245 results about "Circuit noise" patented technology

An apparatus for reducing noise in fingerprint sensing circuits is disclosed in one embodiment of the invention as including a fingerprint sensing area onto which a user can apply a fingerprint. An analog front end is coupled to the fingerprint sensing area and is configured to generate an analog response signal. An analog-to-digital converter (ADC) samples the analog response signal and converts the sample to a digital value, which may be received by a digital device such as a processor or CPU. To reduce the amount of the noise that is present in the analog response signal and therefore reflected in the digital value, the digital device may be shut down while the ADC is sampling the analog response signal.

A system for detecting the level of the noise floor due to circuit noise as seen at the ADC for a wireless receiver. The system measures power after digitizing and filtering, and subtracts off any variable gain used in the analog front end to determine differentially the size of the signal at the antenna. The system further differentially detects the signal size of any incoming signal at the antenna in a similar fashion, and determines its size relative to the measured noise floor. If the level of the circuit noise of the receiver is known absolutely, the absolute signal size of the incoming signal can likewise be determined with this inventive method and system.

Techniques for preventing electrostatic discharge (ESD) and circuit noise are provided. More particularly, the present invention provides a method to prevent ESD damage during the assembly of computer disk commonly called a hard disk for memory applications. The coating mainly involves a ion-deposition process. Merely by way of example, the present invention is implemented by using filtered cathodic vacuum arc (FCVA) with a dissipative crystalline and / or amorphous carbon base thin film coating on a flexible circuit to drain the potential electrostatic charges during circuit assembly and interconnect processes, yet it would be recognized that the invention has a much broader range of applicability on any electronic apparatus that is susceptible to electrostatic damage and static noise.

The invention discloses a high-sensitivity magnetic measurement device in an environment field based on disturbance compensation and a realization method thereof. In the method, the low-frequency disturbance compensation in an environment magnetic field is realized by a second feedback branch and a second magnetic flux locking loop, wherein the second feedback branch is composed of a second integrator, a low-pass filter, a second feedback resistor and a feedback coil; and the second magnetic flux locking loop is formed based on the second feedback branch. A super-magnetic conduction sensor established based on the method can realize the high-pass response frequency characteristics for the environment field and the low-pass response frequency characteristics for the circuit noise at the same time, ensures the suppression of the influence of environment field disturbance on SQUID (superconducting quantum interference device) magnetic measurement without influencing the weak signal measurement, and avoids the overflow phenomenon. Based on the super-magnetic conduction sensor, the method is suitable for the application environment in which the frequency of the magnetic field signal tobe measured is higher than the disturbance frequency band (DC-30Hz) of the environment field.

This invention discloses one infrared detector structure and process method based on micro mechanic bridge resonance device, wherein the detector is composed of bridge resonance chip and cover board through vacuum sealing technique or gas sealing technique; the incidence infrared line is to micro mechanic bridge surface through infrared incidence window to lead the bridge temperature rise and to add axis stress force and to lower resonance frequency to reflect incidence infrared strength.

The invention relates to a low power consumption RF front-end circuit of the wireless receiver, belonging to the technical field of the integrated circuit of the RF wireless receiver, , comprising an RF input matching network, an amplifier stage, a bridge transformer, an LO switch stage, an IF load and a current source bias circuit; wherein, the RF input matching network implements the impedance matching between an antenna and the amplifier stage; the amplifier stage is used for amplifying the signal, the bridge transformer transfers the signal amplified to the LO switch stage and implements DC isolation between the front stage and back stage; the LO switch stage is used for implementing frequency mixing of the RF current signal and the LO signal and outputting alternatively the IF signalon an outputting differential load. Compared with the traditional RF front-end circuit, the circuit structure can use an on-chip integrated transformer or an on-chip inductor to implement inputting matching, and use the on-chip integrated transformer to implement the amplifying and downward frequency mixing of the RF signals perfectly, which simplifies the circuit structure. The circuit can be used in a low power supply voltage environment, and has the advantages of low DC power consumption, and less circuit noise and signal distortion.

