316results about "Frequency selective two-port networks" patented technology

A device for implementing a non-reciprocal bandpass filter is provided. The device includes a plurality of capacitively-coupled shunt resonators. Each capacitively-coupled shunt resonators includes a plurality of superconducting quantum interference devices (SQUIDs) connected to each other, a flux line inductively coupled to the plurality of SQUIDs, and a capacitor connected in parallel to the plurality of SQUIDs.

To provide a filter stage system.SOLUTION: A filter stage system includes a continuous time baseband filter comprising a feedback loop that employs at least one first impedance node and at least one second impedance node. The at least one first impedance node has a higher impedance than the at least one second impedance node. The at least one first impedance node provides a dominant pole, and the at least one second impedance node provides a non-dominant pole. The continuous time baseband filter generates a filtered current. The filter stage system also includes a mirroring component that mirrors the filtered current to an output.SELECTED DRAWING: Figure 2

A filter stage system comprising a continuous-time baseband filter comprising a feedback loop employing at least one first impedance node and at least one second impedance node, wherein the at least one first impedance node has a higher impedance than the at least one second impedance node, and wherein the at least one first impedance node provides a dominant pole and the at least one second impedance node provides a non-dominant pole, and wherein the continuous-time baseband filter generates a filtered current, and a mirror component mirrors the filtered current to an output.

The present application relates to the technical field of communications, and in particular to a switch-based compact phase shifter and an integrated phase shifter, which solve the problems of excessive size and costs of existing phase shifters. The switch-based compact phase shifter comprises: a first filter network, the first filter network being an Nth order high-pass filter network; a second filter network, the second filter network being an Mth order low-pass filter network; and a third filter network, the third filter network being an Rth order low-pass filter network; wherein: the first filter network, the second filter network, and the third filter network are connected in parallel by means of a double-pole three-throw switch; and when the second filter network is turned on alone, the insertion phase of the switch-based compact phase shifter is a reference phase; when the third filter network is turned on alone, the insertion phase of the switch-based compact phase shifter is a first phase; when only the first filter network and the second filter network are turned on, the insertion phase of the switch-based compact phase shifter is a second phase; and when only the first filter network and the third filter network are turned on, the insertion phase of the switch-based compact phase shifter is a third phase.

The invention belongs to the technical field of radio frequency amplification circuits, and particularly discloses a short-wave receiving amplification circuit capable of realizing cascade transmission and a short-wave communication system. According to the invention, direct current and interference in a previous-level signal are filtered through the filtering module, a pure radio frequency signal is obtained, and a foundation is laid for subsequent processing; the signal strength is improved through the amplification module, and single-stage transmission attenuation is overcome; the key point is that the balance gain module applies gain processing which is compensated for the loss characteristic of a transmission link to the amplified signal, so that the signal strength can be accurately matched with the actual loss of the line, and the problem that a fixed gain mode cannot adapt to the multi-stage series accumulated loss is solved. Compared with the prior art, the scheme realizes stable cascade transmission of short-wave signals through cooperative work of the modules, and remarkably improves the transmission distance and reliability of the system through dynamic compensation accumulated loss.

An electronic device may have wireless circuitry that includes transceiver circuitry, first and second antennas, and first and second transmission line paths that couple the transceiver circuitry to the antennas. The transceiver circuitry may convey a first radio-frequency signal using a first radio access technology (RAT) over the first transmission line path and the first antenna and may concurrently convey a second radio-frequency signal using a second RAT over the second transmission line path and the second antenna. The wireless circuitry may include a switched notch filter on the first transmission line path and a switched bandpass filter on the second transmission line path. The switched notch filter may be a conjugate of the switched bandpass filter. The transceiver circuitry may scan the first radio-frequency signal over a set of bands while concurrently conveying the second radio-frequency signal without reconfiguring the filters.

