54 results about "Virtual ground" patented technology

Amplifiers with new circuit topologies for gain shaping and gain control are described herein. An example amplifier circuit with gain control includes a differential transistor pair, a main transistor pair coupled to the differential transistor pair, an auxiliary transistor pair coupled to the differential transistor pair, and a resistive impedance coupled between base terminals of the auxiliary transistor pair. The resistive impedance can include a pair of matched resistors coupled between base terminals of the auxiliary transistor pair. The amplifier can also include a capacitor coupled from a virtual ground node between the pair of matched resistors to ground. The amplifier circuits described herein can present a preferred gain response as compared to other amplifiers, at both midband and peaking frequencies. The amplifier circuits also offer additional options for control of gain at midband frequencies, among other benefits.

The invention relates to the technical field of power equipment state monitoring, and discloses a transformer oil paper insulation frequency domain response online monitoring system which comprises an interface protection module, a modulation control module, a servo balance module and a diagnosis reconstruction module. The interface protection module extracts end screen leakage current and provides overvoltage protection; the modulation control module tracks the bus voltage phase and generates broadband modulation excitation voltage; the servo balance module generates a reverse servo current through closed loop feedback, counteracts a power frequency component in a leakage current so as to maintain a virtual ground state of a measurement node, and injects broadband excitation in a superposed manner; and the diagnosis reconstruction module synchronously acquires signals, reconstructs data in combination with time sequence information, calculates equivalent complex admittance by utilizing cross-correlation demodulation, and outputs complex capacitance and a dielectric loss factor. According to the invention, the operating voltage is used as a carrier wave, strong power frequency interference is eliminated through hardware servo, and safe online excitation is realized by matching with phase chopping, so that the difficult problem of weak broadband signal extraction is effectively solved, and combined monitoring and diagnosis are realized.

A current measurement system, comprising a plurality of parallel sensing circuits, each sensing circuit configured to measure a respective range of voltage corresponding to a current through a load, wherein each sensing circuit is triggered to initiate measurement of a voltage across the load in response to a buffer current through a common buffer reaching a respective threshold, a buffer circuit for inputting a virtual ground voltage or a virtual ground current to the load and to the plurality of parallel sensing circuits, the virtual ground voltage corresponding to the voltage across the load or the current through the load, and a processor coupled to the plurality of parallel sensing circuits, wherein the processor is configured to combine data representing voltage measurements from the plurality of parallel sensing circuits to determine the current through the load.

Methods and apparatus for amplifying a signal via an amplification circuit are described. An example amplification circuit generally includes an amplifier including an inverting input configured to receive a signal for wireless transmission. The amplification circuit also includes an impedance coupled between the inverting input and an output of the amplifier. The amplification circuit further includes a resistive element including (i) a first terminal coupled to the inverting input and (ii) a second terminal coupled to a reference potential node for the amplification circuit.

The invention discloses a low-noise amplifier circuit capable of improving stability and bypass linearity, and relates to the technical field of radio frequency integrated circuits. The circuit comprises an input matching module, a low noise amplification module, an output matching module, a bypass module, a common source electrode switch module and a negative feedback virtual ground module. A leakage path is cut off according to cooperative control of an enable signal and an MOS switch tube through the common source electrode switch module so as to improve the linearity of a bypass mode, and a negative feedback loop network is generated by the negative feedback virtual ground module and the output matching module, so that a high-frequency signal is fed back from the negative feedback loop network, and the linearity of the bypass mode is improved. The problem of stability under high gain is solved.

