floor.The application has the characteristics of ultra-wideband, low profile and omnidirectional radiation.

The application discloses a multi-service common-aperture series-fed filter antenna and a design method thereof. The antenna comprises an antenna body, N independent input ports are arranged on the antenna body, and each input port supports one working frequency band. The N input ports are arranged on different radiators for multi-frequency feeding, and a filter structure is arranged on each radiator to realize high isolation between the ports. Radio frequency signals of each working frequency band are input through the corresponding input ports and radiated to the free space by the same antenna body to realize multi-service common-aperture and common-antenna-body. The number of antennas required by a radio frequency communication device formed by the antenna and the space occupied by the antennas can be reduced to 1 / N of the split design. High-impedance feed lines and radiators are alternately connected to feed each radiator in phase as much as possible to realize the electrical characteristics of high gain and horizontal omnidirectional radiation.

The invention is suitable for the technical field of radio frequency, and particularly relates to a power amplifier and a radio frequency chip. The power amplifier comprises an out-of-band gain suppression circuit, a first-stage bias circuit, a first amplification circuit, an inter-stage matching circuit, a second-stage bias circuit, a second amplification circuit, a harmonic suppression circuit and an output matching circuit. The input end of the out-of-band gain suppression circuit is used as the input end of the power amplifier; the out-of-band gain suppression circuit is used for receiving the radio frequency signal and suppressing the out-of-band signal from being input to the first amplification circuit; the harmonic suppression circuit is used for suppressing a harmonic component in the radio frequency signal output by the second amplification circuit; compared with the prior art, the power amplifier provided by the invention can realize out-of-band gain suppression and harmonic suppression, can quickly adjust the gain according to the output power of the power amplifier, optimizes indexes such as out-of-band noise and harmonic components, greatly reduces interference to other frequency bands, and improves the performance of the power amplifier.