21results 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 sliding mode-extended state observer vibration control method based on time delay compensation in the field of vibration control. The sliding mode-extended state observer vibration control method comprises the following steps: step 1) carrying out novel modeling on a four-side fixed support plate system; 2) designing an extended state observer; 3) designing a sliding mode controller; 4) designing a time delay compensator; and step 5) calculating the control quantity by using the NI-PCIe acquisition card and the Simulink. According to the invention, based on NI-PCIe hardware-in-the-loop platform development, the problems of system time lag, model uncertainty, influence of an inertial actuator and external excitation existing in a four-side fixed support plate are solved, and the total disturbance of the system including internal and external disturbance is estimated through an extended state observer. A content system is simplified into an integral series connection type for control by eliminating total disturbance through feedforward, and a delay compensator based on an enhanced differentiator is introduced to carry out non-delay design on the system, so that the vibration suppression performance of the sliding mode controller is improved.

The invention discloses a temperature compensation circuit, a power amplifier and a radio frequency front-end module, and the temperature compensation circuit comprises at least one first temperature compensation module, at least one second temperature compensation module, and an adjustment module which is connected with the first temperature compensation module and the second temperature compensation module. The adjusting module is connected with the power supply end of the power amplifier; the first temperature compensation module is used for outputting a first compensation signal to the compensation node in a first temperature interval, and the first compensation signal is in positive correlation with the temperature; the second temperature compensation module is used for outputting a second compensation signal to the compensation node in a third temperature interval, the second compensation signal is in positive correlation with the temperature, and the minimum value of the third temperature interval is larger than the maximum value of the first temperature interval; wherein the adjusting module is used for detecting the power supply voltage of the power amplifier in a first temperature interval and adjusting a first slope between the first compensation signal and the temperature according to the power supply voltage, and the power supply voltage is in positive correlation with the first slope.

The invention relates to a cavity length locking device and method of a low-cost optical resonant cavity based on a phase-locked loop. The device mainly comprises a reference laser frequency stabilization structure and a cavity length locking structure of the optical resonant cavity. The method comprises the following steps: locking the frequency of a reference laser at an atomic resonance point through a saturated absorption frequency stabilization method, coupling laser containing a modulation component into an optical resonant cavity, collecting a transmission spectrum, taking a phase-locked loop as a basis, and taking a modulation signal in a frequency stabilization loop of the laser as a reference; a demodulation signal with the same frequency and adjustable phase is obtained through phase locking and used for demodulating an error signal for locking the cavity length of the optical resonant cavity, and the cavity length of the optical resonant cavity can be locked through the error signal. According to the invention, an external optical modulation device is not needed, so that the cost is greatly reduced, the method is not limited by the modulation bandwidth, and an error signal with a relatively low frequency discrimination slope can be demodulated, thereby reducing the loop gain, enlarging the frequency discrimination range, and reducing the influence of a control system on the fineness of the optical resonant cavity.

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 discloses a power converter, which is a magnetic integrated current doubling rectifying circuit with a low transformer transformation ratio, and can not only improve the effective duty ratio of a system, but also reduce the gain of the circuit by adjusting the connection mode of a synchronous rectifying tube and a corresponding bridge arm. Therefore, the power converter can reduce the turn ratio of the transformer under the condition of the same output voltage, thereby reducing the loss of the transformer and reducing the cost of the transformer.

The invention discloses a pulse-modulated radio frequency power amplifier system and a magnetic resonance system. The amplifier system comprises a nonlinear correction unit, a radio frequency pre-amplification and driving amplification unit, a radio frequency power amplification unit, a directional coupler, a pulse synchronous switch unit and a filtering unit. Wherein the non-linear correction unit, the radio frequency pre-amplification and driving amplification unit, the radio frequency power amplification unit and the directional coupler form a closed loop, and the filtering unit is used for filtering signal components lower than a preset working frequency band in the formed closed loop, so that the gain of a low frequency band is reduced, the condition of self-excitation oscillation is destroyed, and the self-excitation performance of the antenna is improved. The self-excitation is avoided, the problem of potential instability of a low-frequency band in a radio frequency power amplifier system is solved, the whole system can work more stably and reliably, meanwhile, pulse modulation of sub-microsecond-level stable time can be achieved, and the problem is solved simply at low cost only by reasonably using the filtering function.

