Abstract: A switched resonant power amplifier system for ultrasonic transducers is disclosed. The system includes an amplifier that receives and processes a driver output signal for generating a drive signal that is provided to an ultrasonic device for controlling output of the ultrasonic device. An output control circuit receives and processes a signal related to a feedback signal generated by the ultrasonic device and a divider reference signal, and generates a compensated clock signal that is adjusted for at least one of phase and frequency differences between the received feedback signal and the divider reference signal. A compensated drive circuit receives and processes the compensated clock signal for generating the divider reference signal, and for generating the driver output signal.

Abstract: The present disclosure describes an instrument for measuring the dielectric properties of biological tissue. The instrument includes a top electrode assembly and a bottom electrode assembly, the top electrode assembly including a top electrode and at least one shaft adjustably positionable to move the top electrode relative to the bottom electrode assembly, the bottom electrode assembly including a bottom test plate and a bottom electrode. The instrument also includes a testing cylinder coupled to the shaft and having an inner cavity defined therein that houses the top electrode and which is designed to enclose the bottom electrode therein. The testing cylinder is configured to reduce at least one of electric current, magnetic current, stray radiative RF fields and external capacitive leakage currents during activation of the top and bottom electrodes.

Abstract: A switched resonant power amplifier system for ultrasonic transducers is disclosed. The system includes an amplifier that receives and processes a driver output signal for generating a drive signal that is provided to an ultrasonic device for controlling output of the ultrasonic device. An output control circuit receives and processes a signal related to a feedback signal generated by the ultrasonic device and a divider reference signal, and generates a compensated clock signal that is adjusted for at least one of phase and frequency differences between the received feedback signal and the divider reference signal. A compensated drive circuit receives and processes the compensated clock signal for generating the divider reference signal, and for generating the driver output signal.

Abstract: A method for electrosurgically sealing a tissue includes steps of: (A) applying a first pulse of RF energy to the tissue; and (B) applying at least one subsequent RF energy pulse to the tissue and keeping constant or varying RF energy parameters of individual pulses of subsequent RF energy pulses in accordance with at least one characteristic of an electrical transient that occurs during the individual RF energy pulses. The method terminates the generation of the at least one subsequent RF pulse upon a determination that the electrical transient is absent.

Abstract: A system and method for transmitting electrosurgical energy from a generator to an electrosurgical instrument are provided. The electrosurgical system includes a generator adapted to generate electrosurgical energy for treating tissue. The generator includes one or more active output terminals which supply energy to the tissue. The active output terminals are operatively connected to one or more supply lines. The generator also includes one or more return output terminal which returns energy from the tissue. The return output terminals are operatively connected to at least one return line. The system also includes an electrosurgical instrument operatively connected to the one or more supply lines and one or more return electrodes operatively connected to one or more return lines. The system further includes an electrosurgical cable including one or more supply lines and one or more return lines.

Abstract: The present disclosure describes an instrument for measuring the dielectric properties of biological tissue. The instrument includes a top electrode assembly and a bottom electrode assembly, the top electrode assembly including a top electrode and at least one shaft adjustably positionable to move the top electrode relative to the bottom electrode assembly, the bottom electrode assembly including a bottom test plate and a bottom electrode. The instrument also includes a testing cylinder coupled to the shaft and having an inner cavity defined therein that houses the top electrode and which is designed to enclose the bottom electrode therein. The testing cylinder is configured to reduce at least one of electric current, magnetic current, stray radiative RF fields and external capacitive leakage currents during activation of the top and bottom electrodes.

Abstract: A method for electrosurgically sealing a tissue includes steps of: (A) applying a first pulse of RF energy to the tissue; and (B) applying at least one subsequent RF energy pulse to the tissue and keeping constant or varying RF energy parameters of individual pulses in accordance with at least one characteristic of an electrical transient that occurs during the individual RF energy pulses. The method terminates the generation of subsequent RF pulses upon a determination that the electrical transient has passed a predetermined limit.

Abstract: A system for heat ablation of tissue in a patient comprises a plurality of electrodes operatively connected to a source of radiofrequency energy and configured to apply RF energy to tissue at a patient site, a plurality of RF current restricting circuits, each circuit coupled between one of the plurality of electrodes and the source of radiofrequency energy, and configured to restrict RF energy to the electrode when the current restricting circuit is enabled and not restrict RF energy to flow to the electrode when the current restricting circuit is disabled, at least one return electrode adapted to contact the patient and configured to return RF energy to the RF source; and a switching mechanism configured to selectively enable each of the plurality of RF current restricting circuits, in one of a sequential and non sequential fashion, wherein the switching mechanism is isolated from each of the current restricting circuits.

