40results about How to "Reject common mode signals" patented technology

The invention discloses a sampling holding circuit applied to a high-speed high-precision circuit. The sampling holding circuit comprises a full-differential type operational amplifier, two sampling capacitors Cs, two sampling switches S1 and five selective switches and a low-pass filter circuit formed by a resistor R1 and a capacitor C1. The full-differential type operational amplifier is a gain enhancement folding cascade full-differential type operational amplifier, a sampling switch S1 is a grid voltage bootstrap switch, connected structures of the positive end and the negative end of the full-differential type operational amplifier are completely same, and a signal input end passes through the low-pass filter circuit to be connected with a lower pole plate of the sampling capacitors Cs through the sampling switches S1. A selective switch S3 is connected with the lower pole plate of the sampling capacitors Cs and the output end of the full-differential type operational amplifier. An upper pole plate of the sampling capacitors Cs is connected with the input end of the full-differential type operational amplifier, a selective switch S4 is connected with upper pole plates of the two sampling capacitors Cs, and a selective switch S2 is connected with the input end and the output end of the full-differential type operational amplifier. The sampling holding circuit can achieve sampling holding of the input signals in the high-speed high-precision circuit.

The invention discloses a single-converted-to-double low noise amplifier with a highly balanced and stabilized differential output gain phase. The amplifier comprises a common source or common emitter input amplifying transistor pair which comprises a first transistor and a fourth transistor, a common gate or common base amplifying transistor pair which comprises a second transistor and a third transistor, a tail current source pipe and output load circuits with tight coupling differential inductors; a fourth inductor L4 and a fifth inductor L5 are tight coupling differential inductors; C1 and C2 are differential capacitors with the same capacitance values; L0 and L1 also are tight coupling differential inductors. For the amplifier disclosed by the invention, since output loads adopt the tight coupling differential inductors L4 and L5 and the differential capacitors C1 and C2 for resonance, the balance and the stability of the differential output gain phase are improved, and the high-impedance tail current source pipe M5 can well restrain a common mode signal. The amplifier disclosed by the invention has excellent robustness when the PVT (Pressure Volume Temperature) and a working frequency point are changed, and at the same time, the amplifier has an excellent anti-interference capacity for the medium base noise.

A universal pulse width modulation method for a multi-level inverter includes the following steps: a, carrying out per unit of reference input voltages; b, calculating a two-level space vector pulse width modulation duty ratio; c, calculating in which layer a reference voltage vector is on; d, performing vector reverse mapping; e, inhibiting common-mode voltages; and f, generating pulse-width modulated waves. A voltage vector switching time duty ratio of an inverter is calculated by a simple two-level space voltage vector modulation algorithm, then vector compression is performed on the duty ratio, a mapping relation based on the voltage vector and level is established, and multi-level voltage conversion can be effectively achieved through the series of conversion. Through level conversion, the voltage vector that has a common-mode voltage inhibition capability can be output easily and quickly, and a specific pulse width modulation output state is selected to prevent generation of common-mode voltages, thereby effectively inhibiting common-mode components included in output voltages of a multi-level inverter.

The invention discloses a data through-the-earth transmission method based on sound waves, and belongs to the technical field of through-the-earth communication. The data through-the-earth transmission method is characterized in that low-frequency sine waves are taken as an information carrier, after data to be transmitted are processed such as being amplified and modulated through information transmitting equipment, sound wave signals are generated from sound generation equipment and are coupled to the earth, and then transmission of data is completed; after information is transmitted to a receiving end, a sound wave sensor senses the sound wave signals and the sound wave signals are converted into electric signals, the electric signals are processed such as being amplified, filtered and demodulated by information processing equipment at the receiving end, and information transmitted from a transmitting end is recovered. According to the method, due to adoption of a pulse width modulation and demodulation technique, the data transmission reliability is improved, and with the combination of hardware filtering and software filtering, a low bit error rate of information is ensured, the method can be effectively applied to ground-to-underground information issuing and rescue and relief work in hazard in underground working environments such as coal mines.

