151 results about "Second order filter" patented technology

A second-order filter that blends accurate position information from a one source, and velocity information from another source, both suitably scaled, in a second-order complementary filter. The filter is arranged such that an internal integrator maintains a value that represents the difference in the rate of change of the accurate position information, and the velocity input of the other source. This velocity difference is applied to another integrator outside the filter, whose initial condition is the position error between the two sources to the second order filter. The output of this latter integrator is a correction signal that grows at a rate equal and opposite to the rate of error build-up of position data from the source whose velocity is used in the second order filter. This correction signal is summed with the original position signal. In addition, the output of the second order filter may be used as a highly accurate position signal.

The invention relates to a multichannel narrowband control algorithm for mechanical active vibration isolation. A vibration sensor picks, close to a vibration source, reference signals, narrowband band pass filters of all frequency ranges that are divided in advance extract time domain line spectrum reference signals, a multichannel second-order filter operation is utilized to obtain reference signals that are filtered by secondary channel inverse models and that are used for self-adoptive control, and the convergence speed which is faster than the speed obtained by an FxLMS algorithm can be obtained while the stability is ensured. A phase difference compensator which only contains second-order parameters and enables on-line self-adaptive adjustment of the parameters to realized along with frequency fluctuations is in series connection behind the narrowband band pass filters, so no phase difference exists between the extracted line spectrum reference signals and the original reference signals prior to extraction. In this way, the optimal solution fluctuation of a controller caused by line spectrum frequency fluctuations is inhibited, and the robustness of the control algorithm for frequency fluctuations is improved. Through the multichannel narrowband control algorithm, the convergence speed is fast, the great frequency fluctuation robustness is exhibited, and control effects are great in mechanical vibration amplitude and frequency fluctuation conditions.

The invention discloses a novel stop band gap ultra wide band antenna, wherein the antenna comprises a polygan gap antenna and a combined trap wave structure, namely, a combined trap wave is generated by opening a C-shaped gap on the T-shaped micro-strip feeder which serves as a feed unit and adding micro-strip wires in the polygan gap. The polygan gap antenna can generate ultra wide band characteristics and adopts a double frequency resonance oscillation trap wave structure similar to a second order filter to realize narrower stop band. Compared with the prior art, the stop band ultra wide band antenna can realize good filtering characteristics and has the advantages of small size and low cost.

The invention discloses an AC milliohm meter based on a complex programmable logic device (CPLD), and a measurement method therefor. The output of the CPLD is connected in series with a D/A converter and a second-order filter in turn and then forms a 1kHz voltage signal source; the voltage signal source is connected with a resistor to divide voltage; a feedback closed ring is connected in series between the voltage signal source and a tested resistor; the feedback closed ring consists of an error amplifier, a difference amplifier and a measurement range resistor and is connected with the CPLD; voltage at two ends of the tested resistor is connected with a band-pass amplifier through an isolating capacitor; the output of the band-pass amplifier is connected with a lock-in amplifier and a 20mV clamp control circuit respectively; the output of the 20mV clamp control circuit is connected with the CPLD and the resistor; the output of the lock-in amplifier is connected with an integral-type A/D converter; the lock-in amplifier and the integral-type A/D converter are connected with the CPLD respectively; and an MCU is connected between the CPLD and a display/separation module. The AC milliohm meter has test current less than 100 mA, has open circuit voltage within 20 mV, can test large-capacitance equivalent series resistance parameters, increases system integration level, and can improve the measurement resolution and signal-to-noise ratio of AC voltage.

The present invention discloses a power amplifier and a processing method thereof. The power amplifier comprises a second-order filter circuit, a modulation circuit and an output circuit; the output end of the second-order filter circuit is connected with the input end of the modulation circuit; the output end of the modulation circuit is connected with the input end of the output circuit; the output end of the output circuit is respectively connected with the input end of either filter circuit in the second-order filter circuit. In the processing method, the dual-feedback second-order filter circuit is applied; the signals are silenced by the second-order filter circuit, modulated by the modulation circuit, and then transmitted outwards by the output circuit. The adoption of the dual-feedback second-order filter circuit effectively reduces the harmonic distortion and noise, which are generated by the modulation circuit and the output circuit, improves the performance of the power amplifier, and reduces the costs of the power amplifier.

