38results about "Frequency selective two-port networks" patented technology

An object is to provide a noise filter that can achieve high reliability. A noise filter includes: a noise detection unit which detects a common mode noise flowing through an electric path; an amplification unit which, on the basis of the common mode noise detected by the noise detection unit, generates a cancellation signal for canceling out the common mode noise; an injection unit which injects the cancellation signal into the electric path; an abnormality detection unit which detects abnormality of the noise filter on the basis of output voltage or output current of the cancellation signal, and outputs an abnormality detection signal; and a protection circuit which inhibits an abnormal cancellation signal from being injected into the electric path, on the basis of the abnormality detection signal.

This invention relates to a signal transmitter for a spatially distributed multi-parameter electrostatic sensor, comprising a first signal preprocessing circuit, a second signal preprocessing circuit, and a signal processing circuit. The first signal preprocessing circuit performs standard signal preprocessing and is used to multiplex signals from multiple sensors. The second signal preprocessing circuit includes N first signal amplification circuits, a signal superposition circuit, and a second signal amplification circuit. The first signal amplification circuits amplify the signals from each sensor, the signal superposition circuits superimpose the signals from multiple sensors, and the second signal amplification circuits amplify the superimposed signal. By using two different signal preprocessing processes, the appropriate preprocessing process can be selected according to different sensor signals, enabling reliable signal preprocessing.

The present invention provides an active inductive impedance enhancement circuit applied to a power line path. It utilizes a closed-loop control technique to detect residual high-frequency signals on the power line and generates a compensation current injected into the secondary side of the main inductor accordingly. The invention actively suppresses high-frequency current flowing through the main inductor, thereby significantly enhancing its impedance against high-frequency noise.

A power circuit contains one or more power supplies controlled by a controller, a sensor, and a filter. Each power supply has an electrical component designed to store energy. The sensor detects an initial current with a first bandwidth through the electrical component. The filter filters a signal based on the initial current to obtain a filtered current with a second bandwidth smaller than the first. The controller is configured to process the filtered current to produce an estimated current with a third bandwidth larger than the second.

The embodiment of the application provides a cascade anti-interference circuit suitable for an electrocardio monitoring device, which comprises a sliding mean filter module, a notch filter module, a lifting wavelet decomposition module, a threshold calculation module, a threshold processing module and a lifting wavelet reconstruction module; while ensuring a small circuit scale, the ECG signal collected by the wearable electrocardio monitoring device is subjected to hierarchical noise reduction processing, and high signal-to-noise ratio ECG signal output is realized; for the ECG signal collected by the wearable electrocardio monitoring device, first, sliding mean filtering is performed to filter out baseline drift noise caused by human respiratory movement and other activities; the power frequency interference caused by the wired and wireless connection of the electromagnetic environment around the device is suppressed by using the notch filter module; finally, wavelet noise reduction is realized by using the lifting wavelet decomposition and reconstruction and threshold noise reduction method, the electromyographic interference caused by the autonomous or unconscious movement of the wearer is suppressed, and high signal-to-noise ratio ECG signal is output, which is used for physiological parameter extraction and electrocardio diagnosis.

The application relates to a trans-impedance amplifier integrated with automatic reset and fast burst response, which comprises a trans-impedance amplifier front-end circuit, a reset signal automatic generation circuit in communication with the trans-impedance amplifier front-end circuit and an adjustable low-pass filter circuit; the adjustable low-pass filter circuit is in communication with an output signal of the trans-impedance amplifier front-end circuit and in communication with reset signals RST and inverse reset signals RSTB generated by the reset signal automatic generation circuit; the adjustable low-pass filter circuit is used for controlling MOS variable resistors and MOS switches arranged in the adjustable low-pass filter circuit according to the reset signals RST and the inverse reset signals RSTB and forming a low-pass filter with adjustable cut-off frequency, and a signal output by the low-pass filter with adjustable cut-off frequency conforms to a mean interval of a voltage signal output by the trans-impedance amplifier front-end circuit. An external RESET signal provided by an MCU is no longer needed to complete fast burst response of chips such as a trans-impedance amplifier, a limiting amplifier and a CDR.