The present invention discloses one kind of single phase AC input electromagnetic interference inhibitor circuit, and relates to single phase input EMC circuit. The circuit consists of common-mode inductor including three windings and four capacitors connected together. The present invention can inhibit high frequency harmonic waves and reach corresponding EMC standard.

The invention discloses an ultraviolet light communication system based on a SR digital signal processing technology. A signal processing module is developed, wherein a high speed floating point type DSP chip is taken as a core and a FPGA is a coprocessor. A DSP main processor mainly carries out modulation and demodulation on a signal. The FPGA coprocessor is responsible for digital filtering and data buffering after the data is collected. The system comprises an ultraviolet light transmitting antenna, an ultraviolet light source driving module, a signal processing module, an upper computer and an ultraviolet receiving antenna. The signal processing module is communicated with the upper computer through a serial port. The ultraviolet receiving antenna receives an ultraviolet light signal. The module converts the light signal into a voltage signal and transmits to the signal processing module. The ultraviolet light source driving module receives a control signal of a signal processing unit and drives the ultraviolet receiving antenna to emit an ultraviolet signal. The design in the invention satisfies requirements of industrialization, a practical ability and miniaturization. High-efficient transmission of a long distance and a large amount of data can be realized.

The invention discloses an open circuit stub loaded coupled line feed-based balance dual-passband filter. The balance dual-passband filter comprises a metal circuit; and the metal circuit comprises acoupled feed network and a resonator. By adopting an open circuit stub loaded type couple feed structure, common-mode signal suppression within a full-frequency range can be realized; and meanwhile, the adopted resonator has two controllable difference module resonant modes, so that dual-frequency difference module band-pass operation can be realized.

The invention discloses an LTCC balanced band-pass filter based on multi-frequency coupling, comprising two half-wavelength resonators and two groups of feeders. The two half-wavelength resonators are each composed of micro-strip lines in three different conductor layers, and the micro-strip lines in different conductor layers are connected by metal through holes. First coupling regions (211) of the two half-wavelength resonators are coupled to each other in the form of parallel coupling. The two groups of feeders (501, 502, 503) are disposed in the same conductor layer, and feed second coupling regions (411) of the two half-wavelength resonators under the feeders in the form of vertical coupling. The size of the filter is reduced effectively. The filter has high common-mode rejection ratio. Source-load coupling is introduced between the feeders, three transmission zeros are produced, and the selectivity of pass band is improved.

The invention discloses a symmetric integrated stacked transformer. The symmetric integrated stacked transformer comprises a substrate, a first layer of medium, a second layer of medium and a third layer of medium, which are arranged on the substrate from bottom to top in sequence, a latticed shield grid, which is positioned in the first layer of medium, a primary coil, which is positioned in the second layer of medium, and a secondary coil, which is positioned in the third layer of medium, wherein the shield grid is arranged on the lower plane of the first layer of medium; the primary coil is formed by parallel connection of two circles of square micro-strip coils, which are separated with each other and are symmetrical around the axis, and is arranged on the lower plane of the second layer of medium; the secondary coil is formed by series connection of fives circles of square micro-strip coils, which are separated with each other and are symmetrical around the axis, and is arranged on the lower plane of the third layer of medium; the adjacent coils in pairs are crossly connected with each other at the places close to the axis through two connecting lines, one remaining circle of the coil is directly connected at the place close to the axis through the connecting line of the same metal layer, and a center tap of the secondary coil is arranged on the middle point of the coil. The symmetric integrated stacked transformer has the characteristics of good symmetry, high rate of turn and high magnetic induction coefficient.

The invention discloses a balance type common-mode filter with adjustable broad band. The filter comprises a dielectric substrate, a first metal layer and a second metal layer, wherein the first metal layer is arranged on one surface of the dielectric substrate; a pair of differential microstrip transmission lines are arranged on the first metal layer; the second metal layer is arranged on the other surface of the dielectric substrate; the second metal layer is used as a grounding metal surface, and at least one groove line annular resonator is arranged on the second metal layer; each groove line annular resonator is formed by four groove lines in a surrounding manner, wherein the four groove lines are arranged on the second metal layer, connected in sequence, and distributed along the rectangular four sides; the differential microstrip transmission lines are in axial symmetry relative to a first straight line; the projections of the groove line annular resonators on the second metal layer are all in axial symmetry relative to the first straight line; and a variable capacitor is arranged between one group of opposite groove lines, parallel to the first straight line, of the groove line annular resonators separately. By implementation of the technical scheme of the filter, the common-mode stop band frequency of the balance type adjustable common-mode filter can be adjustable in a bidirectional way by controlling the capacitance values of the two viable capacitors loaded on the groove line annular resonators respectively so as to restrain the target common-mode signal.