A power converter having a remote sensing system. The power converter includes a high-pass feedback signal, a remote sensing low-pass signal, a constant-sum filter combining the high-pass feedback signal and the remote sensing low-pass signal. The constant-sum filter is at least a second order filter and generates an error signal. The constant-sum filter is a three terminal low-pass filter and an input terminal, an output terminal, and a common terminal. The input terminal receives the remote sensing low-pass signal. The common terminal receives the high-pass feedback signal. The output terminal transmits the feedback control signal.

The invention discloses a signal filtering greenhouse temperature monitoring system based on Internet of Things technology, which is characterized in that it is mainly composed of a substation system and a master station system connected to the substation system through a wireless network; the substation system It consists of a substation microcontroller, a buzzer connected to the substation microcontroller, a first wireless transmission module, a signal processing unit, a refrigerator and an electric heater, and a temperature sensor connected to the signal processing unit; the master station The system is composed of the main station single-chip microcomputer, data storage and display which are respectively connected with the main station single-chip computer. The signal collected by the substation system of the present invention is sent to the main station system through the wireless network without connecting through lines, so that the whole monitoring system is simpler and the manufacturing cost is lower. The second-order filter circuit of the present invention can filter the interference signal generated during the wireless transmission of the signal, so as to prevent the interference signal from affecting the control accuracy of the present invention.

Provided is a loop filter which receives first and second currents whose current ratio is n (where n is a natural number). The loop filter includes a first-order filter path, a second-order filter path, and a third-order filter path. The first-order filter path includes an operational amplifier generating an output impedance by increasing by as much as n times an impedance of a second input node to which the second current is applied. The first-order filter path performs a first-order filtering on the first current applied to a first input node by using the operational amplifier. The second-order filter path performs a second-order filtering on the first current applied to the first input node. The third-order filter path performs a third-order filtering on the first current applied to the first input node.

The invention discloses a reactive power compensation and harmonic treatment system. The system comprises a reactive power compensation and harmonic treatment device which comprises voltage current transformers which are respectively connected to a power grid and are used for converting grid voltage into standard secondary voltage and secondary current to be used by an instrument control device, a second-order filtering loop which comprises a non-inductive resistor and a filtering reactor which are in parallel connection and is in series connection with the output end of the current transformer, a plurality of capacitor filtering branches which comprise a plurality of filtering capacitor groups, wherein one end of each of the filtering capacitor groups is connected with the second order filtering loop through the respectively corresponding breakers, and the other end of each of the filtering capacitor groups is connected with a power grid neutral point, and a detection control device which controls the switching of the connection and disconnection of the corresponding circuit breaker according to the collected power grid parameter values to control the number of the invested filtering capacitor groups. The system has the advantages of small floor space, filtering cutoff frequency does not change along with the change of a load, and harmonics are effectively eliminated.

The invention provides a BIT (Built-In Test) circuit of a multipath ground/open discrete magnitude input signal, which is mainly used for solving the problems of long test cycle, high measurement cost and poor reliability of test result in prior art. The BIT circuit of a multipath ground/open discrete magnitude input signal comprises at least two paths of serially connected second order filter circuits, a buffer circuit and a drive circuit, wherein one end of the second order filter circuit is a discrete magnitude input end while the other end thereof is a data output end, and the buffer circuit and the drive circuit are further connected with a decoding control circuit which is used for controlling data transmission and instruction decoding. The BIT circuit of a multipath ground/open discrete magnitude input signal only additionally adds two combined relays in hundreds of normal signal processing circuits, so that circuits are simple, practical and reliable, and the testability and the reliability of the circuits are improved greatly.

The invention discloses a high-power EMI (Electromagnetic Interference) filter. The high-power EMI filter comprises three phase current output load ends and three phase current input ends, wherein a differential mode inductor L1, a common mode inductor L2 and a common mode inductor L3 are connected between each of the three phase current output load ends and each of the three phase current input ends in series in sequence; the differential mode inductor L1 is connected with a differential mode capacitor C1X and a common mode capacitor C1Y to form a first-order filter; the common mode inductor L2 is connected with a differential mode capacitor C2X and a common mode capacitor C2Y to form a second-order filter; the common mode inductor L3 is connected with a differential mode capacitor C3X and a common mode capacitor C3Y to form a third-order filter; the differential mode capacitors C1X, C2X and C3X are bridged between a phase line and a neutral line; and the common mode capacitors C1Y, C2Y and C3Y are bridged between the neutral line and a ground line. According to the high-power EMI filter, the performance and safety of the filter under high current can be guaranteed, and EMC (Electromagnetic Compatibility) filtering in high-current and high-power systems can be met.

