141results about How to "Eliminate common mode noise" patented technology

A communication system is provided which allows video and audio / video transmissions over unloaded, twisted pairs of telephone wires. The system provides for automatic compensation of attenuation of a broadband video signal by measuring the attenuation of the low frequency components of the signal to determine the length of the unloaded, twisted pair through which the signal has been transmitted. This calculation is performed by comparing the attunated signal with the known signal level of transmission. Based upon the calculated length, the signal is amplified nonlinearly, since a greater loss occurs in the high frequency portions of a broadband signal than in the low frequency portions in transmission over twisted pairs of telephone wires. The signal is thereupon reconstructed. Also, the system allows transmission of a broadband frequency spectrum much wider than has heretofore been obtained. A broadband signal of at least 10.7 MHz can be transmitted over the system. The system also provides for left and right audio inputs and outputs, as well as auxiliary inputs and outputs. The transmission system can be utilized so that persons with a video camera and a personal computer can communicate with each other, transmitting full-motion, color video over unloaded, twisted pairs of telephone wires.

A double reference wave modulation scheme for filterless power amplifiers is disclosed for reducing EMI and common mode voltages. In the filterless power amplifier, differential outputs for driving load impedance are feedback and corrected based on input audio signals. Reference wave generators generate reference waves. A control logic results pulses in the pair of differential outputs in response to a clock signal or a reference voltage and a cross relationship between the input audio signal and the first and second reference waves. Pulses of one of the differential outputs are not overlapped with pulses of the other of the differential outputs for eliminating common mode noises of the power amplifier.

A double reference wave modulation scheme for filterless power amplifiers is disclosed for reducing EMI and common mode voltages. In the filterless power amplifier, differential outputs for driving load impedance are feedback and corrected based on input audio signals. Reference wave generators generate reference waves. A control logic results pulses in the pair of differential outputs in response to a clock signal or a reference voltage and a cross relationship between the input audio signal and the first and second reference waves. Pulses of one of the differential outputs are not overlapped with pulses of the other of the differential outputs for eliminating common mode noises of the power amplifier.

The invention relates to a capacitive micro-accelerometer which adopts the design of a bulk-silicon processed micro-mechanical structure and the design of an integrated circuit, which pertains to the field of MEMS micro-inertial instruments. The capacitive micro-accelerometer adopts two chips of a micro-mechanical sensor and a signal processing circuit for respective integration, the capacitive micro-accelerometer is carried out by the overall packaging and finally realizes an internal structure of the packaged system; the micro-mechanical sensor of the invention adopts a full-differential micro-mechanical structure sensitive element to be matched with a follow-up circuit; the signal processing circuit comprises a full-differential switched capacitor charge amplifier front-end circuit module with adjustable gain, a back-end cascade circuit module which is composed of a first-order switched capacitor low-pass filter and an instrument amplifier and an auxiliary circuit module which is composed of a reference voltage and bias current generating circuit, a self-test circuit and a clock generating circuit. The two-chip proposal of the system of the invention carries out the respective integration and overall packaging, thus simplifying the complexity of the system, reducing the processing cost and the difficulty and improving the performance and the yield.

The invention discloses a universal detection chip system for weak signals of a sensor. The chip system comprises a detection subsystem and an auxiliary subsystem which are both connected with the sensor, wherein the detection subsystem comprises two current detection channels and a voltage detection channel; the current detection channels realize detection to weak current signals input by the sensor through current and voltage conversion, voltage amplification and analog-digital conversion; the voltage detection channel first converts weak voltage signals input by the sensor into current signals and then outputs the current signals to the current detection channels, thereby indirectly realizing the detection of weak voltage signals; the auxiliary subsystem is used for providing required bias current, voltage, a clock and control signals for the sensor and the detection subsystem. The chip system has the characteristics of low noise, low power consumption, high precision, high integration level and the like, can be integrated on a substrate together with the sensor to form a lab-on-chip.

