1235 results about "Differential amplification" patented technology

A receiver circuit includes a first differential amplification unit including a variable load section, and configured to receive first and second input signals, and to generate first and second output signals, which are amplified based on an impedance value of the variable load section and a voltage difference between the first and second input signals, a second differential amplification unit configured to receive the first and second output signals and to generate a third output signal based on a voltage difference between the first and second output signals, and a signal generating unit configured to generate an equalization signal for controlling the variable load section based on the third output signal.

The present invention relates to an optical interferometric apparatus and method for measuring acceleration, pressure, and pressure of fluids during flow using micro-opto-electro-mechanical-systems (MOEMS). The high-sensitivity and high-resolution apparatus includes a movable mass, a stationary mass, a light source, and a photo detector. The light source emits a beam which is converted into two beam portions after impinging onto the movable and stationary masses. Interference between the beam portions are used to measure acceleration or pressure. The MOEMS structure may be integrated with a photo detector or planar waveguide. Differential amplification can be realized by employing two similar detecting structures.

The semiconductor device includes a nonvolatile memory, having a memory array containing 1-bit twin cells, each composed of electrically rewritable first and second storage devices, the first and second storage devices holding binary data according to difference of their threshold voltages, and having different retention characteristics depending on difference of the binary data thereof; a read circuit for differentially amplifying complementary data output from the first and second storage devices of the twin cell selected for read, and judging information stored in the twin cell; and a control circuit. Two memory cells constituting a twin cell are arranged to hold different data. Therefore, even when the retention performance of one memory cell deteriorates, the difference between data held by the two memory cells can be maintained. Hence, differential amplification of such difference enables acquisition of proper stored information. Thus, retention performance of an electrically rewritable nonvolatile memory cell is improved.

An improved rotary servovalve system employs a rotary magnetic solenoid having an armature that includes at least one permanent magnet. The armature is rotatable relative to a stator formed as an electromagnet which is energizable to create alternative electromagnetic fields having opposite polarities from each other. When deenergized, the stator allows the armature to return to a neutral, null position from positions of extreme rotation in opposite angular directions due to the magnetic force of the permanent magnet of the armature. The armature is coupled to carry a movable valve element in angular rotation therewith, so that flow through the servovalve of the system can occur in alternative directions. Also, the valve element is biased toward a position in which all of the valve ports are closed when power is removed from the rotary solenoid. The control circuit employed in the rotary servovalve system expands the bandwidth of response of the solenoid actuator by compensating for frequency variations in the input command signal and in the feedback signal. This compensation is achieved utilizing a combined proportional, integral, and differential amplification circuit. Also, imbalance of fluid forces within the servovalve mechanism can be avoided by utilizing a pair of inlet orifices, a pair of outlet orifices, a pair of first fluid control orifices, and a pair of second fluid control orifices. The orifices within each pair are located on opposite sides of the valve housing from each other.

The invention relates to a DC-to-DC converter with a temperature compensation circuit. The temperature compensation circuit is arranged between a feedback differential amplification circuit and an output voltage detection circuit of the DC-to-DC converter and is used for compensating the voltage level of the DC output voltage of the DC-to-DC converter caused by the change of the environmental temperature. The temperature compensation circuit comprises a temperature detection circuit used for detecting the environmental temperature and generating a temperature signal according to the detection result, and a current source circuit connected between the feedback signal input terminal of the feedback differential amplification circuit and the output voltage detection circuit, wherein the current source circuit can generate a current value according to the temperature signal generated by the temperature detection circuit, form a compensative voltage proportion to the current value and apply the compensative voltage to the DC output voltage, thereby regulating the voltage value of the DC output voltage. The temperature signal generated by the temperature detection circuit is a temperature signal with positive temperature characteristics or a temperature signal with negative temperature characteristics.