The invention discloses a small signal output circuit for an intelligent relay protection tester, which comprises a D/A conversion circuit, a second-order filter circuit, a voltage following circuit and an anti-surge circuit, wherein the D/A conversion circuit is connected with the second-order filter circuit; the output end of the second-order filter circuit is connected with the voltage following circuit; and the output end of the voltage following circuit is connected with the anti-surge circuit. According to the small signal output circuit for the intelligent relay protection tester provided by the invention, a PWM digital signal outputted by an external controller is converted into an analog signal via the D/A conversion circuit, signal output is then carried out via the second-order filter circuit, the voltage following circuit and the anti-surge circuit, and the circuit stability is good.

The invention discloses a desanding technology of an oilfield flown back fracturing fluid. The technology is designed to realize the closed continuous desanding, multilevel control and non-grounding desanding of the flown back fracturing fluid. A waste liquid is processed by a cyclone desanding device, the processed waste liquid enters a pressure relief degassing device for gas-liquid separation and filtering sedimentation, the obtained waste liquid is directly pumped into a filter-order filtering device through a first-order water pump, the filtered waste liquid is settled in a sewage pot, the settled filter waste is directly pumped into a second-order filtering device through a second-order water pump and is processed, and the finally obtained product is introduced into a purified water tank. The desanding technology has the advantages of reliable design, simple operation, no need of over-current, and substantial continuous desanding performance, and an apparatus for realizing the technology has the advantages of strong impact resistance, closed processing process, large processing capacity, and high desanding efficiency.

An angle-only tracking filter includes: a target angle discriminant unit configured to receive sensor signal outputs and form angle only observations of a target relative to an ownship; an ownship navigation filter configured to receive and filter ownship inertial navigation measurements; a model analyzer configured to receive and analyze the ownship inertial navigation measurements and select the order of target kinematics to be determined; and a target kinematics generator coupled to the angle discriminant unit, the navigation filter unit, and the model analyzation unit, including: a first-order filter unit configured to generate a target position from the target angle measurements and the ownship inertial navigation information; a second-order filter unit configured to generate a target velocity from the target angle measurements and the ownship inertial navigation information; and a third-order filter unit configured to generate a target acceleration from the target angle measurements and the ownship inertial navigation information.

The invention relates to a wind turbine generator tower frame vibration control method and a wind turbine generator tower frame vibration control system. The invention aims to solve the technical problems that the measurement is inaccurate and the vibration control effect of a tower frame is not good because of the vibration acceleration in a single direction of a cabin at the top of the existingmeasurement tower. According to the wind turbine generator tower frame vibration control method and system, the effects of measuring accurately and reducing the first order and/or second order inherent frequency amplitude of the cabin at the top of the tower in the direction of the resultant force thereof are achieved by performing vector resultant on the acceleration or the speed in any directionin a horizontal plane at the top of the tower, or measuring and calculating the vibration acceleration in the radius direction of a spherical surface which takes the intersection point of the horizontal plane at the top of the tower and the central axis of the tower frame as the centre of the sphere, performing first order and second order filtering on a resultant acceleration or resultant speedby utilizing a band pass filter to obtain a variable pitch control vibration input value for controlling the variable pitch rate based on the vibration acceleration of the top of the tower of a wind turbine, performing vector addition on the variable pitch control vibration input value and the variable pitch control vibration input value based on the rotating speed of a wind turbine generator, andfinally controlling the pitch rate of the wind turbine by utilizing the vibration input values of the two aspects above.