The invention belongs to an RF wireless receiver integration circuit technical field, in particular to an orthogonal down-frequency mixer with low power loss and high performance. The invention consists of an RF conversion transformer, an LO switch class, an IF load class and a power supply bias; wherein, the RF conversion transformer amplifies and transmits the received RF current signals; the orthogonal LO switch class leads the RF current signals to be alternatively output on an output differential load by a LO frequency with the phase difference of 90 DEG, thus implementing that the RF frequency multiplied by the orthogonal LO frequency obtains the orthogonal IF signal which is then output on the load. Compared with traditional Kilbert frequency mixers, the circuit structure replaces the differential transistor of RF amplification class by an on-chip integration amplifier, which can lead the frequency mixer to be applicable to low power voltage and dramatically reduce circuit noise and signal distortion; two orthogonal LO switch classes are combined into one circuit, which leads the frequency mixer to output orthogonal IF signals, simplifies the design of the wireless receiver and obviously reduces the power loss of the frequency mixer module.

Noise occurring in a circuit is more accurately detected. A low-pass filter (11) is connected to a power supply line for a power supply terminal (VDD), and noise in the power supply line is removed to generate and output a referential voltage (V0). A high-pass filter (12) is connected to a power supply line, and a noise signal in the power supply line is passed with the referential voltage (V0) as a reference. A high-pass filter (13) is connected to a ground line for a ground terminal (GND), and a noise signal in the ground line is passed based on the referential voltage (V0) as a reference. A reference voltage generation circuit (14) generates and outputs a reference voltage (Vref) based on the referential voltage (V0) as a reference. Comparison circuits (CMP1 and CMP2) respectively compare output voltage of the high-pass filters (12 and 13) and the reference voltage (Vref). A noise determining circuit (15) changes the reference voltage (Vref) to obtain a comparison result at the same time for the comparison circuits (CMP1 and CMP2).

The invention discloses a micro-optical acceleration sensor integrated with grating piezoelectric modulation and a detection method of the micro-optical acceleration sensor. The micro-optical acceleration sensor comprises a shell; light sources and gratings are sequentially arranged in the shell along a light path; a base, an MEMS (Micro-electromechanical System) sensing mechanism and a piezoelectric ceramic part are also arranged in the shell along the light path, wherein the MEMS sensing mechanism is arranged between the base and the gratings and is arranged in the shell in a sliding manner, the piezoelectric ceramic part is arranged between the grating and the MEMS sensing mechanism, and one surface of the piezoelectric ceramic part is fixed on the gratings; the MEMS sensing mechanism comprises a mass block and a cantilever beam connected with the mass block; and one surface of the mass block facing the gratings is a reflecting surface plated with a metallic aluminium film. The micro-optical acceleration sensor has the advantages that as the piezoelectric ceramic part is introduced as a modulator, the detection sensitivity of the sensor can be greatly increased; and by detecting two diffraction light intensity signals with different orders and adopting phase locking amplification and differential treatment, the circuit noise is reduced, and the measurement accuracy of a system is increased.

The invention discloses a capacitance detection device used for fingerprint identification, comprising a detection screen, a conductor frame and a detection device. The detection screen comprises a plurality of detection units, and each detection unit comprises a first conductor layer, a second conductor layer, a third conductor layer, and a fourth conductor layer. The induction capacitance can be generated by the first conductor layer and a finger touching the detection screen. The feedback capacitance can be generated between the first conductor layer and the second conductor layer, and the integral capacitance can be generated between the third conductor layer and the fourth conductor layer. When the finger contacts the detection screen, the finger is electrically connected with the conductor frame. The detection device is used to charge the induction capacitance and the feedback capacitance in the sampling phase, and can be used to measure and control the transfer of the charges of the induction capacitance and the feedback capacitance to the integral capacitance in the integral phase, and at the same time, can be used to measure the voltage variable quantity of the integral capacitance in the integral phase, and can be used to calculate the induction capacitance according to the voltage variable quantity. The capacitance detection device is advantageous in that the fingerprint detection accuracy can be improved, and at the same time, the circuit noises can be effectively reduced, and the power consumption and the area of the circuit can be reduced. The invention also discloses a fingerprint identification device.

