1024 results about "Active filter" patented technology

When a user receives potential junk e-mail from an unknown sender address, an active filter installed in or cooperating with the user's e-mail system sends a challenge e-mail back to the sender address. Unless the user receives a correct response e-mail from the sender address and/or a response that meets formal criteria, the active filter rejects the original e-mail and blocks future e-mail from that sender address. The challenge preferably includes a question that the sender must correctly answer in his response. The question is such that only humans can interpret and respond to it correctly. For example, the question may relate to and/or be incorporated in an image in the challenge. Lists of approved and blocked sender addresses are compiled. The user may directly enter addresses in the address lists. Addresses to which the user has sent e-mail may also be included directly in the approved list.

The invention relates to a super capacitor energy storage type power quality compensator. A system structure comprises a compensation transformer, a series compensator, a parallel compensator, a super capacitor group, a current foldback circuit, a bidirectional DC/DC chopper circuit, a signal sampling circuit, a control circuit, a drive circuit, a human-computer interface and corresponding auxiliary circuits, which form a three-phase three-wire system topological structure. By utilizing the excellent characteristics of great power density, high charging and discharging speed and long cycle life of a super capacitor, the super capacitor energy storage type power quality compensator is matched with the DC/DC chopper circuit to form an energy storage control system which plays the roles of adjusting power and stabilizing the voltage of a direct current bus in work. The invention also has the functions of dynamic voltage recovery, active filter and reactive compensation and can ensure that a load can obtain rated sine voltage and the current of a grid is sine current with the same direction (unit power factor) with that of a voltage fundamental wave positive sequence active component, thereby comprehensively improving the quality of power. The invention has positive generalization and application value for both the public grid and users.

Solid state lighting devices and illumination methods involve use of multiple solid state emitters of different colored outputs (optionally including at least one white or near-white emitter). Operation of the solid state emitters is controlled with at least one circuit element to emphasize and/or deemphasize perception of at least one color of a target surface based upon a reflectance spectral distribution of the target surface. At least one emitter may have an associated passive or active filter; the filterable emitter and/or active filter may be operated to deemphasize perception of at least one color of a target surface. Activation and/or alteration of emphasis or deemphasis of perception of color of a target surface may be selected by a user or automatically controlled.

The invention relates to a method for finishing bacterium fixation by utilizing polyvinyl alcohol-borate secondary crosslinking, belonging to the field of water treatment. The method comprises the steps of: after mixing polyvinyl alcohol and bacteria in proportion, putting the mixture into saturated borate solution and carrying out first crosslinking fixation, after the fixation, taking out supernate and regulating pH of the supernate, carrying out second crosslinking fixation on the polyvinyl alcohol by utilizing the supernate in which the pH is regulated, and cleaning the polyvinyl alcohol after the fixation, so as to finish the whole fixation process. The method has the advantages that the damage to the bacteria in the fixation process is greatly reduced, and the phenomena of adhesion, water solubility and expansion are effectively reduced as well, thus providing conditions for large-scale industrial application of biologic active fillers and biologic active filter materials based on the polyvinyl alcohol.

A continuous-time domain Decision Feedback Equalizer (DFE) for use in a serial communication channel comprises in one embodiment a summer, a decision circuit, a capture flip-flop (FF) and an N-th order active filter. The DFE and its active filter operate in continuous time to give improved performance over a discrete-time DFE. In one embodiment involving a first-order active filter, the capture FF is outside the continuous-time negative feedback loop of the DFE and involves a differential signal amplifier. In another embodiment, the capture flip-flop is inside the DFE loop, and in a third embodiment the decision circuit comprises a comparator.

An active filter (300) generates multi-phase compensating current in an AC power supply system (10) that supplies a load (200). The filter (300) includes a compensating current output device (34) outputting multi-phase compensating current to an AC power line (50); and a controller (310) for controlling the compensating current output (340) such that the multi-phase compensating current compensates for current harmonics and power factor on said AC power line (50). The controller (310) estimates current harmonics and power factor compensating values as a function of multi-phase power measurements.

