92results about How to "Improve low frequency characteristics" patented technology

The present invention discloses a sine DC variable frequency one-driving-multiple air conditioner control system, comprising an outdoor unit controller, at least three indoor units and a DC variable frequency compressor, wherein, the outdoor unit controller further controls an outdoor unit intelligent control module, an intelligent frequency conversion module, an indoor-outdoor unit communication module and a temperature acquisition module; the outdoor unit intelligent control module is used for controlling the drive of the DC variable frequency compressor. The present invention also discloses a sine DC variable frequency one-driving-multiple air conditioner control method, which first calculates the needed frequency of the DC variable frequency compressor, and then calculates the instantaneous position and the velocity information of a DC variable frequency compressor rotor, and finally drives the DC variable frequency compressor. The present invention increases the service efficiency of the compressors of one-driving-multiple air conditioners, improves the high frequency characteristics and low frequency characteristics of air conditioners, and ensures that one-driving-multiple air conditioners save more energy.

The invention relates to a Rogowski coil-based integrator circuit for an electronic current transformer. The integrator circuit consists of a Rogowski coil, a low-frequency gain planarization analog integrator and a signal processing circuit, wherein the Rogowski coil is used for outputting a transient signal to the low-frequency gain planarization analog integrator and outputting a steady-state signal to the signal processing circuit; the low-frequency gain planarization analog integrator is used for processing the transient signal output by the Rogowski coil and is connected with the Rogowski coil and the signal processing circuit; and the signal processing circuit is used for processing an output signal of the low-frequency gain planarization analog integrator and performing digital integration on the steady-state signal output by the Rogowski coil, and then the processed signal is transmitted to a protecting channel and a metering channel through an output interface circuit. The integrator circuit has the advantages of measuring the steady-state signal with high precision, quickly responding to the transient signal, and providing measurement data of the protecting channel and the metering channel at the same time through one Rogowski coil, along with high temperature stability and vibration resistance.

The invention discloses an ultra-wideband planar phased array antenna and a beam scanning method thereof, and relates to the technical field of antennas. The ultra-wideband planar phased array antennacomprises a dielectric substrate, and a liquid crystal phase shifter network which is externally applied with a bias voltage and arranged on the dielectric substrate, wherein the liquid crystal phaseshifter network is composed of a plurality of liquid crystal phase shifter units. An antenna unit array which covers a plurality of frequency bands is arranged above the liquid crystal phase shifternetwork; and the antenna unit array is composed of a plurality of antenna units, wherein the antenna unit is a Vivaldi antenna with a slot line, and a liquid crystal phase shifter is powered through amicrostrip line-slot line structure. Compared with the prior art, the problems that the ultra-wideband phase-controlled profile is high in profile degree, large in antenna loss and low in utilizationrate are solved.

The invention discloses a combined coaxial full-frequency loudspeaker in a double-transduction mode, which includes a magnetic circuit structure, a voice coil is provided on the upper part of the magnetic circuit structure, and a vibration plate is provided at the output end of the voice coil, and the vibration plate is A disc made of piezoelectric material is used, and the disc is fixed on the magnetic circuit structure through a ring and a washer. The present invention combines the dynamic speaker and the piezoelectric speaker, and uses the transducer device of the piezoelectric speaker - the piezoelectric disc as the vibrating plate (cone) of the dynamic speaker to work in the low frequency band as an electrodynamic transducer. Working with piezoelectric transducers in the high-frequency band, a new type of unique combined full-range speaker is formed. Full frequency band work. The invention can be widely used in the field of loudspeakers.

A sacrifice layer 36 is exposed through a chemical charging port 31 so that the sacrifice layer 36 and sacrifice layer 35 are etched and removed by an etchant introduced from the chemical charging port 31. Since the surface of an Si substrate 22 is exposed to an etching window 34 corresponding to the removed portion of the sacrifice layer 35, the Si substrate 22 is crystal anisotropically etched below the etching window 34 to form a cavity 23. In contrast, in a space corresponding to the etched and removed portion of the sacrifice layer 36, since the surface of the Si substrate 22 is covered with a protective film 32, the Si substrate 22 is not etched to form a bent hole 26 therein. The cavity can be formed in the semiconductor substrate by an etching process from the surface side. Moreover, a bent hole having a great acoustic resistance can be easily formed.