The invention discloses an electromagnetic type oil metal particle monitoring sensor resistant to environmental magnetic field interference. The electromagnetic type oil metal particle monitoring sensor comprises a metal particle sensing unit and a smart transmitter, wherein the metal particle sensing unit is used for inducing and producing induced voltage when metal particles pass by the sensor; and the smart transmitter is used for generating an excitation signal required by the metal particle sensing unit, sending the excitation signal to the metal particle sensing unit, receiving an induced voltage signal output by the metal particle sensing unit, eliminating interference of an external environment magnetic field and influences of an excitation magnetic field, obtaining a useful signal induced when the metal particles pass by the sensor, performing analog-digital conversion and processing on the signal, eliminating circuit noise, recognizing and counting the metal particles and uploading information to a network. According to the sensor, the disturbance resisting capacity and the recognition capability of tiny metal particles can be improved, and a high-performance monitor is provided for on-line monitoring of metal particles in lubricating oil.

A CMOS image sensor system includes first and second groups of CMOS sensors each responsive to periodic first and second clock signal edges, the second clock signal edge being out-of-phase with the first clock signal edge. Output signals of the first group of CMOS sensors are coupled to a first group of sampling capacitors, respectively, by a first group of sampling switches. Then output signals of the second group of CMOS sensors are coupled to a second group of sampling capacitors, respectively, by means of a second group of sampling switches. Sampled signals on the second group of sampling capacitors to an input of an ADC, and then sampled signals on the first group of sampling capacitors are coupled to the input of the ADC by means of by multiplexing and sample / hold circuitry. A phase of at least one of the first and second clock signal edges is adjusted in response to calibration information so as to avoid circuit noise from being superimposed on sampled signals coupled to the input of the ADC.

An apparatus and a method for testing semiconductor devices, such as individual integrated circuits in semiconductor chips, by directing a current in each circuit through a respective selected predetermined path to establish, in each circuit, a respective focused magnetic field and converting each such magnetic field into a respective voltage which, when fed to respective amplifier gated with a respective selected frequency, will modulate each such respective voltage. Each such respective voltage is then used to create a respective pulsating magnetic field that when detected by a respective remote magnetic sensor will provide a series of respective signals representative of the current in the respective circuit from which the pulsating magnetic field was derived. By applying each such series of voltages to a lock-in amplifier synchronized at the respective frequencies gating each respective amplifier the current in each circuit being tested can be accurately determined and will be free of errors due to circuit noise or crosstalk between the circuits under test.

On the surface of a semiconductor material of a first conductivity type 101a, a lateral MOS transistor 100 is described surrounded by a well 171 of the opposite conductivity type and, nested within the well, an electrical isolation region 102. The semiconductor region 101a embedding this transistor has a resistivity higher than the remainder of the semiconductor material 101 and further contains a buried layer 160 of the opposite conductivity type. This layer 160 extends laterally to the wells 171, thereby electrically isolating the near-surface portion of the semiconductor region from the remainder of the semiconductor material, and enabling the MOS transistor to operate as an electrically isolated high-voltage I / O transistor for circuit noise reduction, while having low drain junction capacitance.In the first embodiment of the invention (FIG. 1), the buried layer 171 extends vertically deeper from the surface than the electrical isolation region 102, thereby enabling a separate contact 106 to the electrically isolated near-surface portion 101a of the semiconductor region.

The invention provides a low-noise quick-start low-dropout linear regulator and belongs to the field of power management. The low-noise quick-start low-dropout linear regulator comprises a band-gap reference voltage source, a pre-adjustment module, a low-pass filter and an error amplifier, wherein the band-gap reference voltage source provides stable reference voltage for a pre-adjustment amplifier, the pre-adjustment module comprises the error amplifier and a resistive voltage-dividing network and is used for adjusting the band-gap reference voltage into voltage to be outputted, the low-pass filter is connected to filter out noise of a reference module and a feedback resistor, output voltage passing through the filter is inputted into the error amplifier, and output voltage not changing along with inputted power voltage and a load is provided according to a negative feedback principle. The low-noise quick-start low-dropout linear regulator has the advantages that the condition that a low-pass filter circuit has a low corner frequency can be guaranteed only with a small area, circuit start time cannot be affected, and the output voltage can be outputted with ultralow noise within a short start time, so that the chip area is greatly reduced and circuit noise performance is improved to a great extent.