The application discloses a control method of structural vibration based on a controller saturation lower band active mass damper, and successfully reduces the vibration of a building structure by introducing an active mass damper and applying a control strategy. In order to meet the control input constraint and performance requirements, a state feedback optimal control law under the controller saturation is proposed by using a linear matrix inequality method; example analysis shows that the proposed control strategy can realize the stability of the closed-loop system and play the best performance, while reducing the control energy consumption and the floor level disturbance; compared with the case without considering the controller saturation, the proposed controller has smaller gain, reduces the energy consumption, and shows better anti-interference performance; numerical examples verify the effectiveness and feasibility of the proposed controller within the saturation limit; the application provides a new idea and method for solving the actual building structure control problem, and has important theoretical significance and practical application value.

The application belongs to the technical field of control, and particularly relates to a kind of water-soluble fertilizer production preparation self-adaptive control method and system, method includes: the state parameter in reactor is collected, and after normalization, constitute multidimensional state vector;Through Gaussian process regression, the nonlinear mapping between current state and control input and state change is established, and the trace of predictive covariance matrix is used to represent posterior uncertainty index;Establish a stochastic differential equation containing Brown motion and compound Poisson process as a state space model, associate volatility, jump intensity and posterior uncertainty index to represent unmodeled dynamic risk;For concentration, pH value and temperature constraints, construct a stochastic control barrier function, and derive high probability safety constraints based on Itô-Lévy formula;With the minimum control cost and index deviation as the goal, a convex optimization problem is constructed, and the control amount is solved online to regulate the feeding, stirring and temperature control equipment, so as to consider the control cost, index deviation and production safety.

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.

A signal adjustment method for a PPG apparatus and a PPG apparatus. The method comprises: when background light data does not meet a preset background light data range, or actual effective light data does not meet a preset first effective light data range, performing a dimming operation, the dimming operation comprising: determining an estimated current transfer ratio; estimating a driving current required by a light source and a gain required by an analog front end; calculating estimated effective light data of a PPG apparatus according to the estimated driving current required by the light source, the gain required by the analog front end, and the estimated current transfer ratio; when the estimated effective light data meets a preset second effective light data range, generating, according to the estimated driving current required by the light source and the gain required by the analog front end, a current / gain value to be adjusted. The signal adjustment method can enable a PPG signal to quickly and adaptively converge within a dynamic range of an ADC.

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 invention belongs to the technical field of radar imaging, and particularly relates to a near-field BP imaging method for gain compensation based on an antenna pattern. The method specifically comprises the following steps: step 1, measuring an actual directional diagram of an antenna under a darkroom condition; step 2, calculating a pixel value of any point in an imaging area based on a BP imaging method; step 3, calculating an angle between any pixel point in the imaging area and the transmitting-receiving antenna; step 4, according to the actually measured antenna pattern and the angle between the antenna and the pixel point, calculating the actual gain obtained by the radar echoes from different directions under each channel, namely the actual gain obtained by the transceiving antenna; and step 5, constructing a gain compensation matrix by using the actual gain obtained by each transmitting-receiving antenna, and compensating each pixel point of the imaging area by using the gain compensation matrix.

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 discloses a laser radar signal receiving method and a receiving circuit, the receiving circuit of a laser radar at least comprises a photoelectric element and a step-down circuit, when a voltage is applied to a first end of the photoelectric element, the photoelectric element generates a light current when receiving an echo signal, and the step-down circuit is connected with the first end of the photoelectric element. When a preset pulse is input to the step-down circuit, the step-down circuit is switched on, so that the first terminal voltage of the photoelectric element is reduced. The method comprises the following steps: when the laser radar emits pulse laser, inputting a preset pulse to the step-down circuit, so that the first end voltage of the photoelectric element is reduced and recovered after a preset time length, and the gain of the photoelectric element is reduced within the preset time length; the preset time length is matched with the delay time length of the echo signal reflected by the interior of the laser radar and received by the photoelectric element relative to the pulse laser. According to the invention, the influence of an echo signal, namely an internal interference signal, reflected by the interior of the laser radar can be reduced.

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.