The invention provides an electroencephalogram signal anti-interference circuit based on internal and external cooperative inhibition of a chip, belongs to the field of electroencephalogram signal acquisition anti-interference, and is used for solving the problems that in the prior art, single internal or external anti-interference measures are difficult to cooperate, and the adaptability to complex noise is limited. The circuit comprises an external anti-interference circuit (comprising an electrode interface, a shielding protection module, a signal preprocessing module and a programmable filtering array) and a chip internal circuit (comprising a special filtering module, an interference suppression module, a pulse coding module and a double-domain analysis module), and parameter collaborative optimization is realized through a dynamic adjustment module, so that the anti-interference capability of electroencephalogram signals can be improved; signal stability and accuracy are enhanced, and a complex noise environment is adapted.

A method for designing frequency filters, includes (a) setting up a simulation model of a power supply system with frequency filters; (b) determining initial set of filter parameters; (c) calculating the model using the filter parameters in time domain; (d) extracting safety-critical trajectories from the calculated model with underlying interference functions; (e) transforming safety-critical trajectories from time domain into frequency domain; (f) determining transfer functions in s-domain by system identification; (g) extracting pairs of residuals and poles based on transfer functions in s-domain; (h) determining energy loss and voltage stability values based on the residuals and poles; (i) varying the filter parameters; (j) repeating (c)-(h) with the filter parameters varied in step (i), until a termination criterion is reached; (k) after which, selecting, from a set of points with energy loss and voltage stability values determined in step (h), a point lying on a pareto-front of the set of points.

The invention discloses a high-isolation and high-selectivity filtering power divider with an input end broadband non-reflection characteristic. Comprising an input port, two output ports, a double-L-shaped non-reflection absorption structure, two microstrip connecting lines, two parallel coupling lines, two L-shaped step resonators, two non-reflection absorption isolation resistors, a quarter-wavelength parallel coupling connecting line and two U-shaped transmission lines. The input port is a first port; the two output ports comprise a port II and a port III; the double-L-shaped non-reflection absorption structure comprises a first non-reflection absorption resistor, a second non-reflection absorption resistor, a first L-shaped non-reflection absorption connecting line and a second L-shaped non-reflection absorption connecting line. According to the invention, the broadband reflection-free absorption characteristic of the input end and the broadband high isolation between the output ports are realized at the same time, a plurality of transmission zeros are introduced through the L-shaped step resonators, and the frequency selectivity and out-of-band rejection are improved.

A coupled resonator filter including a first parallel resonator including a first capacitance connected in parallel with a first inductance. The filter includes a second parallel resonator including a second capacitance connected in parallel with a second inductance and a third parallel resonator including a third capacitance connected in parallel with a third inductance. Magnetic coupling between the first inductance and the second inductance, between the second inductance and the third inductance, and between the first inductance the third inductance occurs in accordance with first, second and third coupling factors, respectively. A frequency response of the coupled resonator filter includes a notch when values of the first coupling factor, the second coupling factor and the third coupling factor satisfy predetermined conditions.

The utility model relates to a Ka frequency band multichannel frequency conversion assembly in the field of spaceflight measurement and control. The Ka frequency band multichannel frequency conversion assembly comprises a front selection filter, a low noise amplification unit, a switch selection network unit, a multichannel frequency conversion unit and an assembly power supply and control unit. Wherein each channel comprises a front selection filter and a low-noise amplification unit; the switch selection network is used for shunting each path of input signal and selecting the signal through a multi-stage switch; the multi-channel frequency conversion unit completes frequency conversion of multi-channel signals and frequency multiplication, shunting and amplification of local oscillation signals; and the external imaging baseband unit issues control data to the component power supply and control unit to control the switch selection network output signal. According to the utility model, each frequency conversion link is subjected to twice frequency conversion, filters are arranged before and after frequency conversion, and the link spurious suppression degree is high. According to the utility model, all the modules are designed in an integrated manner, interconnection cables do not exist among the modules, the integration level is high, the reliability is high, the stray is less, and the anti-interference capability is strong.