The invention discloses a DC (direct current) loop-current suspension device for an inverter parallel system. According to the invention, a DC loop-current control device is added to the control circuit of the existing inverter parallel system, the DC loop-current control device is composed of a voltage DC component suspension circuit. Each inverter module in the parallel system has an independent DC component suspension circuit, a voltage DC component feedback quantity can be obtained through carrying out differential amplification sampling, low-pass filtering and proportional integral regulation on high-frequency PWM (pulse width modulation) wave between an inverter half-bridge midpoint and a dividing capacitor midpoint, a DC component deviation can be obtained through the comparison between the voltage DC component feedback quantity and a voltage DC component reference value, and the DC component deviation is added to an inversion reference voltage, and then the voltage DC component of each inverter can be controlled to be zero through correcting the inversion reference voltage, so that the DC loop-current of the parallel system can be controlled to be zero. The device disclosed by the invention has simple structure and is convenient to implement; and by the adoption of the invention, the characteristics of the original parallel system are maintained, and the DC loop-current of the parallel system can be eliminated.

The invention discloses a tetra-rotor aircraft attitude obtaining method by use of a three-order approximation Picard quaternion. The method comprises the following steps: (1), according to the three-order approximation Picard quaternion, performing attitude solution so as to prevent a gyroscope from integration accumulative errors and reduce differential amplification of noise; and (2), performing Kalman filtering on an attitude angle obtained through the solution so as to effectively filter sensor measuring errors caused by vibration of a tetra-rotor aircraft body and obtain a more accurate attitude angle. The attitude solution method provided by the invention can perform accurate attitude estimation on a miniaturized tetra-rotor aircraft.

The invention provides a device which relates to road vehicle information measuring field. Said device comprises a GMR sensor, a filter denoising unit, a differential amplification unit, a DC bias unit, a second-level amplification unit, a blocking filter unit, a hysteresis comparison unit, a dynamic adjustment unit, a control unit and a RF unit. Said realization method is: a bias magnetic field is set beside the GMR sensor, the sensor output changes when a car passing by the magnetic field; the device judges the passed car through the changes by using the sensor, and transmits the measured vehicle flowrate into base station through RF and controls or saves. The device has broad prospect in road vehicle measuring, park management, road crossing management etc.

The present invention provides a power supply device which can suppress a voltage drop of the input power supply immediately after recovery from shutdown status. The power supply device comprises a reference voltage generation circuit for generating reference voltage (VREF), a transistor for feeding disposed between an input terminal (VTT_IN) and an output terminal (VTT output terminal), a transistor for discharging disposed between a ground potential and a VTT output terminal, a first and second differential amplification circuits for controlling the transistors for feeding and discharging respectively by inputting the output power supply voltage (VTT) as feedback and comparing it with VREF, and a shutdown recovery circuit for generating voltage that gradually starts up by a constant current source and a capacitor, wherein the first differential amplification circuit compares VTT with the voltage (SR) of the shutdown recovery circuit instead of VREF, for a certain period from the point of recovery from shutdown status.

The present invention relates to methods and devices to control and operate the functionality of a power amplifier system (100) capable of operating in at least three differential amplification modes. The drive signal's amplitude envelope controls an integrated switch network (104; 105, 106) that routes both the signal envelope and signal phase to different modulation blocks (111, 112: 109, 110: 115). Depending on the envelope strength, the operational mode of the amplifier system is possible to alter to best serve the signal statistics to provide the highest overall power efficiency.

A liquid crystal drive device having a differential-type input circuit including a differential amplification stage for receiving a differential signal and a buffer stage for generating an output signal on the basis of an output of the differential amplification stage, the liquid crystal drive device for receiving a signal of display data via the input circuit and outputting a signal for driving a liquid crystal panel on the basis of the display data, wherein a liquid crystal driving voltage VLCD larger than a power supply voltage VCC for logic to be supplied to the operation voltage buffer stage is supplied to the differential amplification stage of the input circuit. A standby function of interrupting an operation current of the differential amplification stage in a period where no display data is received is provided.

The invention discloses a differential D-dot voltage sensor, which comprises a measuring module, an electrode plate, a signal modulation module and a collection transmission module, wherein the measuring module is provided with a first input end and a second input end, the electrode plate is provided with a first electrode and a second electrode, the measuring module is a differential amplification module, the differential amplification module is used for measuring the differential voltage between conducting layers, the sensor is not in grounding contact and is also not in direct contact with a tested conductor, and the output is floating potential difference, so the sensor can reduce the size of an insulation structure. Because the differential structure carries out non-contact measurement on the same potential, no direct energy transmission exists between the tested conductor and the sensor, and the influence cannot be generated on the input side when the sensor generates fault such as insulation breakthrough or output short circuit. The differential D-dot voltage sensor can solve the non-contact electrodeless voltage measurement problem of an intelligent electric network and can be used for 10kV to 35kV voltage measurement.