The invention is about a capacitor sensing circuit having anti-electromagnetic interference capability, wherein a filter is coupled to a capacitor to be detected and receives a plurality of reference signals to generate a first filter signal and a second filter signal, a difference circuit receives the first filter signal and the second filter signal and eliminates a common-mode noise of the first filter signal and the second filter signal to generate a difference signal, and the size of the signal is related to the size of the capacitor to be detected to achieve the aim of detecting the capacitor to be detected. The difference circuit eliminates the common-mode noise to achieve the anti-electromagnetic interference capability, and the difference circuit can regulate the output of the filter within a dynamic range, thus the capacitor sensing circuit has characteristic of low consumption of frequency cycles number.

In a common-mode choke coil, first annular conductors are helically defined from the lower layer to the upper layer, and first annular conductors are helically defined from the upper layer to the lower layer. Further, second annular conductors are helically defined from the lower layer to the upper layer, and second annular conductors are helically defined from the upper layer to the lower layer. The first annular conductors and the second annular conductors are disposed alternately in a lamination direction. The first annular conductors and the second annular conductors are disposed such that substantial portions of the annular conductors adjacent to each other in the layer direction do not overlap in a planar view. This structure achieves a compact common-mode choke coil with which the loss of normal-mode signals is small, and which is highly capable of removing common-mode noise.

The invention relates to an absolute optical code wheel as well as an absolute coder and a method for detecting the absolute position thereof. The absolute coder comprises the absolute optical code wheel, and the absolute optical code wheel comprises a main raster unit and two auxiliary raster units; the two auxiliary raster units are respectively positioned at two sides of the main raster unit, and the raster numbers of the two auxiliary raster units are one less than that of the main raster unit. When the absolute coder is used for detecting the absolute position, the absolute optical code wheel can be rotated so as to find out optical detection signal zero points of the auxiliary raster units and also numerical values corresponding to the zero points of the main raster unit, thereby the absolute position can be derived. As the absolute coder can provide the calculation of an increment position and the absolute position simultaneously, the using elasticity can be increased.

The present invention relates to a capacitance sensing circuit with anti-EMI capability. A filter is coupled to a capacitor under test; receives a plurality of reference signals; and produces a first filter signal and a second filter signal. A difference circuit receives the first and second filter signals; eliminates the common-mode noise in the first and second filter signals; and produces a difference signal. The amplitude of the difference signal is related to the capacitance value of the capacitor under test. Thereby, the purpose of sensing capacitance can be achieved. In addition, by eliminating common-mode noise using the difference circuit, the anti-EMI capability can be achieved. Because the difference circuit can adjust the dynamic range of the output of the filter, the capacitance sensing circuit with anti-EMI capability can achieve capacitance sensing in few clock cycles.

A flexible circuit board comprises a signal layer, a grounding layer. A layer of insulating medium is filled between the signal layer and grounding layer; the signal layer is provided with a differential pairs comprising two differential transmission lines; a scooping area on the grounding layer is perpendicular and opposite to the differential transmission line; two grounding conductive material strips spaced from their adjacent transmission line are separately parallel at two sides of differential pair. The inventive flexible circuit board can transmits high speed signal, eliminates common mode noise problem derived from grid grounding layer of existing technology; The inventive flexible circuit board is accomplished without extra cost but regulating existing wire laying mode.

The invention discloses a displacement, force generation and measurement system and an indentation, scratch and surface profile meter. The system measures micro-newton level force and nanometer level displacement based on piezoelectric ceramics generated nanometer level displacement and bi / single pole capacitance difference structures, and comprises a piezoelectric ceramic displacement driver, a displacement sensor, a normal force sensor and a probe, wherein the sensors all employs bi / single pole capacitance difference structures, of which the capacitor arranging direction is along the setting direction, the piezoelectric ceramic displacement driver is so arranged to output displacement amount of the corresponding displacement driving signals along the setting direction and transmits the displacement amount to a target member of the displacement sensor, the displacement sensor is so arranged to transmit the displacement amount to the normal force sensor, and the probe is fixedly connected with the target member of the normal force sensor along the setting direction. The displacement, force generation and measurement system and the indentation, scratch and surface profile meter employing the displacement, force generation and measurement system have the advantages of good dynamic performance, high measuring sensitivity, easy manufacture and low cost.