This invention belongs to the field of microwave communication, specifically disclosing a low-parasitic amplitude modulation differential bridge T-type phase shifter. The ground terminals of the differential positive branch phase shifter circuit and the differential negative branch phase shifter circuit are connected to form a differential virtual ground. A first input port is connected to the input terminal of the differential positive branch phase shifter circuit via a matching circuit, and a second input port is connected to the input terminal of the differential negative branch phase shifter circuit via a matching circuit. The output terminal of the differential positive branch phase shifter circuit is connected to the first output port, and the output terminal of the differential negative branch phase shifter circuit is connected to the second output port. A first insertion loss adjustment circuit is connected in parallel between the matching circuit and the phase shifter circuit, and a second insertion loss adjustment circuit is connected in parallel between the phase shifter circuit and the signal output port. This invention reduces the difference in insertion loss between the bridge T-type phase shifter in the reference state and the phase shifter state, thus reducing parasitic amplitude modulation. This invention is applicable to phase control in phased array radar antenna elements.

The embodiment of the application provides a direct current offset correction method and a correction system, the method comprising: obtaining a first direct current output offset voltage of a complex filter to be corrected; determining a relationship between a direct current input voltage and the direct current output offset voltage under an ideal filter based on a preset virtual ground characteristic of an operational amplifier, according to an input current of an input point of the operational amplifier and a preset resistance of the complex filter; determining a to-be-corrected current according to the relationship between the direct current input voltage and the direct current output offset voltage under the ideal filter and the first direct current output offset voltage, and working under a normal working condition by using the to-be-corrected current; and based on the preset virtual ground characteristic of the operational amplifier, performing one or more iteration calculations on the input current of the input point of the operational amplifier, the preset resistance of the complex filter and the to-be-corrected current, so that a second direct current offset voltage is a preset value, the IQ structure of the complex filter is not damaged, and the I / Q two paths can be simultaneously corrected, and one-step correction is completed.

The application provides a power supply filtering circuit, a power supply module and an electronic device, and belongs to the field of switching power supplies. The power supply filtering circuit comprises a low dropout linear regulator (LDO) and a virtual ground voltage generating circuit. An input end of the LDO is used to receive an input voltage as an input end of the power supply filtering circuit, and an output end of the LDO is used to output an output voltage as an output end of the power supply filtering circuit; an input end of the virtual ground voltage generating circuit is coupled with the input end of the LDO, and an output end of the virtual ground voltage generating circuit is coupled with a ground end of the LDO; the virtual ground voltage generating circuit is configured to output a virtual ground voltage to the ground end of the LDO, and the virtual ground voltage changes in the same direction as the input voltage, so that the LDO is in a normal working state. The application embodiment enables the LDO to still work normally in the filtering scene of dynamic high-voltage input or wide-voltage input range.

The present application relates to the technical field of engineering construction simulation, in particular to a power transmission and transformation engineering construction simulation method based on digital twinning. When a misoperation occurs in the disassembly process, the simulation system can calculate the virtual construction stress change in real time and judge whether a falling collision abnormal situation is likely to occur. When a collision occurs, the collision impulse is calculated based on the relative speed, the rebound behavior of the virtual construction after the collision is controlled in combination with the rebound coefficient, and the tangential motion is simulated by using the friction force to ensure the reasonable motion trajectory of the virtual construction equipment on the virtual ground. The immersive interactive scene and the future time pre-response mechanism enable the user to experience the possible construction risks in the virtual environment in advance, warn of possible dangerous operations in advance, and provide optimization suggestions, so that the construction personnel can identify before actual operation, improve the decision-making ability and avoid risks in a timely manner.

The present disclosure relates to an amplifier device for amplifying an input signal Sx at a device input X to an output signal Sy at a device output Y, for driving a loudspeaker or comparable reactive load, comprises a self-oscillating Class D power amplifier stage with transfer function KA(s). The amplifier stage includes a comparator, a power stage, and a second-order low-pass output filter comprising an inductor and a capacitor. A time delay unit provides a delay determined by one or more of the comparator, the power stage, and a first feedback filter. The output signal Sy is fed back to the comparator via the first feedback path to establish oscillation and provide basic low-frequency feedback. A correction stage is provided, comprising a second feedback path that feeds the output signal Sy, via a scaling resistor, to a virtual ground input of a transimpedance amplifier.