The invention provides a tolerance analog circuit fault diagnosing method based on wavelet transform and fractal dimension, which comprises the following steps of: aiming at the problem of analog circuit error diagnosis brought by element tolerance, circuit noise and measurement error, carrying out noise elimination processing on a response signal of a circuit by using wavelet transform; aiming at the problem that a transverse shaft and a longitudinal shaft of a sampling signal of an analog circuit are two physical quantities, improving the accuracy of fault diagnosis by using a method for respectively uniformizing the transverse shaft and the longitudinal shaft; aiming at the problem of error diagnosis caused by characteristic overlapping which is probably generated by directly extracting a wavelet decomposed coefficient as the fault characteristic, calculating a box dimension as the fault characteristic by using a wavelet decomposed signal; and inputting the characteristics into a BP (Back Propagation) network for carrying out fault positioning, wherein the adjustment of BP network weight is realized in a batch processing way. By adopting the invention, the speed and accuracy of fault diagnosis can be improved.

The invention discloses a difference simulation front end device for a low-frequency signal detection and transmission system. The device comprises a magnetic sensing module, a low-pass filter module, a difference amplification module and at least one conversion comparison module, wherein the magnetic sensing module, the low-pass filter module, the difference amplification module and the conversion comparison module are sequentially connected. Each conversion comparison module comprises a digital-to-analog convertor and a first difference comparator, an output end of the difference amplification module is connected with a difference input end of the related first difference comparator, and a difference output end of each digital-to-analog convertor is connected with a difference reference electrical level input end of the related first difference comparator. By adopting the technical scheme, the interference on a low-frequency signal received in the low-frequency signal detection and transmission system from circuit noise and environment noise can be reduced, the capability of inhibition on a common-mode electrical level is improved, and thus the precision on detection and control of a low-frequency alternating magnetic field distance is improved.

The invention relates to a remote failure diagnosis system of an infrared shaft temperature detection station, comprising a main machine and a branch machine. The main machine and the branch machine are connected by a telephone network; the main machine comprises an embedded computer and an intelligent control card; the branch machine comprises an intelligent control card, a voice prompt circuit, a power supply detection circuit, a power cut-transmission control circuit, a battery charging circuit, a voltage measurement circuit and a noise measurement circuit; detection control signaling of the system adopts the dual-tone multifrequency transport protocol; a code error test circuit realizes the remote control test of channel code error rate on a solid loop communication interface; and pseudo-random sequence codes required by the code error test are realized by adopting software mode (linear congruence algorithm). When the infrared detection station has failures, the positions of failures (power supply, communication and detection station) can be rapidly judged by using the system, and simple failure treatments (reset, power cut and power supply) are performed, thereby eliminating week detection of the maintenance of the infrared shaft temperature detection system and providing a technical support means for realizing automatic monitoring and rapid failure treatment.

The present invention relates to one kind of automatic photoelectronic test instrument for the response time of LCD, and solves the technological problem of providing automatic photoelectronic test instrument for the response time of LCD with simple and accurate test and capable of eliminating circuit noise interference. The utomatic photoelectronic test instrument can measure the whole response time and grey scale response time of LCD, and consists of brightness detector to convert the brightness signal into electric signal; data acquisition board comprising monolithic computer, amplifier circuit, A / D converter circuit, data memory circuit and level converting circuit; computer to power the data acquisition board and to communicate with the data acquisition board via RS232 interface; and signal generator to generate video test signals of different grey scales. The present invention is used in testing LCD.