To provide a switch device capable of performing overvoltage protection.SOLUTION: A switch device 100 comprises a first node N1, a switch unit SU1, an adjustment switch SWA, an impedance element R1, a second node N2, and a detection unit DU. A first terminal of the switch unit is coupled to the first node. A first terminal and a second terminal of the adjustment switch are coupled to a second terminal of the switch unit and a reference voltage terminal 150, respectively. A first terminal and a second terminal of the impedance element are coupled to the first terminal and the second terminal of the adjustment switch, respectively. The detection unit is coupled to the second node, a control terminal of the switch unit, and a control terminal of the adjustment switch. The detection unit detects a node signal SN of the second node, and generates a first control signal S1 and a second control signal S2 so as to control the switch unit and the adjustment switch.SELECTED DRAWING: Figure 1

The equalizer stage circuit includes a first transistor and a second transistor arranged in a differential configuration. The equalizer stage circuit also includes a first selectable path. The first selectable path includes a high-frequency section comprising a first terminal coupled to the emitter or source of the first transistor, a second terminal coupled to the emitter or source of the second transistor, and a first plurality of high-frequency RC time constant elements connected in parallel between the first and second terminals, and a low-frequency section comprising a first capacitor coupled to the first terminal, a second capacitor coupled to the second terminal, and a second plurality of low-frequency RC time constant elements connected between the first and second capacitors.

This application relates to a vibration signal acquisition system. The system includes: a vibration sensor; two filtering circuits, the input terminals of which are both connected to the output terminal of the vibration sensor; an ADC module, comprising: a first ADC unit and a second ADC unit, the input terminal of the first ADC unit being connected to the output terminal of one filtering circuit, and the input terminal of the second ADC unit being connected to the output terminal of the other filtering circuit. When the vibration sensor is in operation, the output terminal of the first ADC unit outputs a first digital signal, and the output terminal of the second ADC unit outputs a second digital signal; and an MCU module, which calculates the average value of the first and second digital signals to obtain a vibration digital signal. This system solves the problem of low accuracy and reliability of vibration signals acquired by existing vibration signal acquisition systems.

The present application provides circuits and methods for converting a wideband digital signal to a wideband analog signal. An integrated circuit includes a filter circuit that divides a wideband digital signal in the frequency domain to generate narrowband digital signals, each of the narrowband digital signals having a different frequency band; a digital-to-analog converter circuit that converts the narrowband digital signals to generate analog signals; and an analog combiner circuit that combines the analog signals into a single wideband analog signal.

The application provides a high-isolation transceiving simultaneous frequency conversion assembly, which comprises independently controlled SC frequency band receiving and transmitting links, X frequency band receiving and transmitting links, an SC frequency band transmitting intermediate frequency input port (J2) connected with the SC frequency band receiving and transmitting links, an SC frequency band receiving intermediate frequency output port (J1), an SC frequency band receiving radio frequency input port (J5), an SC frequency band transmitting radio frequency output port (J6), an X frequency band transmitting intermediate frequency input port (J3) connected with the X frequency band receiving and transmitting links, an X frequency band receiving intermediate frequency output port (J4), an X frequency band receiving radio frequency input port (J8), an X frequency band transmitting radio frequency output port (J7) and an interface (J9) for realizing connection of a low-frequency connector and an interference technology unit. The high-isolation transceiving simultaneous frequency conversion assembly can solve the problem of high-isolation transceiving simultaneity and achieve the goal of miniaturization.

Variable Gauge Analog Filter The present invention relates to a variable gauge analog filter (10) comprising, between an input (18) for a frequency signal (22) to be filtered and an output (20) for a filtered signal (24). The filter comprises a set of filtering impedances (26) with at least one variable capacitor (28, 32) disposed between a high point and a low point, and comprising a control input (21) for a control voltage (of the capacitor's capacitance). The variable capacitor (28) is a main transistor (28) whose source and drain form the high and low points respectively, the control input (21) being connected to the drain, the source and gate being connected to electrical potentials for operation of the main transistor (28) in a cutoff state. Figure for the abstract: Figure 1