The invention provides a differential power amplification stage comprising a first amplification unit adapted to amplify a first differential signal and to output an amplified first differential signal, a second amplification unit adapted to amplify a second differential signal having opposite phase to the first differential signal and to output an amplified second differential signal, and a saturation detection unit adapted to detect gain saturation of the first and second amplification unit, to generate a saturation detection signal indicating the gain saturation of first and second amplification unit, and to provide a virtual ground for the first and second differential signals for RF cancellation on the first and second differential signals. The virtual ground principle is also applied to a Doherty power amplifier module which comprises a saturation detection unit for detecting saturation in the carrier amplification stage.

The present invention discloses a readout circuit based on an embedded CCIA and a hybrid DSM. The readout circuit includes an embedded CCIA and a hybrid DSM. The embedded CCIA is embedded in the loop of the hybrid DSM, and the virtual ground point of the embedded CCIA serves as the summing node for the input differential signal and the feedback differential signal. The hybrid DSM includes an RC integrator, a first SC integrator, a second SC integrator, a 1.5-bit quantizer, and a feedback DAC. The RC integrator is a CT integrator, which reduces the bandwidth requirements for the CCIA; the SC integrator is a DT integrator, which reduces sensitivity to excessive loop delay and RC coefficient variations, reduces the impact of PVT, and improves the robustness of the ROIC. The hybrid DSM facilitates the implementation of a high-efficiency, high-precision readout circuit.

The invention discloses a laboratory sunlight energy-saving illumination management system, belongs to the technical field of energy-saving illumination, and solves the problems that a solar simulator bus is out of control due to bidirectional power conflict, an experiment is failed due to light ripple pollution, and energy conservation is more wasted. Comprising a multi-phase magnetic energy cyclic matrix module which generates a controlled multi-phase alternating current energy field; the rotating field transformer energy transfer device module is used for directionally distributing energy in a multi-phase alternating current energy field to each output channel according to a real-time instruction; the distributed virtual ground bus framework module is used for maintaining the power supply reference potential of each output channel; and the digital pre-distortion compensator module is used for performing nonlinear and memory effect compensation on an input instruction and sending the compensated instruction to the multi-phase magnetic energy cyclic matrix module. According to the invention, the rotating magnetic field is coupled with the distributed wireless energy network to decouple the power flow, the noise is suppressed, the spectrum is independent, the energy is saved, and repeated experiments are avoided.

This invention discloses an intelligent discharge device based on non-contact coupling and remote monitoring, relating to the field of high-voltage power equipment safety protection technology. It includes: a non-contact electrode module for generating a high-frequency magnetic field to establish a coupling channel, releasing the charge of the charged body into a virtual grounding loop through electromagnetic induction; a high-frequency energy conversion module for converting the charge of the charged body into a high-frequency pulse signal; an energy storage and release module for absorbing and neutralizing the charge coupling formed between the insulation layer and the charged body through a high-voltage capacitor matrix; a multi-dimensional sensing module for acquiring electric field, temperature, partial discharge, and voltage level and phase information of the charged body; an edge intelligent processing module for achieving adaptive optimization and fault self-diagnosis of the discharge process; and a dual-mode communication system for uploading discharge current, voltage waveform, and status data to a cloud platform in real time. This invention achieves adaptive discharge and remote monitoring of the charged body through hardware collaboration and algorithm optimization.

A capacitive sensing charge amplifier, e.g., in a direct current (DC) feedback network, may incorporate a switching capacitor, including a first control switch and a second control switch, which receives a switching signal to charge and discharges the switching signal to a virtual ground of a sense amplifier. Noise incorporated into the output of the sense amplifier (e.g., a MEMS output signal) is filtered by a demodulation signal at a demodulator such that the period average noise at the demodulator output equals zero. The time varying nature of the switching capacitor resistance generally reshapes the system's post-demodulation noise to reduce its low frequency output noise.