The present invention relates to a method for operating a differential filter device (1) which can be calibrated and which comprises: a first branch (2), in particular provided for a main signal; a second branch (3), in particular provided for a complementary signal which is inverted in comparison with a main signal; first calibration means (4) for setting at least one filter frequency of the first branch (2); and second calibration means (5) for setting at least one filter frequency of the second branch (3); in which method at least one filter frequency of the first branch (2) is set using the first calibration means (4) and / or at least one filter frequency of the second branch (3) is set using the second calibration means (5), the at least one filter frequency of the first branch (2) being different from the at least one filter frequency of the second branch (3).

A coupled resonator filter including a first parallel resonator including a first capacitance connected in parallel with a first inductance. The filter includes a second parallel resonator including a second capacitance connected in parallel with a second inductance and a third parallel resonator including a third capacitance connected in parallel with a third inductance. Magnetic coupling between the first inductance and the second inductance, between the second inductance and the third inductance, and between the first inductance the third inductance occurs in accordance with first, second and third coupling factors, respectively. A frequency response of the coupled resonator filter includes a notch when values of the first coupling factor, the second coupling factor and the third coupling factor satisfy predetermined conditions.

The application relates to the technical field of tunable N-path filter, in particular to a tunable N-path reflection-free filter and a superheterodyne receiver. The tunable N-path reflection-free filter comprises a signal source, an N-path band-pass filter unit, an N-path band-stop filter unit, an output resistor and a phase-splitting clock generating circuit. The output end of the signal source is connected with one end of the N-path band-pass filter unit and the N-path band-stop filter unit respectively, the other end of the N-path band-stop filter unit is connected with the output resistor, the gate of a plurality of MOS switches in the N-path band-pass filter unit and the N-path band-stop filter unit is connected with the phase-splitting clock generating circuit, and the phase-splitting clock generating circuit outputs a control signal. The tunable N-path reflection-free filter provided by the application has excellent frequency selectivity, can effectively suppress high-order harmonics, and can adjust the passband and the stopband by changing the switching frequency. Meanwhile, the filter can eliminate the reflected signal, prevent the intermodulation interference and gain fluctuation of the mixer and the high-gain amplifier in the system.

The invention relates to a circuit (100) for providing a current source with a defined operating point, in particular a defined zero point, comprising - comprising an operational amplifier (OP), ◯ a first entrance (10), ◯ a second entrance (20), ◯ an output (30) which can be connected to a load (V), wherein the output (30) is configured to output a current (I) with a defined operating point, - a first signal generator (MC1) connected to the first input (10) to feed a first signal (PWM1) into the first input (10), - a second signal generator (MC2) connected to the second input (20) to feed a second signal (PWM2) into the second input (20), - wherein the first signal (PWM1) and the second signal (PWM2) have at least temporarily an identical pulse width in order to generate a defined operating point at the output (30). Furthermore, the invention relates to a system comprising such a circuit (100).

Analog front-end (AFE) system with an anti-aliasing filter circuit including a filter bypass switch configured to provide charge injection and / or clock pass-through independent of an input signal, wherein the AFE system comprises: at least one sampling capacitor of an analog-to-digital converter (ADC) circuit configured to sample an output of the anti-aliasing filter circuit; an amplification or buffer circuit with an input for receiving the input signal; and the anti-aliasing filter circuit coupled to an output of the amplification or buffer circuit, wherein the filter circuit comprises the following: a filter resistor; a filter capacitor coupled to one terminal of the filter resistor; and the filter bypass switch, which is connected in a bootstrapped configuration to pull a control terminal of the filter bypass switch above or below a supply voltage, wherein the filter bypass switch is connected in parallel to the filter resistor, wherein the filter bypass switch has an ON state and an OFF state, wherein, when in the ON state, the filter bypass switch is configured to bypass the filter resistance, allowing the amplification or buffer circuit to drive the at least one sampling capacitor through the filter bypass switch; and wherein, when in the OFF state, the filter bypass switch is designed to cause the amplification or buffer circuit to drive the at least one sampling capacitor through the filter resistor.