The invention discloses a signal mixed processing type greenhouse temperature monitoring system based on the Internet of Things technology, which is characterized in that it is mainly composed of a substation system and a master station system connected to the substation system through a wireless network; the substation The system consists of a substation microcontroller, a buzzer connected to the substation microcontroller, a cycle frequency stabilization module, a signal processing unit, a refrigerator and an electric heater, a temperature sensor connected to the signal processing unit, and a cycle frequency stabilization module The connected first wireless transmission module is formed; the substation single-chip microcomputer is also connected with the first wireless transmission module; Keyboard and second-order filter circuit and so on. The second-order filter circuit of the present invention can filter the interference signal generated during the wireless transmission of the signal, so as to prevent the interference signal from affecting the control accuracy of the present invention.

The present invention discloses a no-reference image objective quality evaluation method based on the structural distortion. The method comprises: obtaining first-order filtering images at eight different directions and without the direction of a distorted image to be estimated, and obtaining the maximum value images of the first-order filtering images; obtaining second-order filtering images at eight different directions and without the direction of the distorted image to be estimated, and obtaining the maximum value images of the second-order filtering images; obtaining the maximum value images of the first-order filtering images, the second-order filtering images at eight different directions and without the direction of the distorted image to be estimated and each local mode feature image of the maximum value image of the second-order filtering images to obtain each histogram statistic feature vectors; and testing all the histogram statistic feature vectors according to the support vector regression training models obtained according to the construction, and predicting and obtaining an objective quality evaluation value. The no-reference image objective quality evaluation method based on the structural distortion can effectively improve the correlation between the objective evaluation result and the subjective perception.

An equalization filter structure for filtering an audio signal within an audio system is disclosed. The equalization filter comprises a first and a second shelving filter each having a fixed first and a fixed second phase response, each of which is determined by a respective cut-off frequency and Q factor which represent the transfer characteristic of the corresponding shelving filter. The first and the second shelving filters are coupled in series and each shelving filter comprises at least one fourth order low-pass filter having a cut-off frequency, a Q factor and a first broadband gain and further at least one fourth order high-pass filter having a second broadband gain and the same cut-off frequency and the same Q factor as the low-pass filter. The fourth order low-pass filter and the fourth order high-pass filter are connected in parallel, such that both filters receive the same input signal and the corresponding filtered signals are summed to form a respective shelving filter output signal. Each fourth order low-pass and high-pass filter is composed of a cascade of two second order low-pass or high-pass filters, respectively, and each second order filter has the same cut-off frequency and Q factor as the corresponding shelving filter.

The invention provides a power amplifier capable of suppressing a pulling phenomenon. The power amplifier comprises a differential amplification tube composed of a transistor M1 and a transistor M2, a biasing tube composed of a transistor M3 and a transistor M4, second-order filter capacitors C1 and C2, and a differential magnetic field resonator, wherein the transistor M1 is connected with the transistor M3, and the transistor M2 is connected with the transistor M4; the control pole of the transistor M1 is earthed via the second-order filter capacitor C1 and serves as positive signal input of the power amplifier; the control pole of the transistor M2 is earthed via the second-order filter capacitor C2 and serves as the negative signal input of the power amplifier; the transistors M1 and M2 are connected with a power end via the differential magnetic field resonator; and the control poles of the transistors M3 and M4 are connected with the input of biasing voltage. According to the power amplifier provided by the invention, the differential magnetic field resonator and the even-order filter capacitors are used, so that second harmonic interference signals generated by the power amplifier can be greatly suppressed, and thus frequency pulling effect on a direct up-conversion transmitter is reduced.

The invention relates to an intrinsically safe explosionproof type intelligent temperature transmitting system. The system comprises a filtering and high-speed switching circuit, an MCU (Micro Control Unit), an AD (AC to DC) sampling and converting circuit, a DA (DC to AC) converting circuit, a photoelectric coupler and an isolation transformer, wherein the DA converting circuit comprises a PWM (Pulse-Width Modulation) transmission circuit, a second-order filtering circuit and a U/I conversion output circuit; the filtering and high-speed switching circuit, the AD sampling and converting circuit, the MCU, the photoelectric coupler, the PWM transmission circuit, the second-order filtering circuit and the U/I conversion output circuit are sequentially connected; and the AD sampling and converting circuit is integrated in the MCU. Compared with the prior art, the invention has the advantages of low power consumption, high integration level and the like.