3389 results about "High impedance" patented technology

An electrosurgical generator has an output power control system that causes the impedance of tissue to rise and fall in a cyclic pattern until the tissue is desiccated. The advantage of the power control system is that thermal spread and charring are reduced. In addition, the power control system offers improved performance for electrosurgical vessel sealing and tissue welding. The output power is applied cyclically by a control system with tissue impedance feedback. The impedance of the tissue follows the cyclic pattern of the output power several times, depending on the state of the tissue, until the tissue becomes fully desiccated. High power is applied to cause the tissue to reach a high impedance, and then the power is reduced to allow the impedance to fall. Thermal energy is allowed to dissipate during the low power cycle. The control system is adaptive to tissue in the sense that output power is modulated in response to the impedance of the tissue.

The invention is primarily directed to hot-stick mountable wireless High Voltage Power Line Universal Monitors (PLUM) upon energized electrical power conductors. The PLUM wireless sensors monitor parameters associated with normal, overload and emergency operation of the power line. The present invention provides 0.2% metering grade voltage measurement accuracy through unique e-field measurements, synchronized through UltraSatNet Global Positioning Satellite (GPS) accuracy timing pulses. The invention further improves accuracy using a unique calibration technique during initial installation of the PLUM sensor modules. A PLUM master controller receives time-synchronized data from multiple modules within a substation and across a state-wide power grid for accurate post-fault, sequence-of-events analysis, high impedance fault signature analysis, and environmental and earthquake monitoring.

Method and apparatus for control of ablation energy and electrogram acquisition through multiple common electrodes in an electrophysiology catheter. A device that routes ablation energy to and that routes mapping signals received from an electrophysiology catheter having a plurality of conductive filaments including circuitry that provides, for each conductive filament when ablation energy is being delivered, an electrical signal path that has a low impedance for ablation energy and a high impedance for mapping signals. The device also includes circuitry that provides, for each conductive filament, when mapping signals are being received, an electrical signal path that has a high impedance for ablation energy and low impedance for mapping signals. At least one switch is provided that selectively groups electrodes into sectors for delivery of ablation energy.

An implantable electronic medical device is compatible with a magnetic resonance imaging (MRI) scanner. The device has a housing with exterior walls, each formed by a dielectric substrate with electrically conductive layers on interior and exterior surfaces. A series of slots divide each layer into segments. Segmenting the layers provides high impedance to eddy currents produced by fields of the MRI scanner, while capacitive coupling of the segments provides radio frequency shielding for components inside the housing. Electrical leads extending from the housing have a pair of coaxially arranged conductors and traps that attenuate currents induced in the conductors by the fields of the MRI scanner.

Method and apparatus for control of ablation energy and electrogram acquisition through multiple common electrodes in an electrophysiology catheter. A device that routes ablation energy to and that routes mapping signals received from an electrophysiology catheter having a plurality of conductive filaments including circuitry that provides, for each conductive filament when ablation energy is being delivered, an electrical signal path that has a low impedance for ablation energy and a high impedance for mapping signals. The device also includes circuitry that provides, for each conductive filament, when mapping signals are being received, an electrical signal path that has a high impedance for ablation energy and low impedance for mapping signals. At least one switch is provided that selectively groups electrodes into sectors for delivery of ablation energy.

A catheter includes a plurality of primary leads to deliver energy for ligating a hollow anatomical structure. Each of the primary leads includes an electrode located at the working end of the catheter. Separation is maintained between the primary leads such that each primary lead can individually receive power of selected polarity. The primary leads are constructed to expand outwardly to place the electrodes into apposition with a hollow anatomical structure. High frequency energy can be applied from the leads to create a heating effect in the surrounding tissue of the anatomical structure. The diameter of the hollow anatomical structure is reduced by the heating effect, and the electrodes of the primary leads are moved closer to one another. Where the hollow anatomical structure is a vein, energy is applied until the diameter of the vein is reduced to the point where the vein is occluded. In one embodiment, a balloon is inflated to occlude the structure before the application of energy. Where the structure is a vein, the inflated balloon obstructs blood flow and facilitates the infusion of saline, medication, or a high-impedance fluid to the vein in order to reduce the occurrence of coagulation and to improve the heating of the vein by the catheter. The catheter can include a lumen to accommodate a guide wire or to allow fluid delivery.