According to some embodiments, a receiver comprises a positive terminal, a negative terminal, a first isolation capacitor connected to the positive terminal, a second isolation capacitor connected to the negative terminal, a resistor circuit connected to the first isolation capacitor and the second isolation capacitor to define a first high pass filter, an amplifier connected to the first high pass filter, a level detector connected to the amplifier, and a second high pass filter connected between the first high pass filter and the level detector.

The invention relates to an EMC discrete noise compensation circuit, and the circuit comprises a noise generation module which is used for generating a square signal and a gain adjustment signal based on a discrete noise signal, and the square signal and the discrete noise signal are the same in frequency and are opposite in phase; the gain amplification module is used for generating a noise compensation signal which counteracts the discrete noise signal based on the square wave signal and the gain adjustment signal; and the signal coupling module is used for coupling the noise compensation signal to an EMC (Electro Magnetic Compatibility) port of the electronic equipment so as to offset the discrete noise signal. According to the method, a specific noise source is introduced innovatively, the effect of totally compensating and counteracting the excessive noise signal is achieved by coupling the inverted same frequency noise signal and the original noise signal, various complex combination attempts such as filtering, suppression, bypass, shielding and grounding of traditional measures are abandoned, and the method is simple, clear and easy to implement.

This invention belongs to the field of microwave communication, specifically disclosing a low-parasitic amplitude modulation differential bridge T-type phase shifter. The ground terminals of the differential positive branch phase shifter circuit and the differential negative branch phase shifter circuit are connected to form a differential virtual ground. A first input port is connected to the input terminal of the differential positive branch phase shifter circuit via a matching circuit, and a second input port is connected to the input terminal of the differential negative branch phase shifter circuit via a matching circuit. The output terminal of the differential positive branch phase shifter circuit is connected to the first output port, and the output terminal of the differential negative branch phase shifter circuit is connected to the second output port. A first insertion loss adjustment circuit is connected in parallel between the matching circuit and the phase shifter circuit, and a second insertion loss adjustment circuit is connected in parallel between the phase shifter circuit and the signal output port. This invention reduces the difference in insertion loss between the bridge T-type phase shifter in the reference state and the phase shifter state, thus reducing parasitic amplitude modulation. This invention is applicable to phase control in phased array radar antenna elements.

Wireless circuitry can include a first filter circuit configured to output signals in a first frequency range, a second filter circuit configured to output signals in a second frequency range different than the first frequency range, and a signal combiner having a first input coupled to the first filter circuit and having a second input coupled to the second filter circuit. The wireless circuitry can further include a first switchable impedance matching circuit coupled between an antenna and the first filter circuit and a second switchable impedance matching circuit coupled between the antenna and the second filter circuit. The first and second filter circuits can be active filters such as lowpass-to-bandpass conversion filters operable in different frequency bands.

The utility model relates to a broadband anti-burning anti-crosstalk annular low noise amplifier assembly, which comprises an input end, a low noise amplifier assembly and an output end, the input end is connected with a band-pass filter, and the output end is connected with a low-pass filter; the band-pass filter is connected with the low-noise amplifier assembly, and the low-pass filter is connected with the low-noise amplifier assembly through the down-conversion mixer; the low-noise amplifier assembly is of a multi-stage cascade system structure and comprises a front-stage broadband low-noise amplifier, a rear-stage SPDT radio frequency switch, a biasing circuit with temperature and voltage compensation effects and an ESD protection circuit. The front-stage broadband low-noise amplifier is cascaded with the rear-stage SPDT radio frequency switch; the front-stage broadband low-noise amplifier and the rear-stage SPDT radio frequency switch are respectively cascaded with a biasing circuit with temperature and voltage compensation effects; the utility model has the advantages of reasonable structure, strong anti-interference performance, safety and reliability, and can avoid burnout.

The invention discloses a peak filter circuit capable of keeping the pulse width of an input signal, which comprises an input circuit, a first positive feedback filter circuit, a second positive feedback filter circuit and a filter output selection circuit, the output end of the input circuit is connected with the input end of the first positive feedback filter circuit and the input end of the second positive feedback filter circuit, and the output end of the first positive feedback filter circuit and the output end of the second positive feedback filter circuit are connected with the input end of the filter output selection circuit. The output end of the filter output selection circuit generates an output signal VOUT. According to the invention, the pulse width of the input signal can be maintained while the expected peak voltage is filtered, and the reliability of communication between chips is improved.