To provide an isolated active EMI filter with no additional elements on the power line, in which active circuit elements are isolated from the power line, and a method for reducing EMI noise using the same.SOLUTION: An isolated active EMI filter 100 is an EMI filter for preventing noise emitted from a power line cable, and does not have any elements added to the power line. The isolated active EMI filter 100 includes a common mode choke 110 arranged on the power supply side, a Y capacitor 120 arranged on the EMI source side, a detection winding 130 that detects the noise current flowing through the common mode choke 110, an amplifier 140 that amplifies the noise current, and a transformer 150 that injects a signal from the secondary coil into the Y capacitor as a compensation signal.SELECTED DRAWING: Figure 1

In accordance with a first aspect of the present disclosure, an active RC-type filter is provided, comprising: an input, an output and a signal path between said input and output; at least one capacitor bank and at least one resistor bank, wherein said capacitor bank and resistor bank are integrated into the signal path; wherein the resistor bank comprises a plurality of resistor ladders; wherein each one of said resistor ladders comprises a plurality of resistors connected in series; wherein each one of said resistors has an input node configured to be coupled selectively to the signal path through one of a plurality of controllable switches; and wherein said resistor ladders have output nodes directly coupled to each other and to the signal path. In accordance with a second aspect of the present disclosure, a corresponding method of implementing an active RC-type filter is conceived.

According to a band-pass filter, n represents a natural number equal to or more than one, and the band-pass filter includes: an input terminal to receive an input of an RF signal; a multi-phase splitter to split the RF signal into n RF signals whose phases each differ by 360 degrees / n; n signal paths to receive from the multi-phase splitter, sample, and hold one of the n RF signals, and output the held signal, the n signal paths being connected to the multi-phase splitter, and each signal path including a sample hold element including two switches; a multi-phase synthesizer to synthesize n signals output from the n signal paths, the multi-phase synthesizer being connected to the n signal paths; an output terminal to output the signals to be synthesized by the multi-phase synthesizer; and a clock signal source to output a clock signal for driving all of switches.

An electronic filter for filtering multiple signals including a signal of interest and an other spectral content induces a desired frequency selective limiter response with activator signals. The activator signals have an approximately 180-degree phase difference and effectively cancel in a final combiner, leaving only the desired filter response.

Data transfer rates input to and output from electronic devices are a function of I / O pad circuit structure. The load capacitance of an I / O pad may reduce the bandwidth of an I / O circuit. A reduced pad capacitance circuit may be used to reduce or eliminate the positive and physical pad capacitance associated with a capacitive pad. This negative capacitance reduces or minimizes poor signal quality arising from large pad capacitance. This improved signal may be fed into a comparator, where the signal may be improved further using an equalizer. The use of negative capacitance circuit will increase the transmit and receive signaling quality of I / O interfaces.

The application discloses a CTLE (Continuous Time Linear Equalizer) based on a single amplifier and having a DC offset and common-mode voltage modulation function, and mainly solves the technical problem that the DC working point of the existing CTLE is easily affected by process deviation, input signal common-mode voltage and current mismatch, and an additional DC offset elimination loop is needed, thereby increasing the design and area complexity. The CTLE comprises a first-stage equalization unit EQ1, a second-stage equalization unit EQ2, a low-pass filter LPF, a frequency compensation unit and an offset and common-mode multiplexing amplifier OCMA. The CTLE adopts a single offset and common-mode multiplexing amplifier OCMA, simultaneously completes DC offset elimination and DC output control, and can reduce the design and area complexity.

The present invention relates to a variable-gauge analog filter (10) comprising, between an input (18) for a frequency signal (22) to be filtered and an output (20) for a filtered signal (24). The filter comprises a set of filtering impedances (26) with at least one variable-capacitance capacitor (28, 32) arranged between a high point and a low point, and comprising a control input (21) for a control voltage (Vds) of the capacitor's capacitance. The variable-capacitance capacitor (28) is a main transistor (28) whose source and drain form the high and low points, respectively, the control input (21) being connected to the drain, and the source and gate being connected to electrical potentials for operation of the main transistor (28) in a cutoff state.