The invention relates to the technical field of image processing, and discloses a shadow rendering method and device, equipment and a storage medium. The shadow rendering method comprises the following steps: projecting the contour of a foreground image matting to a virtual ground in a preset virtual three-dimensional scene to generate a shadow projection; comparing visual depths of overlapped pixels in the shadow projection and the foreground matting to adjust a visible range of the shadow projection; and carrying out color mixing on the shadow projection in the visible range and the overlapped pixels of the virtual ground so as to render the shadow projection in the visible range to a preset virtual three-dimensional scene. By means of the method, the shadow effect of foreground image matting can be rendered in the virtual three-dimensional scene, and the sense of reality of shadow rendering and the real-time rendering efficiency are improved.

The application discloses a single-end voltage-stabilized liquid level signaler with adjustable hysteresis and a liquid level measuring method. The liquid level signaler comprises a capacitive liquid level sensor and a signal processing module. The signal processing module comprises a voltage stabilizing circuit, a virtual ground processing circuit, a liquid level sensing conversion circuit, a hysteresis comparison circuit and a signal output circuit. The liquid level sensing conversion circuit comprises a signal generating circuit, a signal excitation circuit and a comparison amplifying circuit. The voltage stabilizing circuit and the virtual ground processing circuit are respectively used for linear voltage stabilization and virtual ground generation of a single-end power supply, serving as a reference voltage of the latter circuit. The liquid level signaler only needs single-end power supply, and the fluctuation within a certain range does not affect the output of the latter, so that the quality and quantity of the on-board power supply are required to be lower. The application has controllable hysteresis comparison function and can effectively filter, so as to realize hardware dithering, greatly solve the occurrence of false alarm and have good practicability.

The invention belongs to the technical field of new energy grid connection, and discloses a modeling method and a related device for a grid-connected system of a multi-constructed-network converter, and the method comprises the steps: decomposing the system into two key sub-modules, namely a constructed-network converter module and a network module, and carrying out the precise description of each module through employing a state space model, thereby achieving the modeling of a multi-constructed-network converter grid-connected system. And then a virtual grounding resistor is introduced at an interconnection node of the multi-network-construction-type converter grid-connected system, and the small signal state space model of the network-construction-type converter module and the small signal state space model of the network module are integrated, so that a small signal state space model of the multi-network-construction-type converter grid-connected system is obtained. According to the modular modeling mode, the flexibility and expandability of the model are remarkably improved, the model can easily adapt to grid-connected systems of different scales and configurations, the complexity of system modeling is greatly reduced, and the modeling time and cost are effectively saved. In addition, a clear theoretical framework is provided for system stability analysis, and efficient and stable operation of the grid-connected system can be achieved.

An ion wind-assisted electrostatic printing nozzle structure and method for micro / nano structures on insulating substrate surfaces includes an electrostatic printing nozzle, with an ion wind generating module coaxially connected to the outer side of the nozzle. The inlet at the top of the nozzle is connected to a driving air pressure source, and the nozzle at the bottom is connected to a high-voltage power supply. The ion wind generating module has a built-in ionization electrode that generates positive and negative ions upon applying a high voltage. These ions are then driven by airflow to form an ion wind, which is focused on the printing area below the nozzle, keeping the insulating substrate surface in a near-zero potential state, thus forming a virtual grounding electrode. This invention utilizes ion wind to construct a virtual grounding electrode on the insulating surface, solving the problem of unstable electric field during printing caused by variations in printing height and charge accumulation on the insulating surface, thereby improving the applicability of electrostatic printing to insulating substrates.