The invention provides a BFSK modulation circuit which comprises a first oscillating circuit, a second oscillating circuit and a comparison circuit. The first oscillating circuit and the second oscillating circuit are both connected with an input signal, the two circuits are in intermittent oscillation at the same time, and the input signal is converted into different voltage values; lastly, the frequency of the input signal is determined through a comparator, and namely the frequency of the input signal is '1' or '0'. By the adoption of the BFSK modulation circuit, a noise signal mixed with the input signal is a common-mode signal, the common-mode signal can be suppressed in a differential form, and therefore a comparison result is more accurate.

The invention relates to an electret microphone picking up differential signals. The electret microphone comprises a shell. The bottom of the shell is provided with sound holes. The top of the shell is provided with a circuit board. An electrode plate is arranged above the sound holes and in the shell. A second insulation gasket is arranged on the electrode plate. A vibration membrane is arranged on the second insulation gasket. A first insulation gasket is arranged on the vibration membrane. A back electrode plate is arranged on the first insulation gasket. The back electrode plate, the vibration membrane and the electrode plate are respectively and electrically connected with the circuit board. The back electrode plate and the vibration membrane form a capacitor. The vibration membrane and the electrode plate form another capacitor. The vibration membrane is connected with the ground. The back electrode plate is connected with an inverted input end of an operational amplifier. The electrode plate is connected with an in-phase input end of the operational amplifier. A differential structure is formed among the back electrode plate, the electrode plate and the vibration membrane, and therefore the electret microphone in differential structure is formed. The electret microphone can effectively amplify different-mode signals and restrain common-mode signals, thereby ensuring effects of a high signal to noise ratio and high sensitivity.

The invention discloses an ultra wide band balance filter based on a slotted line structure. The ultra wide band balance filter comprises a first filter and a second filter, wherein the first filter and the second filter are the same in structure, symmetrical to each other and connected on a symmetry plane. The first filter comprises a microstrip line structure and the slotted line structure. The slotted line structure comprises 2N+1 slotted line resonators of linear structures, the length of the 2N+1 slotted line resonators is half of the corresponding wave length of the center frequency of the balance filter, and the 2N+1 slotted line resonators are evenly ranked at equal distances on a first straight line and a second straight line, wherein N is a natural number larger than one. The first straight line comprises the N slotted line resonators, the second straight line comprises the N+1 slotted line resonators, centers of the N slotted line resonators on the first straight line are arranged on spaced central axes between the N+1 slotted line resonators on the second straight line respectively, the 2N+1 slotted line resonators are coupled with one another, and the 2N+1 slotted line resonators and the microstrip line structure form N+2 order filters. The balance filter has the advantages of ultra wide bands, high common-mode rejection, the simple structure and the like.

The invention discloses a network transformer, in which four main magnetic coils of the network transformer are twisted with each other to form a four-core twisted wire, and the four-core twisted wire passes through the center of the main magnetic ring and is evenly wound around the main magnetic coil. The outer components of the ring. The secondary magnetic ring is arranged on one side of the main magnetic ring at a certain distance, and the first secondary winding and the second secondary winding are taken out of the four-core twisted wire of the main magnetic ring. The wires are twisted with each other to form a two-core twisted wire, which is evenly wound on the outside of the secondary magnetic ring to form a common mode choke coil. Each of the primary magnetic rings and each of the secondary magnetic rings form a winding, which suppresses common-mode signals, so that this technical solution realizes network transformer functions such as signal transmission, impedance matching, signal clutter suppression, and high-voltage isolation. .