The invention provides a resonant mode optical gyroscope signal detection device and method based on a virtual instrument, belonging to the technical field of optical gyroscope signal detection. The resonant mode optical gyroscope signal detection device comprises a signal modulating module, a collection unit A, a collection unit B, an FPGA (Field Programmable Gate Array) control unit and a computer based on a PXIe (Pci Express-extensions-for-instrumentation) bus; an object to be detected is a photoelectric mixing module; and the photoelectric mixing module comprises a first detector, a second detector, an integrated optical phase modulator and a light source. According to the invention, modularized hardware of the virtual instrument is used for replacing a traditional detection circuit, hardware developing time is shortened, circuit noise is small, the anti-jamming capability is strong and the gyroscope precision is improved. Digital signal processing of a resonant mode optical gyroscope is carried out on FPGA programming based on labview virtual instrument software; and the verification of an algorithm can be rapidly carried out according to abundant resources in an FPGA and the flexibility of labview graphics programming, so as to accelerate a research speed of the resonant mode optical gyroscope.

The invention provides an extracting method for fixed star sensitive east and west parameters of stationary satellite imaging navigation and registration. The extracting method comprises the following steps of obtaining a changing curve of a total gray value of pixels of each line along with time; obtaining a moment that a fixed star image center crosses a center line of the pixels of the line; fitting a motion law of the fixed star image center in east and west line coordinates of a satellite remote sensing detector array; obtaining a moment that the fixed star image center crosses a center line of the east-west direction of the satellite remote sensing detector array. According to the extracting method provided by the invention, high-frequency error of star positions caused by factors such as optical imaging of the detector, circuit noises, high-frequency wobble of a satellite and the like can be eliminated by multiframe data information fusion processing and curve fitting, thereby improving the identification accuracy of fixed star position parameters. The extracting method can be used for stationary satellite imaging navigation and registration, and has important significance for improving on-orbit thermal deformation precision of a remote sensing imaging system and the imaging navigation and registration processing property by acquiring parameters such accurate time and the like that the fixed star crosses the center of the detector array.

The invention relates to a chopping stable instrument amplifier, comprising a low-gain high-frequency closed circuit, a high-gain low-frequency closed circuit, and a residual RRL (Ripple Reduction Loop); wherein the low-gain high-frequency closed circuit consists of an operational amplifier Gm3 and an operational amplifier Gm4; the high-gain low-frequency closed circuit consists of a chopper CH1,an operational amplifier Gm1, a chopper CH2, an operational amplifier Gm2, a switched capacitor notch filter NOTCH and the operational amplifier Gm4; and the residual RRL consists of induction capacitors C41 and C42, a cascode buffer Cascade Buffer 1, a chopper CH3, a cascade buffer Cascade Buffer 2, an integrating capacitor Cint, and an operational amplifier Gm5. The chopping stable instrument amplifier of the invention has the beneficial effects that: through the low-gain high-frequency closed circuit and the high-gain low-frequency closed circuit, offset voltage and 1 / f noise of a circuit can be effectively eliminated, and bandwidth of the circuit can be greatly raised, on that basis the RRL is introduced to effectively reduce the amplitude of the ripple output by the circuit, thus thewhole circuit noise is optimized, low-noise output is achieved, thereby improving circuit accuracy.

An Image sensing apparatus employing a multi-chip system and having a super-parallel circuit structure capable of performing processes such as image processing in real time. A first chip of a first of a first stage has first pixel circuits each having an optical sensor and first processing circuits and arranged in a matrix. A second chip of a second stage has second pixel circuits each having an analog memory for storing analog information from the preceding stage and second processing circuits and arranged in a matrix so as to correspond to the first pixel circuits. In each of the first and the second chip, each of the first and the second processing circuits receives an analog signal from another first and second processing circuit in the vicinity so as to perform first and second analog processing and performs circuit noise compensation by parallel calculation.

Noise removal and detection are performed for a signal VBUS in a detection portion in accordance with a low-frequency clock signal CLK generated by a CR oscillation circuit, and a detection signal VBD is received by a process control portion. A signal VBC detected by the detection portion is supplied to a quartz oscillation circuit as an operation-enable signal ENB. Thus, when a data transmission is designated by the signal VBUS, the quartz oscillation circuit supplies a high-frequency clock signal CK to a transmission function portion, enabling a data transmission. The operation-enable signal ENB is not supplied to the quartz oscillation circuit when data transmission is not performed. The power consumption of the CR oscillation circuit is small, so power consumption can be reduced.