A first transmission line for transmitting a first signal and a second transmission line for transmitting a second signal, which has the reverse phase of the first signal, are connected in series with a common mode choke coil. A third transmission line and fourth transmission line are each connected in series with the common mode choke coil, and transmit the first and second signals. A semiconductor device is connected in series with the third and fourth transmission lines, so as to transmit and receive the first and second signals. One end of a first terminator is connected in parallel with the first transmission line, and the other end is connected to the common mode choke coil. One end of a second terminator is connected in parallel with the second transmission line, and the other end is connected to the common mode choke coil. The noise eliminating capability of the common mode choke coil is increased by means of this structure.

Coherent optical signal processing is performed in a coherent receiver (or diagnostic / testing apparatus) that converts an amplitude and / or angle-modulated optical signal into two electrical signals. A simple receiver can only detect one phase of the signal and only the polarization that is aligned with a local oscillator laser polarization. To detect both phases and both polarizations, two sets of two interferometers, one each with a π / 2 phase shift are required. Coherent optical signal processing methods, apparatus, techniques, etc. are disclosed that include individual components comprising a polarization combiner, a Savart device and photodetection apparatus with substantially reduced temperature and alignment sensitivity operating in optical communication systems and / or subsystems. The various embodiments can be used alone or in such combinations to provide improved coherent optical signal processing in a receiver.

A digital data transmission apparatus includes a transmitting end (100) that includes: a binary / quadrary conversion unit (110) for converting a data stream; a coding unit (120) for mapping converted data to be coded; a digital filter (130); a D / A conversion unit (140); a low-pass filter (150) for attenuating noises which are caused by folding distortion; a differential driver (160); low-pass filters (170a) and (170b) for eliminating noises from differentially outputted signals; and a common mode choke coil (180) for eliminating common mode noises and outputting a resultant signal to a twisted pair cable (300), and a receiving end (200) that includes: a low-pass filter (210) for eliminating noises from the twisted pair cable; a receiver (220); an A / D conversion unit (230); a digital filter (240); an evaluation unit (250) for evaluating a signal level of a received signal; a decoding unit (260) for decoding the signal level into received data; and a synchronization unit (270) for generating a clock.

There is provided a bridgeless power factor correction circuit that corrects a power factor by complementarily switching two switches according to phase of input power without using rectifier bridge diodes. A bridgeless power factor correction circuit according to an aspect of the invention may include: a switching unit having a plurality of switches and alternately switching input AC power; a stabilizing unit rectifying and smoothing the power switched by the switching unit; and a control unit controlling an alternate switching operation between the plurality of switches according to phases of the input power.

A multilayer capacitor array 1 comprises a capacitor element body 2 having first, second, third, and fourth inner electrodes 13 to 16, and first to fourth terminal electrodes 3 to 6 disposed on the outer surface of the capacitor element body 2 and respectively connected to the inner electrodes 13 to 16. The first and second inner electrodes 13, 14 form a first capacitor section C1, while the third and fourth inner electrodes 15, 16 form a second capacitor section C2. The multilayer capacitor array 1 is mounted to a circuit board such that the first and third terminal electrodes 3, 5 are connected to first leads 22, 23, while the second and fourth terminal electrodes 4, 6 are connected to a second lead 24.

A power amplifier with noise shaping function is provided. The power amplifier includes a differential mode integrator, an integration and adjustment unit and a switch unit. The differential mode integrator is used for receiving a differential mode input signal and a differential mode output signal, and outputting a differential mode first signal. The integration and adjustment unit is coupled to the differential mode integrator for receiving the first signal and an output signal and outputting a single-end mode second signal. The switch unit is used for receiving the second signal and outputting the differential mode output signal to drive the load. The present invention uses a common mode input signal instead of the single-end input signal to eliminate the common mode noise, and uses a 2nd-order (or more than that) integrating circuit instead of the conventional filter to achieve a preferred effect of reducing the off band noise.

A transformer includes a magnetic element, a first winding, a second winding and a shield. The first winding is wound outside the magnetic element, the second winding is wound outside the first winding, and the shield is disposed between the first winding and the second winding.