The invention discloses a single-channel earthquake signal acquisition device. The device comprises a signal input end, a first low pass filtering circuit, a front amplification circuit, an A / D conversion circuit, a controller and a wireless transmission circuit. The invention further discloses a earthquake signal acquisition system, the system comprises multiple geophones and multiple single-channel earthquake signal acquisition devices, wherein output ends of the multiple geophones are respectively connected with signal input ends of the single-channel earthquake signal acquisition devices. The device comprising the first low pass filtering circuit, the front amplification circuit, the A / D conversion circuit, the controller and the wireless transmission circuit is advantaged in that earthquake signal acquisition and wireless signal transmission can be realized. The system is advantaged in that the system is light, is easy to carry and is flexible for operation, earthquake signal acquisition operation efficiency is improved. The device and the system can be widely applied to earthquake signal acquisition fields.

The invention discloses a high-precision measurement method based on a photovoltaic assembly data monitoring system. A signal with a fixed input range is segmented; a single-chip microcomputer is used for controlling connection or disconnection of a switch; and thus a signal with a corresponding range passes through a corresponding channel. Before measurement, a complete signal is divided into a plurality of ones with small ranges; each range is bound with one switch group; and input signal segmentation is realized by connection or disconnection of a switch. Therefore, connection or disconnection of one switch group in an amplification circuit is controlled by the single-chip microcomputer; and other switches are in a disconnection state. Compared with the prior art, the method has the following advantages: the measurement accuracy is high; the fixed range is divided into several ranges; the more segments, the higher the measurement accuracy; with a differential amplifier circuit, a common mode signal is suppressed; and the anti-interference ability is good.

The invention provides steam ablation equipment. The steam ablation equipment comprises a handle, a heating part, a power module, an injection part and a first processing circuit, wherein a containing cavity and a nozzle connected to the containing cavity are formed in the handle, the heating part is arranged in the containing cavity, the power module is electrically connected to the heating part to supply power to the heating part and enable the heating part to emit heat, and the injection part is connected to the containing cavity to inject water into the containing cavity. The first processing circuit comprises a first control module, a voltage comparison module, a temperature comparison module and a protection logic processing module, wherein the voltage comparison module and the temperature comparison module are both electrically connected to the first side of the protection logic processing module, and the first side of the protection logic processing module is electrically connected with the first control module.

The invention discloses a BIM (building information modeling) based building lighting system. The BIM based building lighting system comprises a computer system, and a first luminance sensor and a relay module which are connected with the computer system separately, and an illuminating lamp connected with the relay module; the building lighting system is characterized by also comprising a BIM model information memory, a signal processing module and a display which are connected with the computer system separately, and a second luminance sensor which is connected with the signal processing module. According to the BIM based building lighting system, the second luminance sensor arranged besides the illuminating lamp is used for collecting the luminance of the illuminating lamp; if the second luminance sensor does not collect luminance at night, it shows that the illuminating lamp at the position is in failure; the computer is combined with the internal information of the BIM model information memory to display the location of the illuminating lamp in failure, so that an administrator can maintain or replace the illuminating lamp specifically to eliminate faults in time; and meanwhile, a large amount of manpower is reduced.

The invention discloses a balance type common-mode filter with adjustable broad band. The filter comprises a dielectric substrate, a first metal layer and a second metal layer, wherein the first metal layer is arranged on one surface of the dielectric substrate; a pair of differential microstrip transmission lines are arranged on the first metal layer; the second metal layer is arranged on the other surface of the dielectric substrate; the second metal layer is used as a grounding metal surface, and at least one groove line annular resonator is arranged on the second metal layer; each groove line annular resonator is formed by four groove lines in a surrounding manner, wherein the four groove lines are arranged on the second metal layer, connected in sequence, and distributed along the rectangular four sides; the differential microstrip transmission lines are in axial symmetry relative to a first straight line; the projections of the groove line annular resonators on the second metal layer are all in axial symmetry relative to the first straight line; and a variable capacitor is arranged between one group of opposite groove lines, parallel to the first straight line, of the groove line annular resonators separately. By implementation of the technical scheme of the filter, the common-mode stop band frequency of the balance type adjustable common-mode filter can be adjustable in a bidirectional way by controlling the capacitance values of the two viable capacitors loaded on the groove line annular resonators respectively so as to restrain the target common-mode signal.