An amplifier having an active and passive gain stage connect to a load for driving a load according to a system analog input. A first embodiment of the amplifier in accordance with the present invention includes a logic network connected between a comparator network and a switching system, wherein the comparator network connects to the passive gain stage. Specifically, the active gain stage may include an active filter connected to receive an analog or digital input and provide a difference between the analog or digital input and the feedback signal relative to the gain factor of a gain unit connected to the active filter. The passive gain stage includes a passive filter. The logic network generates at least one switching signal which controls the switching system that includes at least one switching device to selectively provide power to the load. An output signal from the switching system provides output for the amplifier and is fed back to the active gain stage. In another embodiment, the output is a two-level signal and the passive and active filters are second order low pass filters, where the gain factor is about 25 or more. In yet another embodiment, the gain factor is approximately 250. Moreover, the amplifier may include a digital delta-sigma modulator connected to supply a two level input.

An apparatus for active feed forward electromagnetic interference (EMI) filtering, including, a noise detection circuit that receives EMI noise occurring at a noise source, and an active feed forward circuit operatively coupled to the noise detection circuit. The active feed forward circuit generates a noise canceling signal based on the EMI noise received by the noise detection circuit. The apparatus further includes a filter operatively coupled to the active feed forward circuit and the noise source, the filter adapted to receive the EMI noise occurring at the noise source and the noise canceling signal from active feed forward circuit, wherein the filter cancels the received EMI noise based on the received noise canceling signal to reduce EMI noise at a load.

A magnetic powder core comprises a molded article of a mixture of a glassy alloy powder and an insulating material. The glassy alloy comprises Fe and at least one element selected from Al, P, C, Si, and B, and has a texture primarily composed of an amorphous phase. The glassy alloy exhibits a temperature difference ΔT_x, which is represented by the equation ΔT_x=T_x−T_g, of at least 20 K in a supercooled liquid, wherein T_x indicates the crystallization temperature and T_g indicates the glass transition temperature. The magnetic core precursor is produced mixing the glassy alloy powder with the insulating material, compacting the mixture to form a magnetic core precursor, and annealing the magnetic core precursor at a temperature in the range between (T_g−170) K and T_g K to relieve the internal stress of the magnetic core precursor. The glassy alloy exhibits low coercive force and low core loss.

A fourth order delta sigma analog-to-digital converter is presented, comprising a passive delta sigma modulator including a passive filter, a quantizer, and a digital-to-analog converter in a first feedback loop, and an active filter having a large gain factor in a second feedback loop around the passive delta-sigma modulator.

A filter element formed from at least one flat layer of permeable filter medium alternating with at least one pleated layer in such a way that the resulting channels have an open, especially triangular, cross section, a first group of channels being tightly sealed at one end and a second group of channels being tightly sealed at the other end such that a fluid to be filtered flowing through the filter element from an incident flow side formed by one end face to a discharge side formed by the opposite end face, must pass through one of the layers, a seal for sealing the incident flow side from the discharge side of the filter element at an installation site, and each side of each channel of the first group which is spaced from the periphery of the filter element is bordered by a channel of the second group such that fluid can flow through the full area of the channels except for fold edges, and at least one group of channels is filled with adsorbent particles and closed by a gas-permeable fabric disposed over the corresponding end face of the filter element, the fabric pores being smaller than the adsorbent particles.

A hybrid conditioner for filtering harmonics in a power system that includes a non-linear load. The hybrid conditioner includes an active filter structured and controlled to filter one or more high-order harmonic currents of the fundamental frequency, and a passive filter structured to filter one or more low-order harmonic currents of the fundamental frequency. The active filter and the passive filter are electrically connected in parallel with one another. The hybrid conditioner may also be for providing reactive power compensation for the power system, wherein the active filter is further controlled to provide a compensatory reactive power for compensating for the reactive power that is consumed by the load. The hybrid conditioner may also provide oscillation dampening for the power system, wherein the active filter is further controlled to damp oscillating currents that exist between the passive filter and the AC source.

Leakage current through stray or parasitic capacitance (which is particularly large in devices such as photovoltaic cell arrays and which are damaged by such leakage currents) due to common mode switching noise in a full bridge single phase power converter is reduced at high frequencies by magnetically coupling the two phase legs on the AC side of the power converter and connecting mid points of the AC and DC sides of the power converter and is reduced at low frequencies by use of a feedback arrangement that modifies sinusoidal modulation of the switches of the full bridge converter to function as an active filter. The magnetic coupling for the two phase legs is designed in a simple manner to avoid saturation based on volt-second considerations.