The invention relates to the field of electronics and discloses a noise eliminating method and a noise eliminating circuit. The noise eliminating method comprises the following steps of sampling output voltage signals of a power-level circuit, and obtaining a current output feedback signal; and determining whether the frequency of a first driving signal currently input to the power-level circuit is in an audio range according to a current output feedback signal, if yes, disconnecting the power-level circuit and a circuit of the first driving signal, outputting a first low-frequency driving signal and a first high-frequency driving signal to the power-level circuit, wherein the frequency of the first low-frequency driving signal is lower than the lower limit of the audio, and the frequency of the first high-frequency driving signal is higher than the upper limit of the audio. The application of the technical scheme of the invention facilitates the reduction of the circuit noise and avoidance of the circuit loss.

The invention relates to an analog integrated circuit technology, in particular to a reference voltage source. The reference voltage source is characterized by comprising an input bias and starting circuit, a switch capacitive circuit and an operational amplifier and reference generating circuit. The input bias and starting circuit is connected with the switch capacitive circuit, and the switch capacitive circuit is connected with the operational amplifier and reference generating circuit. The reference voltage source has the advantages that the influences of transistor mismatch and resistance bias on the accuracy of the reference voltage are avoided, a switch capacitive technology is utilized, a reference voltage source circuit is completely composed of MOSFETs, large resistors and parasitic bipolar transistors are avoided, therefore, the accuracy of the reference voltage is improved, the layout area is decreased, circuit noise is reduced, the output reference voltage can be adjusted according to actual requirements, and the reference voltage source is suitable for the standard CMOS process. The reference voltage source is especially suitable for the fields of reference voltage sources.

The invention relates to a differential analog front end device used for a low frequency signal detection and transmission system, which is used in a short distance communication system. The differential analog front end device comprises at least one magnetic sensing module, at least one low-pass filter module, at least one amplifier, at least one digital / analog converter and at least one comparator, wherein the magnetic sensing module, the low-pass filter module and the amplifier are connected in sequence; the output end of the amplifier is connected with the forward input end of the comparator; the output end of the digital / analog converter is connected with the reverse input end of the comparator; and the amplifier is a differential amplifier. The differential analog front end device provided by the invention can reduce the interference of circuit noise and environment noise to low-frequency signal detection and a low-frequency signal received in a low-frequency signal, thereby improving the precision for detecting and controlling the high and low frequency alternating magnetic field distances.

Embodiments of the invention eliminate noise from burst signals by use of a reliable and simple method. In one embodiment, the read processor of the HDD has a noise elimination circuit. The noise elimination circuit retains multiple integral values of the waveform absolute values for each period in the burst signals read out from the head, then removes a maximum value and / or a minimum value from the multiple integral values, and transmits the remainder as noise-eliminated signal data. The noise elimination circuit is a circuit for eliminating noise from an N number of periods of burst signal data, and this circuit integrates the absolute values of the waveforms for each period in the N number of periods of burst signal data, compares the integral values of each period with one another, and outputs the remainder obtained by removing the maximum and minimum integral values, to the servo data decoder of the following stage.

The invention belongs to the field of power drive control, and provides an intelligent power module. An input circuit, a U-phase upper bridge arm output circuit, a V-phase upper bridge arm output circuit, a W-phase upper bridge arm output circuit, a U-phase lower bridge arm output circuit, a V-phase lower bridge arm output circuit and a W-phase lower bridge arm output circuit are adopted in the intelligent power module so that each IGBT tube is driven by an independent circuit, a jumper wire between the circuit and the gate electrode of the IGBT tube is effectively reduced, gate electrode inductance is reduced, circuit noise is reduced, and thus switching speed of the IGBT tubes is enhanced. Besides, switching time of the IGBT tubes of upper and lower bridge arms are maintained to be consistent without conduction at the same time so that safety of the intelligent power module is enhanced. Furthermore, the U-phase lower bridge arm output circuit, the V-phase lower bridge arm output circuit and the W-phase lower bridge arm output circuit are low-voltage area circuits so that technical manufacturing cost is relatively low, and thus manufacturing cost of the overall intelligent power module can be substantially reduced.