A circuit includes a Sallen-Key filter and a programmable gain amplifier coupled to the Sallen-Key filter, the Sallen-Key filter including a source follower implementing a unity gain amplifier. The circuit is capable of implementing a programmable gain that decouples the bandwidth of the circuit from its gain setting via adjustment of a current mirror replication ratio in the programmable gain amplifier. The programmable gain amplifier can include a differential voltage-to-current converter, a current mirror pair, and a programmable output gain stage. At least one leg in the Sallen-Key filter and the programmable gain amplifier can include transistors arranged in the same circuit configuration.

Embodiments of the present disclosure provide a filter, an integrated passive device, an electronic device, and a display apparatus. The filter is applied in the field of radio frequency and includes: a first port, a second port, a first band-stop filter circuit, a low-pass filter circuit, a band-pass filter circuit, and a high-pass filter circuit. The first band-stop filter circuit is coupled to the first port, and is configured to perform out-of-band suppression on a signal input from the first port and input a signal subjected to the out-of-band suppression to the low-pass filter circuit. The low-pass filter circuit is configured to input a first signal, a frequency of which is between a first frequency and a second frequency, of the signal input by the first band-stop filter circuit to the band-pass filter circuit.

The application belongs to the technical field of phase sequence measurement, and particularly relates to a non-contact three-phase alternating voltage phase sequence measurement device, which comprises an internal reconstructed voltage module, an attenuation module, a filtering module, a comparison module and a main controller; the internal reconstructed voltage module comprises three, each internal reconstructed voltage module is used for forming corresponding internal reconstructed voltage of each phase in three-phase alternating voltage, and outputting the internal reconstructed voltage to the attenuation module; the attenuation module is used for attenuating and amplifying the internal reconstructed voltage of each phase; the filtering module is used for filtering the attenuated internal reconstructed voltage of each phase; the comparison module is used for generating each phase pulse signal according to the filtered internal reconstructed voltage of each phase; and the main controller is used for judging the phase sequence of alternating voltage according to the phase difference of rising edges of each phase pulse signal. The internal reconstructed voltage module is used to acquire the power frequency voltage of each phase in a non-contact conducting line mode, and the accuracy of the acquired power frequency voltage is effectively maintained.

One example includes a superconducting circuit system. The system includes at least one bias input configured to provide a bias current to a superconducting device via at least one superconducting device bias line coupled to the superconducting device during operation of the superconducting device. The system further includes a thermal transition filter system interconnecting the superconducting device bias line and the bias input. The thermal transition filter system provides a current path to divert noise current provided from the bias input away from the superconducting device during a temperature transition from a first temperature to a second temperature. The first temperature is greater than a highest superconducting critical temperature associated with the superconducting circuit system and the second temperature is less than a lowest superconducting critical temperature for the superconducting circuit system.

This invention provides a dual-mode reconfigurable compact CMOS ultra-wideband fourth-order bandpass filter, comprising: a first tunable second-order filter for acquiring an external differential RF signal and performing frequency selection processing on the external differential RF signal under the action of a first control signal to obtain a first frequency-selective differential signal; a second tunable second-order filter for acquiring the external differential RF signal and performing frequency selection processing on the external differential RF signal under the action of a second control signal to obtain a second frequency-selective differential signal; and an output stage for receiving the first and second frequency-selective differential signals and performing corresponding subtraction processing according to the polarity of the first and second frequency-selective differential signals to obtain a final output differential signal; the first and second control signals are calculated based on the target center frequency and the target in-band ripple using the parallel fourth-order bandpass filter synthesis principle. This achieves a significant improvement in tuning smoothness and integration.

This invention provides a variable Q-value dual second-order filter based on resistive feedback, belonging to the field of radio frequency receiver technology. The invention employs a differential source follower to construct the second-order filter unit and introduces a cross-coupled resistor network between the differential signal nodes, providing a novel method for adjusting the filter's quality factor. Through the equivalent feedback path formed by the cross-coupled resistors in differential operation, the filter's quality factor Q can be adjusted independently. Furthermore, a parasitic zero-point cancellation method is proposed, achieving negative capacitance by cross-coupling two capacitors between the differential input and output nodes, thereby improving stopband rejection performance. This structure achieves variable Q-value and high linearity without increasing filter power consumption, making it suitable for radio frequency receiver systems and showing promising engineering application prospects.