A differential amplifier circuit comprising a PWM modulator for generating a PWM signal representative of a difference between the first and the second staircase like reference signals and the digital input signal, a DM-IDAC for receiving the PWM signal and providing a first and second differential mode current, a CM-IDAC for receiving the PWM signal and providing a common mode current, first and second loop integrators, and first and second comparators; each loop integrator comprising virtual ground node terminal for receiving the differential mode current, the common mode current, and a feedback signal from an output stage of the differential amplifier circuit via a feedback loop, and integrator output terminal for providing loop integrator output signal proportional to an integral of the signals received at the virtual ground node terminal, the comparators receiving the loop integrator output signal, triangular reference signal, and providing drive signal to output stage.

The application relates to a method and system for a pilot directional protection of LCC-HVDC lines based on virtual grounding resistance. The method comprises: Obtaining a conduction state information of a converter and characteristic parameters of a converter circuit within one commutation period after a fault occurs; according to the conduction state information and characteristic parameters, determining characteristic frequency of the circuit; according to the characteristic frequency and characteristic parameters, determining a virtual grounding resistance; according to the virtual grounding resistance, determining fault areas.

The present disclosure relates to a map data processing method, device, equipment, medium and product, the method comprising: acquiring map data of a first region and map data of a second region, the first region and the second region being obtained by different batches of collection, and there being an edge region of repeated collection, the map data comprising point cloud data; acquiring a pre-set virtual ground control point, the virtual ground control point being located in a recording block of the first region adjacent to the second region; based on the virtual ground control point, the map data corresponding to the recording block is split to obtain split map data of the first region and split map data of the second region; and taking the point cloud data associated with the virtual ground control point as a reference, the position of the point cloud data in the split first region and the point cloud data in the split second region are aligned. In this way, the data alignment between regions is decoupled, the position alignment of multiple regions can be performed at the same time, and the data waiting period is shortened.

The present invention aims to provide a method for estimating the amount of subsidence, a building reinforcement method, and a display control device that can estimate the amount of subsidence with high accuracy regardless of the number of layers expected to subside, while keeping costs down. [Solution] The method includes steps of identifying the lower and upper end points of each of multiple expected subsidence layers at multiple set positions BP, constructing a virtual ground model including multiple expected subsidence layers, and calculating the expected amount of subsidence at multiple expected pile driving positions PP from the virtual ground model.

To provide a self-oscillating Class-D amplifier device which implements the improvement of acoustic performance, the reduction of distortion and the improvement of stability.SOLUTION: An amplifier device 300 for amplifying an input signal Sx at a device input X to an output signal Sy at a device output Y, for driving reactive load such as a loudspeaker, comprises a self-oscillating Class-D power amplifier stage K with transfer function KA(s). The amplifier stage includes a comparator, a power stage, a second-order low-pass output filter and a time delay unit. The time delay unit provides a delay determined by the comparator, the power stage, and a first feedback filter Hosc. The output signal Sy is fed back to the comparator via a first feedback path. A correction stage comprises a second feedback path that feeds the output signal Sy to a virtual ground input of a transimpedance amplifier. A third feedback path for further enhancing correction includes a passive network which applies a first transfer function H2 to the output signal Sy and applies a second transfer function H3 to the input signal Sx.SELECTED DRAWING: Figure 2

The embodiment of the invention provides a transformer area identification device and system, the transformer area identification device comprises a relay assembly and a controller which are connected, the relay assembly is connected with a power supply, and the output end of the relay assembly is connected with virtual ground; the relay assembly comprises a first relay, a second relay and a third relay which are sequentially connected in series; the controller is configured to: control to disconnect all the phase lines; and circularly executing the steps of controlling to close one phase line and injecting the identification signal into the closed phase line until the identification signal is injected into all the phase lines, so as to transmit the identification signal to the intelligent electric meter in the transformer area through each phase line. Wherein the identification signal comprises a unique identity code of the transformer area, and the intelligent electric meter in the transformer area sends the identification signal to the data acquisition equipment, so that the data acquisition equipment identifies the intelligent electric meter in the transformer area according to the received identification signal. According to the invention, the accuracy of transformer area identification can be effectively improved.