A first to a fourth sampling switch (1a to 1d), a first to a fourth sampling capacitor (4 to 7), and a first and a second charge redistribution switch (2a, 2b) are provided on the input side of a differential amplifier (8). A first and a second reset switch (3a, 3b) are provided between the input and the output of the differential amplifier (8). An input signal voltage (Vinp) having a positive polarity, a comparison reference voltage (Vrefn) having a negative polarity, a comparison reference voltage (Vrefp) having a positive polarity, and an input signal voltage (Vinn) having a negative polarity are respectively applied through a first to a fourth sampling switch (1a to 1d) to one end of each of the first to the fourth sampling capacitor (4 to 7). During a reset period, the reset of the differential amplifier (8) is released after sampling of each voltage is completed, and during a comparison period, the first and the second charge redistribution switch (2a, 2b) are electrically connected.

A flexible printed circuit board comprises at least a signal layer, wherein two grounding layers are respectively arranged above and below the signal layer; two insulation dielectric layers are respectively arranged between the signal layer and the adjacent grounding layers; a differential pair is distributed on the signal layer and comprises two differential transmission lines; the two insulation dielectric layers have different relative dielectric constants; the portions on the grounding layers, which are vertical and opposite to the differential pair, are hollow areas; first horizontal spacing and second horizontal spacing respectively exist between the two edges of the hollow areas on the two grounding layers and the adjacent differential transmission lines and are not equal to each other. Without increasing extra cost, the flexible printed circuit board can be realized only by adjusting the existing wiring way.

Systems and methods are provided for differential sensing (DS), difference-differential sensing (DDS), correlated double sampling (CDS), and / or programmable capacitor matching to reduce display panel sensing noise. An electronic device may include one or more processors and an electronic display. The one or more processors may generate image data and adjust the image data based at least in part on display sensing feedback. The electronic display may employ sensing circuitry that obtains the display sensing feedback at least in part by applying test data to a pixel of a column of an active area of the display and differentially senses an electrical value of the pixel in comparison to a reference signal from a different column. This reference signal may provide a common mode noise reference, which is removed by the differential sensing and thereby enhances a quality of the sensed electrical value of the pixel.

A multi-band receiver is disclosed. The multi-band receiver includes a low-noise amplifier (LNA) and a mixer. The LNA includes a switched receiving circuit, a loading circuit, and a switching circuit. The switched receiving circuit has a first receiving circuit for receiving a first signal corresponding to a first frequency, and a second receiving circuit for receiving a second signal corresponding to a second frequency. The loading circuit is utilized for providing a specific load to the switched receiving circuit. The switching circuit is used for controlling whether the first signal or the second signal is transferred to the loading circuit. The mixer is coupled to the low-noise amplifier for receiving an output signal generated from the LNA and for down-converting the output signal.

The invention discloses a weak-reflection Bragg grating accelerometer and a sensing method thereof. First, second and third gratings which are distributed at equal intervals are graved in a polarization-maintaining sensing optical fiber; two pulses which are mutually independent in a time domain return after sequentially going through the first, second and third gratings to generate two interference pulses carrying outside vibration information, phase of the interference pulses carrying the outside vibration information is demodulated and then reduced so as to acquire outside vibration information inhibiting common-mode noise, and phase difference is proportional to outside vibration signals. Noise suppression level is elevated, common-mode noise introduced by a laser device and an acoustic optical modulator can be eliminated, environment noise introduced to the accelerometer itself by perturbation of outside environment can be eliminated, phase sensitivity is improved, transverse crosstalk is inhibited, cost of a sensing system is saved while size of the same is reduced, and this advantage is obviously demonstrated especially in a quasi-distributed multi-motif sensing network.

The invention relates to a flexible circuit board, which comprises at least one signal layer; a ground plane is respectively arranged above and below the signal layer; a layer of insulating medium is filled between the signal layer and the insulating layer; the signal layer is laid with a differential pair which comprises two differential transmission lines; the part of each ground plane which is perpendicular and opposite to the differential pair is a hollow area; both edges of the hollow area on each ground plane respectively have a first horizontal spacing with the adjacent differential transmission line thereof. The flexible circuit board can transmit high speed signals and eliminate the common mode noise derived from a gridding ground plane in the prior art. The flexible circuit board does not need to add additional cost and only needs to adjust the existing wiring mode.