The invention discloses an FF-FB cooperative four-unit active filter based on dual-core multiplexing. The FF-FB cooperative four-unit active filter comprises a noise source part, a load LISN network part and an active filter part, the active filter part comprises a current sampling branch, a first operational amplifier module, a second operational amplifier module, a voltage sampling branch, a plurality of current compensation branches, a first complementary output stage circuit and a second complementary output stage circuit; the two ends of the noise source part are connected with the left side of the active filter part, and the load LISN network part is connected with the right side of the active filter part. Feed-forward current sampling-current compensation is completed by using the multiplexing operational amplifier, and compensation is completed at the source end and the load end of the current transformer through two branches, so that secondary structure multiplexing is realized, and the problem that the operational amplifiers are added in topology is solved.

A switching circuit outputs a modulated signal. A low-pass filter circuit receives the modulated signal and applies low-pass filtering processing at a low-pass cut-off frequency to generate a demodulated signal to a load impedance. A replicating circuit receives the modulated signal and applies a replica of the low-pass filtering processing of the low-pass filter circuit to generate a reference signal. A signal processing circuit applies signal processing to the demodulated signal and the reference signal to generate at least one indicator signal which is indicative of a variation of the low-pass cut-off frequency.

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.

Device for operating a passive infrared (PIR) detector with a first connection (IN) and a second connection (IP), the device comprising: - an electrical circuit arrangement (R G ), wherein the electrical circuit arrangement (R G ) forms a leakage resistance between the first terminal (IN) and the second terminal (IP) of the passive infrared detector (PIR) to discharge the first terminal (IN) and the second terminal (IP) of the passive infrared detector (PIR); wherein the electrical circuit arrangement (R G ) includes a switch-capacitor circuit with transfer gates and storage capacities; and the device is set up for this purpose: - the transfer gates of the electrical circuit arrangement (R G) to switch alternately with a first clock (φ1) and a second clock (Φ2), and to advance a charge quantity by one node with each half-clock using the storage capacities, whereby the first clock (φ1) and the second clock (Φ2) do not overlap and, apart from the non-overlap, the first clock (φ1) is the inverse of the second clock (Φ2); and - to switch off the first clock (φ1) and the second clock (Φ2) during a measurement phase, so that the device is in a measurement state and the charge flow through the electrical circuit arrangement (R G ) is prevented.

The invention discloses an active damping method combining a wave trap with an amplitude attenuator, and relates to the technical field of power electronics. The invention aims to solve the problems that an inherent harmonic peak exists in a method for suppressing switch subharmonics by adopting an LCL type filter, noise at resonant frequency can be amplified, waveform quality is influenced, tracking errors are caused to a current loop of an ultra-precision linear servo system, and the positioning precision of a linear motor is influenced. According to the active damping method combining the wave trap with the amplitude attenuator, the wave trap and the amplitude attenuator are sequentially cascaded to the output end of the inverter, so that the wave trap and the amplitude attenuator form an active damper, and active damping is achieved.

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 invention discloses a low-power-consumption variable-gain double-second-order band-pass filter circuit with dB linearity, which is characterized in that a binary weighted complementary switch technology is introduced on the basis of an existing double-second-order band-pass filter, so that the effects of band-pass at a useful signal frequency point and adjustable gain in a pass band are realized, and compared with a band-pass filter in the prior art, the gain in the band-pass filter is adjustable. Under the condition that the power consumption of the circuit is not increased, the function that the gain is adjustable in the passband is achieved, the consistency of the flatness of the passband can be guaranteed, a single MOS tube is used for replacing OTA, and then the total power consumption and the area loss of the circuit are remarkably reduced. In addition, the variable-gain double-second-order band-pass filter can be used in various receivers with low power consumption requirements, and is wide in application range.