The invention discloses a symmetrical integrated laminated transformer, which consists of a substrate, first to third layers of dielectrics sequentially arranged on the substrate from bottom to top, and grid-shaped shielding grids respectively placed in the first layer of dielectrics, The primary coil in the second layer of medium and the secondary coil in the third layer of medium are composed; wherein, the shielding grid is arranged on the lower plane of the first layer of medium; the primary coils are separated from each other and are symmetrical with 2 turns around the axis and arranged in parallel on the lower plane of the second layer of medium; the secondary coils are separated from each other and symmetrically around the axis for 5 turns and arranged in series on the lower plane of the third layer of medium, and the adjacent coils in groups of two The coil is cross-connected with two connecting wires near the axis, and the remaining coil is directly connected with the connecting wire with the metal layer near the axis, and the center tap of the secondary coil is set at the middle point. The symmetrical integrated laminated transformer of the invention has the characteristics of good symmetry, high turns ratio and high magnetic induction coefficient.

The invention discloses a single-converted-to-double low noise amplifier with a highly balanced and stabilized differential output gain phase. The amplifier comprises a common source or common emitter input amplifying transistor pair which comprises a first transistor and a fourth transistor, a common gate or common base amplifying transistor pair which comprises a second transistor and a third transistor, a tail current source pipe and output load circuits with tight coupling differential inductors; a fourth inductor L4 and a fifth inductor L5 are tight coupling differential inductors; C1 and C2 are differential capacitors with the same capacitance values; L0 and L1 also are tight coupling differential inductors. For the amplifier disclosed by the invention, since output loads adopt the tight coupling differential inductors L4 and L5 and the differential capacitors C1 and C2 for resonance, the balance and the stability of the differential output gain phase are improved, and the high-impedance tail current source pipe M5 can well restrain a common mode signal. The amplifier disclosed by the invention has excellent robustness when the PVT (Pressure Volume Temperature) and a working frequency point are changed, and at the same time, the amplifier has an excellent anti-interference capacity for the medium base noise.

The invention belongs to the field of electric appliance circuits, and particularly relates to a common-mode voltage control method for a doubly-fed motor converter. According to the method, a common-mode voltage generation circuit is added on a doubly-fed generator and a converter circuit. The generation circuit adopts a bridge arm and is connected to a direct current bus; a control signal of thecommon-mode voltage injection bridge arm is obtained by adding one third of the sum of SVPWM signals at the power grid side and one third of the sum of SVPWM signals at the motor side, the formula isshown in the description, that is, Vcom_zero2(t)=-Vzero1(t)-Vzero2(t), and in an ideal condition, Vzero1(t)+Vcom_zero2(t)+Vzero2(t)=0. Compared with a traditional common-mode voltage generation circuit, the common-mode voltage generation circuit is small in power and low in cost, and low-frequency common-mode signals vzero1 and vzero2 can be restrained, so that insulation of a motor winding is facilitated, and electric leakage of a rotor bearing and a slip ring is prevented.

The invention discloses an electroencephalogram amplifier which comprises a signal acquisition module, a current amplification module, a differential amplification module and a signal output module, the signal acquisition module comprises a recording electrode, a reference electrode and a ground electrode, and the current amplification module comprises a recording amplifier, a reference amplifier and a ground amplifier, the recording electrode is connected with the first resistor and serves as the front electrode of the recording amplifier, the rear electrode of the recording amplifier is connected with the front electrode of the differential amplification module, the reference electrode is connected with the second resistor and serves as the front electrode of the reference amplifier, the rear electrode of the reference amplifier is connected with the front electrode of the differential amplification module, and the rear electrode of the reference amplifier serves as the front electrode of the ground amplifier, the gain feedback end of the differential amplification module serves as the front electrode of the ground amplifier, and the ground electrode is connected with the third resistor and serves as the rear electrode of the ground amplifier, so that the electroencephalogram amplifier has the characteristic of high input impedance, and meanwhile, an output common-mode signal has an equipotential point and is zero, so that common-mode interference is eliminated, and a higher common-mode rejection ratio is achieved.