The embodiment of the invention provides a display panel, a display device and a control method of the display device, relates to the technical field of display, and can solve the problem that acquired compensation parameters of a driving transistor are inaccurate. In the display panel, at least part of the pixel driving circuit further comprises a detection transistor; the grid electrode of the detection transistor is connected with the second scanning end, the first electrode of the detection transistor is connected with the first electrode of the driving transistor, and the second electrodeof the detection transistor is connected with the detection signal line; the display panel further comprises a detection reference signal line parallel to the detection signal line. An analog-to-digital conversion sub-circuit in the source drive circuit is configured to obtain a first digital signal according to a difference value of voltages input by two input ends and output the first digital signal to the time sequence control circuit, wherein the first digital signal corresponds to a compensation parameter of the driving transistor; the time sequence control circuit is configured to acquire compensation pixel data of the sub-pixel according to the first digital signal and the initial pixel data corresponding to the same sub-pixel.

The common mode filter of the instant disclosure includes a non-magnetic insulating substrate, a stacked-layer structure, an insulating layer, and a magnetic layer. The stacked-layer structure is arranged on the non-magnetic insulating substrate. The magnetic layer is covered on the stacked-layer structure by the insulating layer arranged therebetween. The stacked-layer structure comprises a first coil and second coil, wherein the first coil is coupled to the second coil to suppress the common mode noise. Specially, a width W (mm) and a length L (mm) of at least one coil in the first and second coils satisfy the relational expression of:[(14.1−fc) / 6.5]2<L / W<[(16.7−fc) / 4.5]2 Where fc (MHz) is the cutoff frequency of a differential-mode signal.

A multi-band receiver is disclosed. The multi-band receiver includes a low-noise amplifier (LNA) and a mixer. The LNA includes a switched receiving circuit, a loading circuit, and a switching circuit. The switched receiving circuit has a first receiving circuit for receiving a first signal corresponding to a first frequency, and a second receiving circuit for receiving a second signal corresponding to a second frequency. The loading circuit is utilized for providing a specific load to the switched receiving circuit. The switching circuit is used for controlling whether the first signal or the second signal is transferred to the loading circuit. The mixer is coupled to the low-noise amplifier for receiving an output signal generated from the LNA and for down-converting the output signal.

A power amplifier with noise shaping function is provided. The power amplifier includes a differential mode integrator, an integration and adjustment unit and a switch unit. The differential mode integrator is used for receiving a differential mode input signal and a differential mode output signal, and outputting a differential mode first signal. The integration and adjustment unit is coupled to the differential mode integrator for receiving the first signal and an output signal and outputting a single-end mode second signal. The switch unit is used for receiving the second signal and outputting the differential mode output signal to drive the load. The present invention uses a common mode input signal instead of the single-end input signal to eliminate the common mode noise, and uses a 2nd-order (or more than that) integrating circuit instead of the conventional filter to achieve a preferred effect of reducing the off band noise.

The invention discloses a high-speed fully-differential noise reduction device for CMOS optical receivers. The noise reduction device comprises a low-noise trans-impedance amplifier which is used for converting a current signal output by a photoelectric detector into a voltage signal and preliminarily amplifying the voltage signal and has low equivalent input noise current, a single-ended to differential circuit which is used for realizing conversion from single-ended to differential output, increasing the circuit bandwidth, amplifying the voltage signal, effectively reducing equivalent input noise current introduced by a back-end circuit and eliminating common-mode noise introduced by a power supply and the like, a two-stage three-order differential limiting amplifier which adopts a staggered active feedback and capacitance degeneration circuit and is used for amplifying the voltage signal to a voltage level needed for a digital processing unit, and an output buffer stage which is used for converting an output differential voltage signal into a single-ended output voltage signal. On the premise of keeping the overall gain and bandwidth of the circuit, the introduced noise is reduced, and the sensitivity of optical receivers is improved.