The invention discloses a device and a method for rapidly detecting surviving unicellular organisms in ship ballast water. The device comprises a PDMS micro-fluidic chip and glass substrate G, wherein the PDMS micro-fluidic chip comprises a liquid storage hole A, a liquid storage hole B, a liquid storage hole C, a liquid storage hole D, a liquid storage hole E, a main channel, a first focusing channel, a second focusing channel, a detection channel, a first sorting channel and a second sorting channel, wherein the liquid storage hole A, the liquid storage hole B, the liquid storage hole C, the liquid storage hole D and the liquid storage hole E are inserted into a platinum electrode. The device has the beneficial effects that (1) full-automatic detection, sorting, counting and size determination of the surviving unicellular organisms in the ship ballast water are realized on the micro-fluidic chip, and the device is small in size and is portably and rapidly used for on-site analysis; and (2) a differential micro-fluidic chip and a signal differential amplification mechanism are adopted, and the signal to noise ratio of a detection signal can be improved, so that the detection precision is improved.

An amplitude control device for a signal output by an oscillator includes a rectification circuit for rectifying the output signal, and a differential amplification circuit for generating a biasing current control signal for the oscillator. The biasing current control signal is based upon the output signal from the rectification circuit and a reference voltage. A dividing bridge and an adder are designed so that only a fraction of the reference voltage is used to define the amplitude of the oscillations. The contribution made to the oscillator phase noise by the reference voltage noise is considerably reduced.

The invention, which belongs to the MEMS field, discloses a micro-mechanical resonant electrometer with ultra-high sensitivity. The method comprises a mechanical structure design method of an electrometer header and a testing circuit design method. Compared with the prior art using a movable resonator charge input polar plate, the mechanical structure design enables the conversion efficiency between the electrostatic force and the axial stress to be improved; and with a micro-mechanical lever, the electrostatic force increases to improve mechanical sensitivity. When an external charge is inputted, rigidity disturbance on a resonator I increases and thus the localization phenomenon of the mode becomes dramatic. Meanwhile, the two provided resonators with different structures employ differential detection structures; the differential amplification circuit is used for detecting the amplitudes of the resonators and eliminating feed-through signals, so that the signal to noise ratio of the detection signal can be improved. In terms of the testing circuit design, a closed-loop testing plane is employed. To be specific, a signal at a detection electrode passes through a trans-impedance amplifier, a subtracter, a band-pass filter and a comparator and then is loaded at an alternating-current drive electrode to form a closed loop; rectification and filtering are carried out on two paths of outputs of the subtracter and dividing is carried out to obtain a direct-current voltage signal reflecting an amplitude ratio of two resonators. With a closed-loop drive detection circuit, the amplitude and frequency noise of the resonator can be reduced.

The invention discloses a ranging method based on measurement of the laser pulse flight time. According to the ranging method based on the measurement of the laser pulse flight time, based on the synchronous clock pulse measurement method, a self-adaptive gradient adjustment slope generator and a differential amplification circuit are adopted, not only can the time duration of the part, synchronous with a system clock, in the laser pulse flight time be accurately measured, but also that the time duration of the part, not synchronous with the system clock, in the laser pulse flight time can also be measured extremely accurately, and thus accurate measurement of a target distance is achieved. The time difference ta between the moment when laser is emitted and the nest rising edge of the system clock and the time difference tb between the moment when the laser returns and the next rising edge of the system clock are linearly converted into a voltage V1 and a voltage V2 respectively, a digital value in linear proportion to ta-tb is output after differential amplification and AD conversion, calculation errors caused by data truncation can be effectively avoided, measurement errors caused by factors such as circuit nonlinearity can be effectively reduced through self-adaptive gradient adjustment conducted through the slope generator, and the ranging method is suitable for ranging occasions with the high accuracy requirement.