The invention relates to a servo acceleration meter based on differential infrared displacement sensing. The differential infrared displacement sensing servo acceleration meter is characterized in that: a shell is made of a soft magnetic material; a cylindrical detection quality block is sleeved outside a cylindrical permanent magnet; the cylindrical detection quality block is fixed on the shell by a spring; a plurality of magnetic driving coils are wound outside the cylindrical detection quality block; two ends of each magnetic driving coil are connected with a feedback current input port which is formed on the shell; a light blocking sheet is fixed on the cylindrical detection quality block; a light transmission hole is formed on the light blocking sheet; two sheet-like infrared receiving tubes are arranged on a supporting plate in parallel from up to down; the supporting plate is fixed on the shell; infrared transmitting tubes are arranged on the shell; the light transmission hole on the light blocking sheet is positioned between the infrared transmitting tubes and the infrared receiving tubes; and output terminals of the infrared receiving tubes are connected with an infrared displacement sensing signal output port through signal lines. The servo acceleration meter based on the differential infrared displacement sensing is characterized by simple structure, good low-frequency property, high measurement accuracy and high sensitivity.

This invention relates to a torque control device and a method for DC frequency conversion compressors including a current sampling part and a control part, in which, an 180deg. sine wave DC conversion mode is applied to test the position of a compressor rotor timely and control is carried out by the applied drive voltage to the motor of the drive compressor so as to adjust the output torque of the compressor timely and the compressor can keep torque balance at any time in the process of operation.

A wide frequency band charge amplifier is used to change charge voltage, which is characterized in that a feedback resistance which is jumped between a negative input end and output end of an operational amplifier to a R11, R12 series circuits in the widely-known charge amplifier circuit, a reference end G is connected to a feedback by-passing branch through a connecting point of the R12, the feedback by-passing branch is formed through connecting R3 and C2 in series, when R11=R12=R, the feedback by-passing branch which is connected can lead a breaking frequency f0 of a charge amplifier output end VO without the feedback by-passing branch to reduce to f1=f0/X, a proposed design formula of the technical principle that resistance with low electrical resistance value is used to design even low frequency charge amplifier is: R3 = 0.5R*20.5, C2 = 2XRC1/R3, therefore, low-frequency characteristic of the widely-known charge amplifier which is only applied to medium high frequency is optimized, and wide frequency band charge amplifier is realized.

The invention provides a self-adaption Q-value loudspeaker comprising a support, an electromagnetic assembly, a voice coil, and a diaphragm. The electromagnetic assembly is supported by the support, and the voice coil is disposed on the magnetic gap of the electromagnetic assembly, and can vibrate freely. The outer periphery of the diaphragm is connected with the support by an edge, and the inner periphery is connected with the above mentioned voice coil. The edge is the pipeline edge, which is provided with a plurality of air exhaust holes. The self-adaption Q-value loudspeaker is advantageous in that the production technology is simple, and the cost is low; the problems of the conventional loudspeaker such as distortion and turbid unclear low frequency caused by the easy deformation of the edge in the large dynamic state can be solved; during the vibration of the diaphragm, the axial motion of the pipeline edge can be driven, and the edge can be compressed, and then the air quantity of the pipeline edge can be adjusted automatically, and the self-adaption change of the Q-value of the loudspeaker can be carried out, and therefore the transient response and the low frequency characteristic of the loudspeaker can be improved, and the high technical value and the high economic value can be provided.

The invention discloses a piezoelectricity ceramic piece and a piezoelectricity ceramic loudspeaker adopting the same. The piezoelectricity ceramic piece takes the shape of a butterfly, that is, two ends of the piezoelectricity ceramic piece are broad, and the middle of the piezoelectricity ceramic piece shrinks inwards; the piezoelectricity ceramic loudspeaker comprises a front cover with sound holes formed in the middle, a vibration sound production component formed by an elastic vibrating diaphragm or an organic vibrating diaphragm, a metal diaphragm frame or a metal vibrating diaphragm, a piezoelectricity ceramic piece or the like is fixedly arranged in the front cover; a rear cover is fixedly connected with the front cover; the extraction electrode of the piezoelectricity ceramic piece is led out of the rear cover by a flexible printed circuit board to serve as the electric signal end of the piezoelectricity ceramic loudspeaker. The invention has the advantages that the low-frequency characteristic and the intermediate frequency tone of the butterfly-shaped piezoelectricity ceramic piece are good; and besides, the low-frequency characteristic of the piezoelectricity ceramic loudspeaker adopting the butterfly-shaped piezoelectricity ceramic piece, an obvious mid-frequency valley does not exist, the sound quality of a mid-frequency belt is good, and the distortion is less.

