154results about How to "Reduce output noise" patented technology

In a transmitter of polar-loop architecture having a phase control loop and an amplitude control loop, as loop filters for controlling a loop band of the amplitude control loop, a first filter with lag-lead characteristics (secondary or more filter including a capacitor and a resistor) and a second filter of a perfect integrator type (filter including only a capacitor) are employed, and current-output type circuits are connected to respective front stages of the first and second filters.

The invention relates to a hemispherical resonance micro mechanical gyroscope. The hemispherical resonance micro mechanical gyroscope comprises a resonance layer, wherein the resonance layer comprises a hemispherical shell which has a concave inner surface and an outer surface opposite to the inner surface, the peak of the hemispherical shell is an anchor point, a plurality of silicon spherical surface electrodes are arranged around the hemispherical shell, the silicon spherical surface electrodes comprise drive electrodes, force balance electrodes, signal detection electrodes and shield electrodes, the drive electrodes, the force balance electrodes and the signal detection electrodes are separated by the shield electrodes, the hemispherical shell and the plurality of silicon spherical surface electrodes surrounding the hemispherical shell form a plurality of capacitors, and the resonance layer is made of polycrystalline silicon or silicon dioxide or silicon nitride or diamond. The hemispherical resonance micro mechanical gyroscope adopts the technology based on silicon micro machining, has small size and low production cost, has batch production capacity and has the sensitivity not depending on the amplitude, has low drive voltage, can greatly lower the output noise, and has higher accuracy compared with the existing gyroscope.

A micromechanical rotation rate sensor has a seismic mass and driving devices which cause a driving vibration of the seismic mass in a first direction x. The rotation rate sensor has measuring devices which measure a deflection of the seismic mass in a second direction y, and generate a deflection signal. The deflection includes a measurement deflection caused by a Coriolis force and an interference deflection, the interference deflection being phase-shifted with respect to the measurement deflection by 90°. Compensation devices are provided at the seismic mass to reduce the interference deflection. Regulation devices are provided, to which the deflection signal is supplied as an input variable, which demodulate an interference deflection signal from the deflection signal, and which generate a compensation signal from the interference deflection signal, which is supplied to the compensation devices.

The invention relates to an alternating current/direct current sensor. The alternating current/direct current sensor comprises a high-permeability transformer unit, an excitation signal generation unit, a direct current signal detection unit, a restoring circuit unit, an alternating current signal processing unit and a power amplification unit. The high-permeability transformer unit comprises a first magnetic core, a second magnetic core, a first magnet exciting coil, a second magnet exciting coil, a third magnetic core, a primary coil, a secondary coil and an auxiliary coil, wherein the first magnetic core and the second magnetic core are independent of each other; the first magnet exciting coil and the second magnet exciting coil are wound around the first magnetic core and the second magnetic core respectively; the third magnetic core, the first magnetic core and the second magnetic core are overlapped so as to form an integrated magnetic core; the primary coil, the secondary coil and the auxiliary coil are wound around the integrated magnetic core. The performance of the alternating current/direct current sensor is improved remarkably. The alternating current/direct current sensor has the advantages of being low in power dissipation, high in magnetic disturbance resistance capacity, simple in structure, light, high in response speed, high in flexibility, good in interchangeability, convenient to install, calibrate, adjust and maintain, and the like.

The invention relates to the field of CMOS (Complementary Metal Oxide Semiconductor) image sensors and provides a digital pixel sensor which can realize correlated double sampling and has a wide dynamic range. The technical scheme adopted by the invention is that a correlated double sampling method of a wide-dynamic-range digital pixel sensor divides total pixel exposure time into two stages; at a reset sampling stage, the reference voltage Vref of an in-pixel comparator is enabled to be higher voltage, and the voltage of a photodiode drops from reset voltage and is intersected with the reference voltage Vref for a second time at the reset sampling stage to obtain a reset sampling value; at an integral sampling stage, the reference voltage Vref becomes lower voltage, and the voltage of the photodiode continuously drops and finally is intersected with the reference voltage Vref for a second time at the integral sampling stage to obtain an integral sampling value; and difference between the integral sampling value and the reset sampling value is the final signal value. The correlated double sampling method of the wide-dynamic-range digital pixel sensor is mainly applied to the design of CMOS image sensors.

The invention discloses a method and system for DVB-T2 channel estimation. The method comprises the steps that filters are sequentially selected from a filter bank in a self-adaptive mode according to the relation between signal delay and frequency domain response of the signal delay and interpolation filtering in the frequency domain direction is achieved on a base band in a grouping mode, so that influence caused by noise on the system is effectively reduced and meanwhile, hardware achievement cost and power consumption are reduced. According to the method, influence caused by the noise on the DVB-T2 system is effectively reduced and the channel estimation accuracy is improved.