According to one embodiment, a storage device includes a rotary actuator, vibration detectors, an analog operation circuit, an analog-to-digital converter, and a rotation vibration compensation controller. The rotary actuator positions a head with respect to a storage medium to perform reading or writing. The vibration detectors are located substantially on both sides of the rotation center of the rotary actuator, detects rotation vibration component of a one-axis direction, and outputs a vibration detection signal. The analog operation circuit calculates a rotation vibration detection signal proportional to rotation vibration disturbance applied to the rotary actuator by differential amplification of the vibration detection signal. The analog-to-digital converter converts the rotation vibration detection signal into a digital signal and outputs rotation vibration detection data. The rotation vibration compensation controller controls the rotation vibration disturbance applied to the rotary actuator to be eliminated based on the rotation vibration detection data.

Provided is a bioelectric signal measurement apparatus that obtains an alternate current component and a direct current component of a bioelectric signal. The apparatus includes a plurality of biomedical electrodes, a switch unit, a differential amplification unit, a bioelectric signal extraction unit, and a timing control unit. The plurality of biomedical electrodes are brought into contact with a living body surface and disposed separately from each other. The switch unit short-circuits the biomedical electrodes via a predetermined short-circuit resistance. The differential amplification unit is connected to the biomedical electrodes and amplifies a difference of electric signals therefrom. The bioelectric signal extraction unit extracts a bioelectric signal from an output signal of the differential amplification unit from the release of short-circuit between the biomedical electrodes to the next timing of short-circuiting. The timing control unit controls timings for short-circuiting the biomedical electrodes and releasing the short-circuit therebetween, which are repeated.

A differential transimpedance amplifier circuit for correlated differential amplification. The amplifier circuit increase electronic signal-to-noise ratios in charge detection circuits designed for the detection of very small quantities of electrical charge and / or very weak electromagnetic waves. A differential, integrating capacitive transimpedance amplifier integrated circuit comprising capacitor feedback loops performs time-correlated subtraction of noise.

A gas detection apparatus A comprises a signal processing circuit 20, a Wheatstone bridge circuit 21, integrating circuits 22 and 23, a differential amplification circuit 24, a direct current power supply circuit 25, a heater voltage application circuit 26. The Wheatstone bridge circuit 21 is configured of parallel combination of series circuits: one composed of a catalytic combustion type gas sensor 1 and a load resistor R1, and the other composed of a resistor R2, a variable resistor VR1 and a resistor R3. The heater voltage application circuit 26 is configured to generate a pulsed heater voltage by switching a direct current voltage of the direct current power supply circuit 25 through a transistor TR1 for applying the pulsed heater voltage to the Wheatstone bridge circuit 21. The integrating circuit 22 integrates a voltage at a connection point between the gas sensor 1 and the load resistor R1. The integrating circuit 23 integrates a voltage at a connection point between the variable resistor VR1 and the resistor R3. The differential amplification circuit 24 is configured to amplify a differential voltage between the output voltages of the integrating circuits 22 and 23. The signal processing circuit 20 is configured to determine a concentration of a flammable gas from an output voltage of the differential amplification circuit 24.

The invention discloses a linear electrostatic sensor array method for measuring particle speed and a device thereof. The method comprises the following steps: a duct is axially provided with a first linear electrostatic sensor array and a second linear electrostatic sensor array which are composed of a plurality of ring electrodes; when charged particles pass through the two electrostatic sensor arrays, two sets of electrostatic signals, which reflect gas-solid flow information, are generated; after the electrostatic signals are accessed into a front charge differential circuit to be amplified, a data acquisition circuit sends the amplified signals into a computer; and the computer carries out spectral analysis on the differential electrostatic signal and determines the peak frequency on the frequency spectrum, thereby obtaining the average speed of gas-solid two-phase flow particles. Compared with the single ring electrostatic induction spatial filter, the linear electrostatic sensor array has higher space selectivity, thereby enhancing the measurement accuracy of the particle speed. The device comprises a measuring probe, a front charge differential amplification circuit, a data acquisition card and a computer.

An AGC circuit suitable for applications such as an optical receiving apparatus includes a differential amplification adjustment circuit section for operating on a pair of input signals to produce a corresponding pair of complementary controlled output signals having a fixed amplitude, a peak detector for detecting a peak value of at least one of the controlled output signals, a DC monitoring circuit for detecting the DC level of at least one of the controlled output signals, and an amplitude fixing control circuit for deriving a value of voltage difference between the peak value and DC level and for generating an amplitude control signal based on comparing the voltage difference with a reference voltage. The differential amplification adjustment circuit section applies a degree of amplification that is determined by the amplitude control signal, to thereby perform feedback control of the output signal amplitude. The AGC circuit can further be configured to control the DC levels of the controlled output signals, so that both DC level and amplitude of the controlled output signals are held constant against changes in DC level and amplitude of the input signals.