The invention relates to a high-dynamic charge type piezoelectric ceramic drive power supply. The signal output end of a control module is connected with the forward end of a power amplifier, the signal output end of the power amplifier is connected with a piezoelectric ceramic element, and the piezoelectric ceramic element is connected with a precise capacitor. The high-dynamic charge type piezoelectric ceramic drive power supply is characterized in that one end of the precise capacitor and one end of the piezoelectric ceramic element are respectively connected with the input end of an error integral operational amplifier, and the output end of the error integral operational amplifier is connected with the negative end of the power amplifier.

The invention provides a passive servo earthquake rotation speedometer and belongs to the field of earthquake measurement devices. The passive servo earthquake rotation speedometer comprises a bottom plate, a spoke type mass spring device, two pendulum type passive servo large damping moving coil transducers and a circuit board; each pendulum type passive servo large damping moving coil transducer is composed of a swing frame, a moving coil component and a magnetic circuit system; one ends of the two swing frames are symmetrically installed on the two sides of a mass ring of the spoke type mass spring device; each moving coil component is installed at the other end of the corresponding swing frame and extends into a magnetic gap of the corresponding magnetic circuit system; the circuit board is composed of two passive servo large damping moving coil transduction circuits, two angular acceleration conditioning circuits and a synthesis circuit; the transducers are connected with the input ends of the corresponding transduction circuits; the output ends of the transduction circuits are electrically connected with the input ends of the corresponding angular acceleration conditioning circuits; the output ends of the two angular acceleration conditioning circuits are connected with the synthesis circuit separately; and the synthesis circuit is used for eliminating a non rotational component, synthesizing a rotational component and outputting a voltage signal which is proportional to an earthquake rotation acceleration.

The invention discloses an active and semi-passive composite vibration isolator, and relates to the technical field of vibration isolation mechanisms. A magnetostriction unit and a magneto-rheological elastomer unit are arranged in a composite vibration isolator frame. The magnetostriction unit is arranged below the magneto-rheological elastomer unit. The magnetostriction unit and the magneto-rheological elastomer unit are connected in series. The composite vibration isolator is jointly composed of the magnetostriction unit, the magneto-rheological elastomer unit and the composite vibration isolator frame. According to the active and semi-passive composite vibration isolator, an upper magnet exciting coil magnetic field acts on a magneto-rheological elastomer, the elasticity modulus of the magneto-rheological elastomer is adjusted, and the composite vibration isolator conducts semi-passive control over vibration transmission between equipment and a base body during high-frequency small amplitude acting; and a lower magnet exciting coil and a permanent magnet magnetic field act on a magnetostriction bar, the expansion and contraction quantity of the magnetostriction bar is adjusted, the composite vibration isolator conducts active control over vibration transmission between the equipment and the base body during medium-low-frequency large amplitude acting, and active and semi-passive composite control vibration isolation within the full-band range is overall achieved.

The invention discloses an earphone capable of enhancing a low-frequency characteristic. The earphone comprises an earphone plug, in-ear sound-generating parts and an earphone cable connecting the earphone plug and the in-ear sound generating parts. Each in-ear sound-generating part comprises a shell, a loudspeaker single-body, an earphone rear cavity and an extension tube which is communicated with the rear cavity and accommodates the earphone cable. The earphone cable is fixed in the extension tube via a fixing component. The extension tube is internally provided with a low-frequency enhanced sound-guiding tube which is consistent with the extension direction of the extension tube. The rear cavity and the external space of the earphone are communicated via the sound-guiding tube. The earphone cable is provided with zipper teeth which are provided with a zipper head which can be matched with the zipper teeth in use. The zipper teeth are engaged with each other or separated via the zipper head. The low-frequency characteristic of the earphone is enhanced via changing the cavity structure of the earphone so that low-frequency performance of the earphone is obviously enhanced, the low-frequency sound effect of the earphone is enhanced, a phenomenon of winding of the earphone cable is also effectively avoided and thus the service life of the earphone is guaranteed.