An image sensor having readout noise reduction mechanisms is disclosed. The image sensor can include a first sampling transistor, a second sampling transistor connected to the first sampling transistor, an averaging transistor electrically connecting the first and second sampling transistors in series, a reset sampling transistor connected to the first and second sampling transistors, and a differential device connected to the reset sampling transistor and the first and/or second sampling transistors.

The invention discloses a PWM method for an electric vehicle motor inverter. The method comprises the steps of performing PWM on the inverter by an NZPWM method, and reasonably arranging a reference voltage vector synthesis sequence and a PWM pulse action mode of each section; correcting a three-phase modulation wave generated by NZPWM to obtain an inverter boundary modulation ratio parameter, andrespectively executing NZPWM and SVPWM according to the modulation ratio parameter; performing over-modulation on the inverter by a discrete PWM method after a voltage vector enters an over-modulation region from a linear modulation region, dividing the over-modulation region into two regions, and setting a modulation ratio of lower boundaries of the two regions; and executing discrete PWM of thetwo over-modulation regions according to the modulation ratio to obtain an expected PWM waveform. By the method, the common-mode voltage output amplitude at zero vector is effectively reduced, motorshaft current amplitude is suppressed, the service lifetime of a motor bearing is prolonged, the vibration and the noise output of a motor inversion system are reduced, and the driving quality of thewhole vehicle is improved.

A chopper stabilized amplifier with synchronous switched capacitor noise filtering is disclosed. In an exemplary embodiment, an apparatus includes a chopper amplifier having an input that receives an input signal and an output that outputs an amplified signal. The chopper amplifier includes an input chopping circuit and an output chopping circuit, where the input and output chopping circuits operate in response to a chop clock. The apparatus also includes a switched capacitor filter having an input that receives the amplified signal and an output that outputs a filtered signal. The switched capacitor filter operates in response to a filter clock. The apparatus also includes a filter timing adjuster that receives a reference voltage and adjusts a phase of the filter clock with respect to the chop clock to reduce chopper noise on that reference voltage.

The invention discloses an X-waveband power amplifier based on GaN. The X-waveband power amplifier comprises MIN capacitors, a filter capacitor, a thin-film resistor, a stable resistor, a spiral inductor, a microstrip transmission line, a T-shaped connector and a GaN-based HEMT. A signal input end (RFIN) is connected with an input end (1) of the GaN-based HEMT (H) through the first MIN capacitor (C1), the microstrip transmission line (W) and the T-shaped connector (T). A drain electrode control end (Vds) is connected with an output end (2) of the GaN-based HEMT through the microstrip transmission line (W) and the T-shaped connector (T). The microstrip transmission line (W) is a 100-micrometer high-impedance microstrip transmission line. A 100-microfarad electrolytic capacitor is selected as the filter capacitor. The GaN-based HEMT (H) is an NRF01-02a HEMT tube core. The thin-film resistor is made of NiCr material. The X-waveband power amplifier is matched with the input end in a conjugate mode through a load traction method so as to solve the problem that negative resistance occurs at the port of the transistor; the X-waveband power amplifier is stable in work, has the bandwidth of 3.6 GHz to 8.0 GHz, the maximum gain of 11.04 dB, the maximum output power of 33 dBm and the maximum PAE of 29.2%, and is small in voltage standing wave ratio.

The invention discloses a harmonic control CMOS frequency mixer based on a transformer structure. The frequency mixer comprises a trans-conductance level, a harmonic-controlled transformer network, a switch level and an output level; the trans-conductance level converts an input radio frequency into the radio frequency current, since the transistor is non-linear, the converted radio frequency current contains the fundamental wave and each sub-harmonic component, the radio frequency current is injected into the switch level after the transformer harmonic control network inhibits the second harmonic generation and filters the third harmonic therein; and finally the output level outputs an intermediate frequency signal through the modulation and frequency-mixing of the switch level. The harmonic control network based on the transformer structure is imported between the trans-conductance level and the switch level of the frequency mixer, wherein the harmonic control network has the features of improving the linearity, the isolation degree and the noise performance of the frequency mixer, and reducing the working voltage and the static power consumption.

A device used to convert digital signal into analog signal comprises an operation amplifier, a first capacitor set, a second capacity, set, a first switch set and a second switch set. In the first time period, reference voltages corresponded by multiple bit in digital signal are transmitted respectively to the first capacity set; in the second time period, the second capacity set is connected to the first capacity set as the first switch set is closed and in the third time period, the second capacity set is connected between input end and output end of the operation amplifier as the second switch set is closed.

A CPP thin-film magnetic head includes a bottom shield layer; a top shield layer, the bottom shield layer and the top shield layer being disposed at a predetermined interval; a thin-film magnetic head element between the bottom shield layer and the top shield layer; an insulating layer behind the thin-film magnetic head element in the height direction and disposed between the bottom shield layer and the top shield layer; and a metal layer in the insulating layer, the top shield layer including a first top shield sublayer on the thin-film magnetic head element; and a second top shield sublayer behind the first top shield sublayer in the height direction, the second top shield sublayer and the bottom shield layer being conductively connected through the metal layer, wherein a current flows in the direction orthogonal to a surface of a layer constituting the thin-film magnetic head element.