The system generally includes a crosspoint switch in the local data collection system having multiple inputs and multiple outputs including a first input connected to the first sensor and a second input connected to the second sensor. The multiple outputs include a first output and a second output configured to be switchable between a condition in which the first output is configured to switch between delivery of the first sensor signal and the second sensor signal and a condition in which there is simultaneous delivery of the first sensor signal from the first output and the second sensor signal from the second output. Each of multiple inputs is configured to be individually assigned to any of the multiple outputs. Unassigned outputs are configured to be switched off producing a high-impedance state. The local data collection system includes multiple multiplexing units and multiple data acquisition units receiving multiple data streams from multiple machines in the industrial environment. The local data collection system includes distributed complex programmable hardware device (CPLD) chips each dedicated to a data bus for logic control of the multiple multiplexing units and the multiple data acquisition units that receive the multiple data streams from the multiple machines in the industrial environment. The local data collection system is configured to manage data collection bands.

An electrode assembly for use on a surface of biological tissue to measure bio-electric signals including an electrode apparatus having an electrode device adapted to directly contact the surface of the biological tissue. The electrode apparatus receives and transmits bio-electric signals measured across the biological tissue having a first voltage and a minute first current. A signal transmission line is included having a signal transmission conductor electrically coupled at one portion to the electrode device for transmission of the bio-electric signals. The transmission includes a second conductor electrically coupled to the amplifier apparatus and arranged to substantially shield the transmission conductor from ambient electric fields generated from sources external to the transmission line. A high impedance amplifier device is included having a signal input and a signal output. The signal input is electrically coupled to another portion of the signal transmission conductor for receipt of the transmitted bio-electric signals. The signal output is electrically coupled to the shield conductor, in a feedback loop, for receipt of at least a portion of the transmitted bio-electric signals, such that the voltage of the signals at the signal input of the high impedance amplifier device is maintained substantially equal to the voltage of the signals output from the signal output thereof.

Data line loading on high density modules with multiple DRAMs is minimized permitting the maximum memory density of systems of otherwise limited density to be increased without an ensuing performance degradation due to data line capacitive loading. First the single or dual in-line memory module (SIMM or DIMM) includes in-line bus switches. The bus switches are between the SIMM or DIMM module tabs (system) and random access memory devices (RAM) and are either in a high impedance (off) or active state depending on the READ / WRITE state of the RAM. When in the high impedance state, the effective loading of the module is that of the bit switch device. The logic for determining the READ / WRITE state may be embedded in an application specific integrated circuit (ASIC) that monitors bus activity and controls activation of the bus switches, be provided by a memory controller or, generated by the RAM itself. The bus switches are active when the RAM is performing a read or a write and inactive otherwise. The RAM is Fast Page Mode (FPM) and Extended Data Output (EDO) or Synchronous DRAM (SDRAM).

The present invention relates to an electronic circuit and an array of such circuits for precisely measuring small amounts or small changes in the amount of charge, voltage, or electrical currents. One embodiment of the present invention provides an electronic circuit for measuring current or charge that can be used with a variety of sensing media (including high impedance sensing media) that produce a signal by either charge or current production or induction in response to physical phenomena occurring within the sensing media. In another embodiment, the voltage level (bias) of either the sensing or reference electrode can be switched relative to the other upon receipt of a triggering pulse. This changes the polarity of the electric field to cause charge of the opposite polarity to be driven to the sensing electrode, thereby eliminating the need to electrically connect a discharge path to the sensing electrode to clear the charge accumulated at the sensing electrode. This can be supplemented by capacitively coupling a compensation signal to the sensing electrode to cause the amplifier output signal to lessen in magnitude below a threshold level that permits additional charge or current measurements of the same polarity before performing bias reversal. Alternately or in combination with bias reversal and capacitive compensation, sensor performance can be improved by minimizing inaccuracies caused by leakage currents or current drawn from the sensor. Other described methods of reducing leakage currents that can be used alone or in combination with the aforementioned features include the use of guard rings, physical switches or relays, the controlled creation of charges or currents of a specific polarity in a specific region of the sensing medium, controlled leakage over the surface of an insulator, and controlling the environment in which the circuit operates.