The invention discloses a broadband ridge waveguide power synthesizer based on a gradient ridge and a power synthesizer device. The synthesizer has a compact structure, large bandwidth, low insertionloss and high bearing power and can realize higher power synthesis output. The broadband waveguide power synthesizer comprises a ridge waveguide which is composed of an upper cavity, a ridge cavity and a lower cavity, a first port which is arranged at one end of the ridge waveguide, a second port which is arranged at the other end of the ridge waveguide, a third port which is arranged at the frontend of the ridge waveguide and the gradient ridge, an penetrating ridge and a chamfered ridge which are arranged in the ridge cavity.

The invention discloses a method for improving giant magneto-impedance effect of composite materials, wherein the composite materials are formed by electric conduction metal, and the surface of the electric conduction metal is adhered with a soft magnetism thin film. According to the method, pulling stress is exerted on metal wires. Though the method is simple, giant impedance characteristics of silk-shaped composite materials can be improved notably. Low frequency characteristics of a composite structure are more notable with the increase of the exerted pulling stress, and change rate of giant magneto-impedance rate is larger. According to test results, impedance can be changed when small pulling stress is exerted to receiving materials. When loading of the pulling stress is dismounted, the materials can still keep the giant magneto-impedance rate changing effect generated through the pulling stress.

The invention provides a passive servo large-damping earthquake rotation accelerometer, and belongs to the field of earthquake measurement devices. The passive servo large-damping earthquake rotation accelerometer comprises a bottom plate, a spoke-type mass spring device, two swing-type passive servo large-damping moving coil transducers and a circuit board. Each swing-type passive servo large-damping moving coil transducer comprises a swing frame, a moving coil assembly and a magnetic circuit system. One ends of the two swing frames are symmetrically installed on the two sides of a mass ring of the spoke-type mass spring device, and the moving coil assemblies are installed at the other ends of the swing frames and stretch into magnetic gaps of the magnetic circuit systems. The circuit board comprises two passive servo large-damping moving coil transduction circuits, two angular acceleration conditioning circuits and a combination circuit. The transducers are connected with the input ends of the transduction circuits, the output ends of the transduction circuits are electrically connected with the input ends of the angular acceleration conditioning circuits, and the output ends of the two angular acceleration conditioning circuits are connected with the combination circuit. The combination circuit is used for eliminating non-rotation components, combining rotation components and outputting voltage signals in direct proportion to the earthquake rotation acceleration.

The invention provides a loudspeaker. The loudspeaker comprises a basin rack, a magnetic circuit system, a voice coil, a voice basin, a wave damper and a telescopic tube, wherein the magnetic circuit system is mounted on the basin rack, the voice coil is mounted in a magnetic field of the magnetic circuit system, the voice basin is connected with the voice coil, the wave damper is used for fixedly connecting the voice coil and the voice basin, and the telescopic tube is arranged on the back face of the voice basin; one end of the telescopic tube is connected with the voice basin, and the other end of the telescopic tube is connected with the basin rack. According to the loudspeaker provided by the invention, the telescopic tube is arranged at the edge of the voice basin and has good telescoping performance, so that the voice basin can keep good linear operating characteristics during large dynamic operation; the telescopic tube is arranged on the back face of the voice basin, so that the vibration area of the voice basin is not occupied, the low-frequency characteristics of the loudspeaker are improved greatly, and the loudspeaker can have the working performance of high efficiency and high fidelity.

The invention discloses a multi-mode resonance-based ultra-wideband band-pass filter, which comprises an open-circuit stub structure (1), microstrip feeder structures (2) and (3) and a ground surface (5) of the lower surface of a dielectric plate. The ultra-wideband is achieved by an interdigital coupling structure formed by transmission microstrip lines in the open-circuit stub structure and the microstrip feeder structures. The related filter has small return loss and insertion loss, good low-frequency characteristic and harmonics inhibition property. The filter is simple in design, compact in structure, attractive in appearance, convenient to process and low in cost, and can achieve 3.1-10.6GHz ultra-wideband.