A phase-locked loop (PLL) including an active filter, a voltage-controlled oscillator (VCO), two phase detectors, a charge pump and a digital-to-analog converter (DAC) is provided. The VCO generates an oscillation signal according to a control signal provided at an output of the active filter. The first phase detector generates a phase difference signal according to a reference signal and a feedback signal associating with the oscillation signal. The charge pump provides a charging current to a first input of the active filter according to the phase difference. The second phase detector generates a digital reference signal according to the phase difference between the reference signal and the feedback signal. The DAC converts the digital reference signal to an analog reference voltage and provides the analog reference voltage to the second input of the active filter.

A power converting device includes a single-phase multiplex converter used as an active filter and a control device. The single-phase multiplex converter includes multiple single-phase inverters connected in series at AC output sides. Each of the single-phase inverters converts DC power fed from a DC power supply into AC power. The control device includes hysteresis comparators and controls output voltage of the single-phase multiplex converter by gradational output voltage control, based on the sum of selectively combined output voltages of the multiple single-phase inverters. The control device controls the single-phase multiplex converter so that an output current follows a harmonic compensation reference currents, canceling harmonics leaking from a load to which the power converting device is connected.

Methods, systems, and computer program products for configurable alert delivery in a distributed processing system are provided. Embodiments include for each alert generated by an incident analyzer, applying, by the incident analyzer, active alert filters to the alert; wherein applying the active alert filters to the alert includes: creating, by the incident analyzer, a list of all active alert filters and a set of all active listeners; and for each active alert filter, running, by the incident analyzer, the active alert filter; if the active alert filter indicates that the alert should not go to one or more of the active listeners, removing, by the incident analyzer, the one or more active listeners from the set of all active listeners; if the active listeners set is empty, stopping, by the incident analyzer, processing of the alert; and if the active listeners set is not empty, selecting, by the incident analyzer, the next active alert filter from the active alert filter list.

An active filter with compensation to reduce Q-enhancement is disclosed. The filter may include a first amplifier and a second amplifier coupled to the first amplifier. The second amplifier having a negative feedback loop including a buffer having a plurality of compensation resistors. The compensation resistors may each have a value that results in the biquad filter having substantially zero Q-enhancement. The biquads may cascaded to form higher order filters.

Power switches of circuits at respective stages of a low noise amplifier, demodulators, low-pass filers, variable gain amplifiers, and analog-to-digital converters are controlled to be off by an operation control unit in a non-reception period of an impulse signal. An increase in power consumption due to the adoption of an active filter or a variable gain amplifier is compensated for by a reduction in power consumption through intermittent operations of the circuits at the respective stages according to on and off control of the power switches.

The invention relates to a dispensing device for a liquid medium, having a medium reservoir for accommodating the medium, having a dispensing opening for dispensing the medium from the medium reservoir, and having a pressure-equalizing channel which opens out into the medium reservoir and has a microbiologically active filter arrangement inserted therein.

According to the invention, the filter arrangement has a liquid filter oriented in the direction of the medium reservoir and a bacteria filter oriented away from the medium reservoir.

The invention refers to a new keyboard based in a polymeric, copolymeric or composite film (11) with piezo- and pyroelectric properties capable of receiving a tactile signal and giving a respond in the form of an electrical signal. The system described in this invention includes one or more keys (10), being each one of them made by a piezoelectric film (11) with electric conductive contacts, transparent or not, above and below the piezoelectric film and with the inferior layer of grounded electrodes (13). The present invention allows the use of just one piezoelectric film (11) without external power supply, the use of electrode connections which form the keys (10) that converge in one side of the keyboard and are available in the spots (12) to make the connection to the active filter circuits instead of amplifiers in the electronic readout, as well as the possibility of introduction of new functionalities in these keyboards identical to the ones of tactile sensors, upon distinction between a pyroelectric and a piezoelectric signal from a particular key, differing the signals generated by pressure variation or by temperature variation.