An electronic circuit for adding the effects of reverberation to a high impedance signal produced from an external audio source such as a guitar pickup or a high impedance microphone. The electronic circuit comprises a reverberation effects circuit having pre-amplifier / driver and recovery amplifier sections and a spring reverberation device coupled thereinbetween and a reverberation effects bypass at the circuit's input, prior to switchably passing the audio signal into an input of the pre-amplifier / driver section which comprises a low impedance, high current output for input into the spring reverberation device having an output for passing a low impedance signal to the recovery amplifier section, which suitably serves in increasing the impedance of the signal to a predetermined level acceptable for input into an external sound device such as an amplifier having channel inputs and audio control capabilities, and a power supply circuit having means for switching between a dc voltage source and an ac voltage source and supplying ±9 volts to integrated circuits (ICs) included in the pre-amplifier / driver and recovery amplifier sections of the reverberation effects circuit.

The system generally includes a crosspoint switch in the local data collection system having multiple inputs and multiple outputs including a first input connected to the first sensor and a second input connected to the second sensor. The multiple outputs include a first output and a second output configured to be switchable between a condition in which the first output is configured to switch between delivery of the first sensor signal and the second sensor signal and a condition in which there is simultaneous delivery of the first sensor signal from the first output and the second sensor signal from the second output. Each of multiple inputs is configured to be individually assigned to any of the multiple outputs. Unassigned outputs are configured to be switched off producing a high-impedance state. The crosspoint switch includes a third input that is configured with a continuously monitored alarm having a pre-determined trigger condition when the third input is unassigned to any of the multiple outputs.

An integrated transmit / receive (T / R) switch device comprises a substrate, an antenna port to couple with an antenna, a transmitter port to couple with a transmitter, and a receiver port to couple with a receiver. A receive path is provided between the antenna port and the receiver port, and a transmit path is provided between the antenna port and the transmitter port. The transmit path includes a first transistor on the substrate, and the first transistor is coupled in series between the antenna port and the transmitter port. A body node of the first transistor is unconnected, and the substrate is configured to provide a high impedance path from the first transistor to a reference voltage. A second transistor on the substrate is coupled in series between the receiver port and the reference voltage.

An electrode for a cardiac lead and method of making the same are provided. The electrode includes an electrode member and a coating applied to the electrode member. A method of fabricating a high impedance cardiac lead electrode is provided. The method includes the steps of providing an electrode member and coating a first portion of the electrode member with an electrically insulating material and placing a tubular mask or shield over the electrode. Portions of the insulating material are removed to expose selected areas of the electrode. The second or exposed portion enhances the impedance of the electrode, resulting in power savings and extended life spans for implantable stimulation and sensing devices. Exemplary materials for the coating includes diamond-like carbon and sapphire.

High-impedance optical electrodes modulate light in response to a life-form bio-potential and then converts the modulated light to an electrical signal that provides traditional EEG and EEC type output. Light splitters are used to provide multiple electrodes and an electronic reference source. A pilot tone is used to achieve high sensitivity and synchronize multiple units while an optical phase-shift modulator is used to reduce optical noise.

Some embodiments are directed to MRI / RF compatible medical interventional devices. A plurality of spaced apart high impedance circuit segments are configured to have a high impedance at a high range of radiofrequencies and a low impedance at a low range of frequencies The high impedance circuit segments may comprise co-wound coiled inductors and can reduce, block or inhibit RJ-transmission along the lead system (20) during exposure to RF associated with a high-Held magnet MRI systems, while permuting passage of low frequency physiologic signals, treatments and / or stimuli The devices can include at least one electrode

An artificial magnetic conductor is resonant at multiple resonance frequencies. The artificial magnetic conductor is characterized by an effective media model which includes a first layer and a second layer. Each layer has a layer tensor permittivity and a layer tensor permeability having non-zero elements on the main tensor diagonal only.

A switch being turned off using an output open function of a power supply circuit, a cathode voltage Vss is not transmitted, an output terminal takes on a high impedance condition and, a probing being done into a pad of the cathode voltage Vss output terminal with a probe, an ammeter which measures a current is disposed between the probe 304 and an external power source Vsst, making an adjustment time cathode voltage Vsst equal to an image display time cathode voltage Vss.

An artificial magnetic conductor is resonant at multiple resonance frequencies. The artificial magnetic conductor is characterized by an effective media model which includes a first layer and a second layer. Each layer has a layer tensor permittivity and a layer tensor permeability having non-zero elements on the main tensor diagonal only.

