569 results about "Impulse generator" patented technology

A data-modulated ultra wideband transmitter that modulates the phase, frequency, bandwidth, amplitude and / or attenuation of ultra-wideband (UWB) pulses. The transmitter confines or band-limits UWB signals within spectral limits for use in communication, positioning, and / or radar applications. One embodiment comprises a low-level UWB source (e.g., an impulse generator or time-gated oscillator (fixed or voltage-controlled)), a waveform adapter (e.g., digital or analog filter, pulse shaper, and / or voltage variable attenuator), a power amplifier, and an antenna to radiate a band-limited and / or modulated UWB or wideband signals. In a special case where the oscillator has zero frequency and outputs a DC bias, a low-level impulse generator impulse-excites a bandpass filter to produce an UWB signal having an adjustable center frequency and desired bandwidth based on a characteristic of the filter. In another embodiment, a low-level impulse signal is approximated by a time-gated continuous-wave oscillator to produce an extremely wide bandwidth pulse with deterministic center frequency and bandwidth characteristics. The UWB signal may be modulated to carry multi-megabit per second digital data, or may be used in object detection or for ranging applications. Activation of the power amplifier may be time-gated in cadence with the UWB source thereby to reduce inter-pulse power consumption. The UWB transmitter is capable of extremely high pulse repetition frequencies (PRFs) and data rates in the hundreds of megabits per second or more, frequency agility on a pulse-to-pulse basis allowing frequency hopping if desired, and extensibility from below HF to millimeter wave frequencies.

An apparatus and a method for treatment of benign prostatic hyperplasia are disclosed. The apparatus includes an applicator piece carrying a set of electrodes shaped and positioned to create a substantial electric field in the volume of hyperplasia and a pulse generator adapted for delivery of electrical pulses above the upper electroporation limit for the neoplastic cells. The amplitude, duration and number of the electrical pulses are generally selected to cause necrosis of a significant fraction of the volume of benign prostatic hyperplasia. The apparatus may include a high frequency system for heating the prostatic tissue and a cooling system for cooling the urethra. The combined action of heating and cooling may increase the temperature of the prostate cells to 45 degrees C. to 55 degrees C., while keeping the urinary tract at a temperature 15 degrees C. to 20 degrees C. This temperature distribution can increase the selectivity of the treatment by increasing susceptibility of the neoplastic cells to the electroporation treatment and decreasing it for the normal urethral tissues.

This invention discloses a valve that generates a hydraulic negative pressure pulse and a frequency modulator for the creation of a powerful, broadband swept impulse seismic signal at the drill bit during drilling operations. The signal can be received at monitoring points on the surface or underground locations using geophones. The time required for the seismic signal to travel from the source to the receiver directly and via reflections is used to calculate seismic velocity and other formation properties near the source and between the source and receiver. This information can be used for vertical seismic profiling of formations drilled, to check the location of the bit, or to detect the presence of abnormal pore pressure ahead of the bit. The hydraulic negative pressure pulse can also be used to enhance drilling and production of wells.

A system for treating a tissue site. At least first and second mono-polar electrodes are configured to be introduced at or near a tissue site of the patient. A voltage pulse generator is coupled to the first and second mono-polar electrodes. The voltage pulse generator is configured to apply sufficient electrical pulses between the first and second mono-polar electrodes to induce electroporation of cells in the tissue site, to create necrosis of cells of the tissue site, but insufficient to create a thermal damaging effect to a majority of the tissue site.

A transformer has a primary winding connected between a pair of dc input terminals via a switch, a secondary winding connected between a pair of output terminals via a first rectifying and smoothing circuit, and a tertiary winding connected to a second rectifying and smoothing circuit for feeding a switch control circuit. Included in the switch control circuit is a switch control pulse generator circuit whereby the switch is driven to provide a constant dc voltage at the output terminals. A mode selector circuit is connected to the switch control pulse generator circuit to cause the switch to be driven continuously under normal load, and at intervals under light load. The intermittent driving of the switch is suspended, and the switch driven continuously, in the event of a drop in the output voltage of the second rectifying and smoothing circuit to a predefined value during operation in light load mode.

Electrical energy is transcutaneously transmitted from an external charger to an implanted medical device. The external charger includes a charging head that is selectively shapeable to conform to the surface of a patient to enhance charge efficiency and patient comfort. An alternating current charging coil is housed in the charging head and configured for transcutaneously transmitting electrical energy to the implanted medical device. The shape of the coil is changeable as the charging head is shaped, and at least one sensor determines changes in the shape of the charging coil and causes the charge of the coil to be adjusted based on the coil shape.