The invention provides a balance optical microwave regeneration system which comprises a phase discrimination module and a radio frequency (RF) processing module, wherein the phase discrimination module and the RF processing module are sequentially connected with a peripheral signal source used for providing a laser pulse signal; the phase discrimination module comprises an opto-isolator, a Sagnac fiber-optic ring and a balance detector which are sequentially connected; the Sagnac fiber-optic ring comprises a 3*3 optical fiber coupler and a phase modulator; a first input end of the 3*3 optical fiber coupler is connected with the opto-isolator, a second input end of the 3*3 optical fiber coupler is connected with a first optical input port of the balance detector, a third input end of the 3*3 optical fiber coupler is connected with a second optical input port of the balance detector, a second output end of the 3*3 optical fiber coupler is connected with a first optical interface of the phase modulator, and a third output end of the 3*3 optical fiber coupler is connected with a second optical interface of the phase modulator. The balance optical microwave regeneration system is simple in structure, low in noise, high in stability, high in jitter accuracy, low in cost and convenient to operate.

Provided is a magnetic absolute rotary encoder, comprising a rotation shaft, multiple rotating wheels that can rotate along the rotation shaft, multiple encoding units that correspond to the multiple rotating wheels one-to-one, and one or more permanent magnet assemblies that provide the magnetic bias to the multiple encoding units. Each encoding unit comprises a magnetically permeable encoder disc, the structure thereof enabling the magnetic permeability thereof to be different according to the different positions of the rotation shaft, and comprises multiple sensor units that comprise multiple magnetic sensors. The sensor units are used to sense the magnetic permeability of the magnetically permeable encoder disc and to output the sensor signals that characterize the relative position of the magnetically permeable encoder disc. According to the sensor signals of the sensor units, each encoding unit outputs the value that characterizes the selected rotation position of the corresponding rotation wheel, thereby enabling an absolute magnetic rotating encoder that is simple and low in cost and has more precise magnetic encoder discs.

The invention discloses a noise suppression method for a voice application system of a front-end device. The noise suppression method is applied to the front-end device connected to a sound output device and comprises the steps that: a sound input device collects ambient sound, the front-end device obtains the sound strength of the ambient sound according to the collected ambient sound as an ambient noise threshold and store the same; the sound strength of real-time input sound is compared with that of the ambient noise threshold; when the input sound strength is smaller than the ambient noise threshold and the duration reaches a preset duration, the connection with the sound output device is disconnected; and when the input sound strength is larger than the ambient noise threshold, the connection with the sound output device is connected. The invention further discloses an apparatus and a system corresponding to the method, the entire voice opening and closing process of the noise suppression method disclosed by the invention is automatically controlled by IPC without user intervention; and a sound box can have good antijamming capability in various external environments, and inputs no noise in a standby state.

The invention discloses a noise separation method based on an optical transmission-reception system of a fiber sensor, comprising steps of designing a magnetic shielding device, determining a circuit noise RMS value acquisition method, measuring and adopting the RMS value acquisition method to obtain terminal output overall noise of the optical transmission-reception system of the fiber sensor and a local noise RMS value of a sub-module, determining a noise conversion parameter and separating light source intensity noise N0, and calculating the noise proportion of each module in the overall noise of the optical transmission-reception system of the fiber sensor. When measuring the overall noise, the noise separation method based on the optical transmission-reception system of the fiber sensor can obtain the light source intensity noise of the light source and the noise value of all circuit modules, and can obtain the proportion in the overall noise of the optical transmission-reception system of the fiber sensor.

The invention discloses a low-noise voltage-controlled oscillator biasing circuit and a frequency source self-calibration method. A voltage division circuit comprises a resistor R1, a first bipolar junction transistor BJT1 and a second bipolar junction transistor BJT2 which are connected in series in sequence, wherein the R1 is connected with the collector of the BJT1; the emitter of the BJT1 is connected with the collector of the BJT2; the collector of the BJT1 is connected with the base of the BJT1; and the collector of the BJT2 is connected with the base of the BJT2. In a self-calibration state, voltage output by the biasing circuit is connected with the tuning voltage input end and the power supply end of an LC voltage-controlled oscillator respectively. The output noise of the biasing circuit disclosed by the invention is low, a filter capacitor does not need to be added externally, the pins of a chip can be effectively reduced, and the cost is reduced; and when a frequency source is in the self-calibration state, the voltage output by the biasing circuit is connected with the tuning voltage input end and the power supply end of the LC voltage-controlled oscillator respectively, so that influences caused by the change of an output DC (Direct-Current) point due to changes of the resistor and the BJTs in a whole temperature range can be effectively eliminated, and change of the frequency source along with temperature change in the self-calibration state is avoided.