The invention belongs to the technical field of capacitive voltage dividers, and particularly relates to a capacitive voltage divider based on an operational amplifier, which comprises a high-voltage capacitor, a low-voltage capacitor, a shielding structure, the operational amplifier and a double-T-shaped resistance-capacitance network, the high-voltage capacitor and the low-voltage capacitor are connected in series; the shielding structure is grounded and is used for shielding electric field coupling between the high-voltage capacitor and the ground; the positive input end of the operational amplifier is grounded, and the inverted input end and the output end of the operational amplifier are connected to the two ends of the low-voltage capacitor respectively. High-voltage and low-voltage capacitor series nodes are virtually grounded through operational amplifier negative feedback, a feedback circuit is not needed to compensate shielding potential, and additional errors are thoroughly avoided; and meanwhile, a rear-end high input impedance design is not needed, so that the circuit complexity and the hardware cost are reduced.

The invention relates to the technical field of digital image processing, and discloses an analog data generation and evaluation method and system for hyperspectral unmixing algorithm performance, and the method comprises the steps: generating an initial random grid based on a random seed; processing the initial random grid to generate a virtual ground feature distribution scene graph; processing the virtual ground feature distribution scene graph to obtain an initial abundance graph; performing superposition and normalization processing on a plurality of initial abundance maps generated based on the same random seed and different filtering parameters to generate a final abundance map; screening a group of end member spectrums, and monitoring the spectrum similarity between the end members; performing spectrum variation modeling on the screened end member spectrums to generate an end member spectrum set; according to the final abundance graph and the end member spectrum set, generating preliminary simulation spectrum data; adding noise into the preliminary simulation spectrum data to generate a final hyperspectral simulation data set, and evaluating the performance of the hyperspectral unmixing algorithm by using the data set, so that the objectivity and comprehensiveness of evaluation can be improved.

A differential amplifier circuit is provided. The circuit includes a PWM modulator for generating a PWM signal representative of a difference between the first and the second staircase-like reference signals and the digital input signal, a DM-IDAC for receiving the PWM signal and providing a first and second differential mode current, a CM-IDAC for receiving the PWM signal and providing a common mode current, first and second loop integrators, and first and second comparators; each loop integrator comprising virtual ground node terminal for receiving the differential mode current, the common mode current, and a feedback signal from an output stage of the differential amplifier circuit via a feedback loop, and integrator output terminal for providing loop integrator output signal proportional to an integral of the signals received at the virtual ground node terminal, the comparators receiving the loop integrator output signal, and triangular reference signal.

Systems and methods that integrate a directional coupling function with directivity that does not have output loss are disclosed. For example, a power amplifier circuit arrangement includes an input terminal to receive an input signal; amplifier circuitry including a first amplifier stage, a second amplifier stage, and a virtual ground node, where an input of the first amplifier stage is coupled to the input terminal, an output of the first amplifier stage is coupled to an input of the second amplifier stage via the virtual ground node, and an output of the second amplifier stage is coupled to the input of the first amplifier stage via feedback circuitry; an output terminal coupled to the output of the second amplifier stage, the output terminal to output an amplified signal; and a directional coupler terminal coupled to the virtual ground node.

A system for acquiring electrocardiogram (ECG) pulses from a subject, comprising: a virtual ground; and a plurality of measurement nodes connectable to a plurality of corresponding ECG electrodes, wherein the plurality of measurement nodes are connected to the virtual ground, and wherein each measurement node comprises: a voltage-to-frequency converter (VFC) configured to convert an ECG signal from the corresponding ECG electrode to a frequency signal; an optical converter configured to convert the frequency signal from the VFC to an optical signal, and to output the optical signal via an output fiber-optic cable; and a DC power converter configured to receive a modulated optical signal via an input fiber-optic cable, to recover DC power from the modulated optical signal, and to supply the DC power to at least the VFC and the optical converter.