3340 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.

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.

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.

A power supply for a two-wire load control device supplies power to a microprocessor, which in turn controls the power supply. The power supply comprises an energy storage element, e.g., a capacitor, for producing a DC voltage for powering the microprocessor. The power supply comprises a high impedance circuit for allowing the energy storage element to receive energy at a first rate before the DC voltage is produced and the microprocessor is powered. The power supply further comprises a low-impedance circuit, i.e., a resistor in series electrical connection with a controllably conductive device, for allowing the energy storage element to receive energy at a second rate greater than the first rate. After starting up, the microprocessor is operable to selectively enable and disable the second energy-receiving circuit by rendering the controllably conductive device conductive and non-conductive, respectively. The microprocessor is operable to monitor the power supply and to control the amount of power delivered to an electrical load connected to the load control device in response to the monitoring of the power supply.

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.