An electronic filter includes a splitter (14) that is configured to split a signal of interest and an other spectral content onto a first circuit leg (16) and a second circuit leg (18), and a signal generator (32,20, 34) that is configured to generate an activator signal. A first combiner (22) on the first circuit leg is configured to inject the activator signal at a frequency matching the other spectral content, and a second combiner (24) on the second circuit leg is configured to inject the activator signal at a frequency matching the other spectral content. The activator signal in the second circuit leg is phase shifted approximately 180 degrees relative to the activator signal in the first circuit leg. A first frequency selective limiter (26) on the first circuit leg is configured to attenuate both the activator signal and the other spectral content on the first circuit leg by a first dB of attenuation to a threshold power level of the first frequency selective limiter, and a second frequency selective limiter (28) on the second circuit leg is configured to attenuate both the activator signal and the other spectral content on the second circuit leg by a second dB of attenuation to a threshold power level of the second frequency selective limiter. A third combiner (30) is configured to generate a filter output based on combining the attenuated activator signal, the attenuated other spectral content, and the signal of interest from the first frequency selective limiter with the attenuated activator signal, the attenuated other spectral content, and the signal of interest from the second frequency selective limiter. The first and second frequency selective limiters may comprise spin wave limiters which are magnetostatic devices.

This invention provides a filter, comprising: an input port, an output port, two first resonant units, N second resonant units, and a first matching unit; the two first resonant units are respectively connected between the input port and ground and between the output port and ground, each first resonant unit including at least one first resonator; the N second resonant units are sequentially connected between the input port and the output port, each second resonant unit including at least one second resonator and at least one third resonator, wherein the second resonator is connected in series between the input port and the output port, and the third resonator is connected in parallel between the input port and the output port; the two ends of the first matching unit are respectively connected to the input ports of the two first resonant units. This invention also provides a duplexer and a multiplexer. Implementing this invention helps reduce the manufacturing difficulty of the device.

The application provides a multilayer structure filter and a vehicle-mounted power DCDC conversion device, wherein the multilayer structure filter comprises N layers of PCBs which are sequentially and spaced apart from top to bottom, and N is greater than or equal to 3; N-1 levels of output inductors which are sequentially and spaced apart from top to bottom, and each output inductor is connected to the adjacent upper and lower layers of PCBs through the input end and the output end; N-1 levels of output capacitors which are sequentially and spaced apart from top to bottom, and each output capacitor is connected to the second layer to the Nth layer of PCBs; and a filter output terminal which is connected to the output end of the N-1th level of output inductor. The multilayer structure filter and the vehicle-mounted power DCDC conversion device using the same are used for the output filter of the DCDC converter of the vehicle-mounted power conversion product, and a multilayer structure filter is provided, so that the filter is miniaturized to save the installation space, and the heat dissipation, filtering and shielding functions of the large-current path of the output end of the DCDC converter are better realized.

This product provides an active inductor that can achieve the functionality of a high-inductance signal inductor, which is difficult to obtain and expensive, using a simple circuit. [Solution] The configuration involves connecting a first feedback resistor (Rf) between the output of the main amplifier and the inverting input, and using the inverting input of the main amplifier as the input and the output of the main amplifier as the output, as an active inductor with voltage input and voltage output.

This invention discloses a dual-core multiplexed FF-FB cooperative four-unit active filter, comprising a noise source section, a load LISN network section, and an active filter section. The active filter section includes a current sampling branch, a first operational amplifier module, a second operational amplifier module, a voltage sampling branch, several current compensation branches, a first complementary output stage circuit, and a second complementary output stage circuit. The two ends of the noise source section are connected to the left side of the active filter section, and the load LISN network section is connected to the right side of the active filter section. This invention utilizes multiplexed operational amplifiers to complete feedforward current sampling and current compensation, achieving compensation at the source and load ends of the current transformer via two branches, thereby realizing a second structural multiplexing and solving the problem of increasing operational amplifiers with topology addition.