The invention discloses a sine-cosine encoder high precision signal processing system and method. The method is used for processing Asin[alpha] and Bcos[alpha] of a 90-degree phase difference output by an incremental rotary encoder; encoder signals Asin[alpha] and Bcos[alpha] are firstly subjected to differential amplification and shaping filtering; then coarse code counting is carried out to obtain coarse code information, and a real-time fine interpolation position value is obtained through an electronic subdivision method based on the fact that the arc tangent value is directly calculated with the coordinate rotation digital algorithm; and finally, the coarse code information and the real-time fine interpolation position value are integrated to obtain the high-precision angular position and the high-precision angular speed of a motor. The invention solves the technical problem of carrying out refinement of any multiple of an original signal, and achieves any refinement in theory, and thus the rotor real-time angular value (rad) and the rotor real-time speed value (rad / s) higher than the resolution of the original signal are obtained through calculation. The invention also discloses a system employing the method.

The invention provides a single-photon avalanche diode quenching circuit based on an offset control differential amplification structure. A gate control circuit is used for receiving a gate control enable signal input externally to be in the closed or opened state. A rapid reset circuit is used for receiving a reset signal input externally while the gate control circuit is in the opened state so that the gate control circuit can be in the closed state. When an SPAD detects that a photon generates avalanche current, the avalanche current flows through a detection resistor to generate voltage drop. A low voltage detection circuit adopts the differential amplification structure based on offset control and is used for inducting changes of the input end voltage; when the input end voltage is larger than a detection threshold value of the low voltage detection circuit, output end signals become low-level signals, the detection resistor is controlled to be switched off, and meanwhile a rapid quenching circuit is closed; the rapid quenching circuit is used for accelerating the quenching process when closed, so that the avalanche current is quenched. In the quenching circuit, the detection threshold value of the quenching circuit can be smaller than the turn-on voltage of an NMOS transistor.

The invention relates to a six-order continuous band-pass sigma-delta closed-loop control circuit for an MEMS (micro-electromechanical system) gyroscope, which belongs to the field of guide or control devices using Coriolis effect. The six-order continuous band-pass sigma-delta closed-loop control circuit comprises a charge amplifier 5, a high-pass filter 6, a diode 7, a low-pass filter 8, a fully-differential amplification circuit 9, a phase compensation circuit 10, a resonant circuit 11, a digital conversion 12, an analog switch 13, a band-pass filter 14, a demodulator 15 and a low-pass filter 16. The six-order continuous band-pass sigma-delta closed-loop control circuit for the MEMS gyroscope can eliminate influences of drive coupling signals on gyroscope detection signals, improve symmetry of two channels of fully-differential signals for detecting modality so as to eliminate asymmetric direct-current component, and further process outputted pulse width modulation digital signals b (t) to obtain and output simulation angular velocity signals omega (t).

The invention discloses a high-precision wide-range temperature measurement system. The high-precision wide-range temperature measurement system comprises a temperature sensor, a signal conditioning module, a channel switching selection module, a first-level differential amplification module, a second-level differential amplification module, an analog / digital conversion module, a signal acquisition and processing unit, an adjustable voltage reference module and a fixed voltage reference module. The change of multiple or single temperature sensor is subjected to signal conditioning and channel switching selection and is then differentiated and amplified with fixed voltage reference; the amplified signal is subtracted from the fed-back adjustable voltage reference and amplified, and is then converted into a digital value through a analog / digital converter; the signal acquisition and processing unit is used for carrying out feedback adjustment on the adjustable voltage reference according to the digital value and an algorithm to finish high-precision temperature measurement in a wide range. The high-precision wide-range temperature measurement system disclosed by the invention has the characteristics that the high-precision and wide-range temperature measurement can be finished by using a low-order-digit analog / digital converter, and the temperature measurement precision is improved in order of magnitudes on the basis of the low-order-digit analog / digital converter.