The invention discloses a circuit system of a micro-electromechanical hybrid gyroscope. Capacitance signals outputted by the micro-electromechanical hybrid gyroscope pass a differential amplifier and a band-pass filter of a front interface; the signals then pass an analog-to-digital converter, a digital demodulator, a filter, and a decoupling module; the signals are then converted into analogue signals through a digital-to-analog converter. The analogue signals are transformed into feedback voltages through an amplifier; the feedback voltages are superposed with carrier waves and pre-load voltages, and act on a feedback torquer of the micro-electromechanical hybrid gyroscope, such that a rebalance loop is formed. A silicon micro-gyroscope peripheral signal processing circuit realized by analogue signals has the defects of complicated structure, poor flexibility, noise, temperature drift, and the like. With the system provided by the invention, the defects are overcome. The invention provides a micro-electromechanical hybrid gyroscope circuit system which is simple and feasible, and is advantaged in good stability and good portability.

The invention discloses a signal phase lock-type processing system used for an electrolytic tank anode current measuring apparatus. The signal phase lock-type processing system comprises a processing chip U, a signal acquiring device JS, a triode VT4, a polar capacitor C11, a diode D8, the phase-locked loop circuits connected between a COMP base pin and a CS base pin of the processing chip U in series, a second-order low-pass filter circuit connected with the signal acquiring device JS, the emitter coupled logic circuits connected between the second-order low-pass filter circuit and the processing chip U in series, and a linear isolating circuit respectively connected with a OUT base pin and a G base pin and a CLK base pin of the processing chip U. The signal phase lock-type processing system has the advantages of reasonable design, simple integral structure, and good usage effect, and better ensures accurate measurement of the current of an anode rod by the electrolytic tank anode current measuring apparatus.

The invention discloses an open circuit stub loaded coupled line feed-based balance dual-passband filter. The balance dual-passband filter comprises a metal circuit; and the metal circuit comprises acoupled feed network and a resonator. By adopting an open circuit stub loaded type couple feed structure, common-mode signal suppression within a full-frequency range can be realized; and meanwhile, the adopted resonator has two controllable difference module resonant modes, so that dual-frequency difference module band-pass operation can be realized.

The invention discloses a sampling holding circuit applied to a high-speed high-precision circuit. The sampling holding circuit comprises a full-differential type operational amplifier, two sampling capacitors Cs, two sampling switches S1 and five selective switches and a low-pass filter circuit formed by a resistor R1 and a capacitor C1. The full-differential type operational amplifier is a gain enhancement folding cascade full-differential type operational amplifier, a sampling switch S1 is a grid voltage bootstrap switch, connected structures of the positive end and the negative end of the full-differential type operational amplifier are completely same, and a signal input end passes through the low-pass filter circuit to be connected with a lower pole plate of the sampling capacitors Cs through the sampling switches S1. A selective switch S3 is connected with the lower pole plate of the sampling capacitors Cs and the output end of the full-differential type operational amplifier. An upper pole plate of the sampling capacitors Cs is connected with the input end of the full-differential type operational amplifier, a selective switch S4 is connected with upper pole plates of the two sampling capacitors Cs, and a selective switch S2 is connected with the input end and the output end of the full-differential type operational amplifier. The sampling holding circuit can achieve sampling holding of the input signals in the high-speed high-precision circuit.

The invention discloses an LTCC balanced band-pass filter based on multi-frequency coupling, comprising two half-wavelength resonators and two groups of feeders. The two half-wavelength resonators are each composed of micro-strip lines in three different conductor layers, and the micro-strip lines in different conductor layers are connected by metal through holes. First coupling regions (211) of the two half-wavelength resonators are coupled to each other in the form of parallel coupling. The two groups of feeders (501, 502, 503) are disposed in the same conductor layer, and feed second coupling regions (411) of the two half-wavelength resonators under the feeders in the form of vertical coupling. The size of the filter is reduced effectively. The filter has high common-mode rejection ratio. Source-load coupling is introduced between the feeders, three transmission zeros are produced, and the selectivity of pass band is improved.