An electrode for a cardiac lead and method of making the same are provided. The electrode includes an electrode member and a coating applied to the electrode member. A method of fabricating a high impedance cardiac lead electrode is provided. The method includes the steps of providing an electrode member and coating a first portion of the electrode member with an electrically insulating material and placing a tubular mask or shield over the electrode. Portions of the insulating material are removed to expose selected areas of the electrode. The second or exposed portion enhances the impedance of the electrode, resulting in power savings and extended life spans for implantable stimulation and sensing devices. Exemplary materials for the coating includes diamond-like carbon and sapphire.

Ultrasound bulk wave transducers and bulk wave transducer arrays for wide band or multi frequency band operation, in which the bulk wave is radiated from a front surface and the transducer is mounted on a backing material with sufficiently high absorption that reflected waves in the backing material can be neglected. The transducer is formed of layers that include a high impedance section comprised of at least one piezoelectric layer covered with electrodes to form an electric port, and at least one additional elastic layer, with all of the layers of the high impedance section having substantially the same characteristic impedance to yield negligible reflection between the layers. The transducer further includes a load matching section comprised of a set of elastic layers for impedance matching between the high impedance section and the load material and, optionally, impedance matching layers between the high impedance section and the backing material for shaping the transducer frequency response. For multiband operation, the high impedance section includes multiple piezoelectric layers covered with electrodes to form multiple electric ports that can further be combined by electric parallel, anti-parallel, serial, or anti-serial galvanic coupling to form electric ports with selected frequency transfer functions. Each electric port may be separately transceiver-connected to obtain parallel, anti-parallel, serial or anti-serial port coupling for multi-band transmission, and extremely wide-band reception.

Medical apparatus includes a pacing generator, which has first active and indifferent outputs and is configured to generate electrical pacing pulses between the first active and indifferent outputs for pacing a heart of a subject. A radio frequency (RF) generator has second active and indifferent outputs and is configured to generate RF electrical energy of a predetermined frequency between the second active and indifferent outputs for application to the heart of the subject simultaneously with the pacing pulses. A filter includes a first branch connected between the first and second active outputs and a second branch connected between the first and second indifferent outputs, each of the first and second branches including one or more notch filters having a high impedance in a vicinity of the frequency of the RF electrical energy.

DC inductive FSS technology is a printed slow wave structure usable for reduced size resonators in antenna and filter applications of wireless applications. It is a dispersive surface defined in terms of its parallel LC equivalent circuit that enhances the inductance and capacitance of the equivalent circuit to obtain a pole frequency as low as 300 MHz. The effective sheet impedance model has a resonant pole whose free-space wavelength can be greater than 10 times the FSS period. A conductor-backed DCL FSS can create a DC inductive artificial magnetic conductor (DCL AMC), high-impedance surface with resonant frequencies as low as 2 GHz. Lorentz poles introduced into the DCL FSS create multi-resonant DCL AMCs. Antennas fabricated from DCL FSS materials include single-band elements such as a bent-wire monopole on the DCL AMC and multi-band (dual and triple) shorted patches, similar to PIFAs with the patch / lid being a DCL FSS.

A transponder 20 for an electronic identification system transponder is characterized in that it presents a high input impedance (>400 OMEGA ) at an input thereof which is directly connected to an antenna 22 with a matched high input impedance. The transponder is aimed at improving the voltage recovered on capacitor C2 from an interrogation signal and thus the operational range of the system. The modulator 30 of the transponder is arranged to backscatter modulate the interrogation signal at a modulation depth of less than 80%, preferably in the order of 30%. This also results in an improvement of the operational range of the system.

Circuitry and techniques designed to allow stable and continuous delivery of alternating power to a plasma with switch-mode power supply (16) include a variety of embodiments. Parallel, series, and other circuit elements connected across switching element (7) are tuned so that energy at other than the fundamental frequency is absorbed and dissipated. This energy may be only at the second harmonic or it may be across broad frequency ranges through selecting high impedance at the fundamental frequency and relatively low impedance at other frequencies. In overcoming instabilities, oscillations, and even changing class of operation of the switch-mode power supply, the stabilizing element absorbs the energy to avoid allowing it to affect switch (7) of power supply (16).