Abstract: An electrosurgical system is disclosed comprising a generator configured to electrosurgical coagulation waveforms. The generator includes a closed loop control system for controlling the electrosurgical coagulation waveforms. The closed loop control system includes a sensor configured to sense a tissue property and/or an energy property and to transmit the tissue property and/or the energy property as one or more sensor signals having an amplitude. The control system also includes a gain controller configured to process the at least one sensor signal to reduce the amplitude of the sensor signals and to obtain a signal to noise ratio of the at sensor signals within a predetermine range. A microprocessor coupled to the generator and is configured to adjust the electrosurgical coagulation waveforms as a function of the sensor signals.

Abstract: A method for electrosurgically sealing a tissue includes steps of: (A) applying a first pulse of RF energy to the tissue; and (B) applying at least one subsequent RF energy pulse to the tissue and keeping constant or varying RF energy parameters of individual pulses of subsequent RF energy pulses in accordance with at least one characteristic of an electrical transient that occurs during the individual RF energy pulses. The method terminates the generation of the at least one subsequent RF pulse upon a determination that the electrical transient is absent.

Abstract: A method for electrosurgically sealing a tissue includes steps of: (A) applying a first pulse of RF energy to the tissue; and (B) applying at least one subsequent RF energy pulse to the tissue and varying RF energy parameters of individual pulses of subsequent RF energy pulses in accordance with at least one characteristic of an electrical transient that occurs during the individual pulses of the subsequent RF energy pulses. The method terminates the generation of subsequent RF pulses upon a determination that the electrical transient has passed a predetermined limit.

Abstract: A method for electrosurgically sealing a tissue includes steps of: (A) applying a first pulse of RF energy to the tissue; and (B) applying at least one subsequent RF energy pulse to the tissue and varying RF energy parameters of individual pulses of subsequent RF energy pulses in accordance with at least one characteristic of an electrical transient that occurs during the individual pulses of the subsequent RF energy pulses. The method terminates the generation of subsequent RF pulses upon a determination that the electrical transient has passed a predetermined limit.

Abstract: A method for electrosurgically sealing a tissue includes steps of: (A) applying a first pulse of RF energy to the tissue; and (B) applying at least one subsequent RF energy pulse to the tissue and varying RF energy parameters of individual pulses of subsequent RF energy pulses in accordance with at least one characteristic of an electrical transient that occurs during the individual pulses of the subsequent RF energy pulses. The method terminates the generation of subsequent RF pulses upon a determination that the electrical transient has passed a predetermined limit.

Abstract: A method for electrosurgically sealing a tissue includes steps of: (A) applying an initial pulse of RF energy to the tissue, the pulse having characteristics selected so as not to appreciably heat the tissue; (B) measuring a value of an impedance of the tissue in response to the applied pulse; (C) in accordance with the measured impedance value, determining an initial set of pulse parameters for use during a first RF energy pulse that is applied to the tissue; and (D) varying the pulse parameters of individual ones of subsequent RF energy pulses in accordance with at least one characteristic of an electrical transient that occurs during subsequent RF energy pulses. The method terminates the generation of subsequent RF energy pulses upon a determination that the electrical transient is absent or that a minimum output voltage has been reached.

Abstract: A control system and method for the operation of neurosurgical bipolar electrodes for application to the tissue and bodily fluids of a patient provides a source of high frequency energy connected to bipolar electrodes. Contacting surfaces are on the bipolar electrodes of highly electrically conductive material with resistance per unit area substantially less than the impedance of the tissue and bodily fluids. A current transducer attached to the source of high frequency energy responds to the RMS current applied through the tissue and bodily fluids between the contact surfaces as a measure relative to the instantaneous values of the RMS current. A current transducer attached to the source of high frequency energy responds to the RMS current through a capacitor applied across the contact surfaces to provide a signal correlated to the instantaneous values of the RMS voltage between the contacts and across the tissue and bodily fluids.

Abstract: An apparatus and method are provided for performing parametric measurements using sensor transducer devices to recover frequency variant, amplitude modulated information from encoded sensory signals. A unique network is employed to achieve low-impedance current sensing in conjunction with analog signal decoding. More particularly, the network includes a circuit for current sensing the desired parameter and providing an analog sensor output signal related to the unit measure (i.e., relative value) of the desired parameter. The network also includes a circuit for receiving the demodulating the sensor output signal to obtain a signal representing the electrical equivalence of the measured parameter. The circuit for demodulating employs synchronous sampling techniques and includes a subcircuit, closed-loop through which the demodulated output is fed for generating an offset or error correcting signal.

Abstract: A cathode ray tube display system and method having bidirectional line scanning are disclosed. Bidirectional line scanning is achieved by scanning each odd numbered scan line from left to right and each even numbered scan line from right to left, thereby avoiding the necessity for retrace, or flyback. In order to avoid loss of intelligibility in displaying the video information received from a conventional source providing video information written only from left to right, as is conventional, the received video information is stored in memory by scan lines with each odd numbered line being read out in the same order as stored in memory and each even numbered line being read out in reverse order as stored in memory. Timed control is provided for processing of the video information and display thereof with bidirectional scanning, and geometric error correction is provided for both the horizontal and vertical scan generators.