165 results about "Test pulse" patented technology

In a pulsed laser diode driver an energy storage capacitor is continuously being charged to a supply voltage Vr. When a pulse is initiated, energy stored in the capacitor is delivered to the laser diode load. The capacitor voltage Vd at the end of a pulse is used to control Vr to ensure that Vd is maintained above a minimum voltage Vm required to ensure operation of a current control device (such as FET) just above saturation. Test pulses (such as with attenuated currents or reduced pulsewidth) may be fired to determine an initial optimum value for Vr. After a test pulse, a slightly high estimate for Vr may be used and may be iterated (incremented) down to an optimum value Vm during a firing burst. A digital processor may be used to calculate and store data to optimize the performance. Various embodiments are disclosed.

A radio frequency (RF) power amplifier protection system for a radio. The protection system utilizes a resistive tap connected to the drain of a power amplifier transistor and a high speed voltage detector. The protection system uses short, low-power tests pulses to determine the quality of an antenna load upon tuning the radio to an RF carrier frequency by transmitting the short test pulse. If the measured voltage value exceeds a calibrated value, the power of the RF transmitter is reduced for subsequent operation or the RF transmitter is shut down completely. The invention also includes a system and method for detecting when an antenna is disconnected from a radio using an low frequency AC signal to measure the resistance of an antenna connected to an RF transmitter.

A method, system, and apparatus for performing a lead condition assessment and/or a lead orientation determination associated with an implantable medical device (IMD). A first impedance is determined. The first impedance relates to the impedance relative to a first electrode and a portion of the IMD. A second impedance is determined. The second impedance relates to the impedance relative to a second electrode and the portion of the IMD. The first impedance is compared with the second impedance to determine an impedance difference. A determination is made whether the impedance difference is outside a predetermined tolerance range. Furthermore, artifact measured during impedance measurements or test pulses may be compared to assess lead orientation. An indication of a lead condition error is provided in response to determining that the impedance difference is outside the predetermined tolerance range.

The invention discloses dynamic real-time evaluation equipment for irreversible electroporation tissue ablation, which utilizes an electrode in an irreversible electroporation tumor treatment primarypulse application process to detect tissue impedance spectrum changes before and after pulse treatment. As that instability of the impedance spectrum signal measure by the applied pulse electrode andthe problem of reflect the limited ablation area are effectively avoided, the relationship between the impedance spectrum measured by different electrode pairs and the actual ablation size is established aft subsequent data processing according to the impedance spectrum variation measured by different electrode pairs. At the same time, the change of tissue electrical properties was obtained by applying small signal test pulse during the treatment, and the mathematical model was established to judge the tissue ablation condition. At that same time, the invention can combine the advantage of thesweep frequency method and the test pulse method respectively, and solve the important problem of dynamic monitoring of curative effect in the treatment process of ablation effect aft irreversible electroporation pulse treatment and immediate evaluation of curative effect after treatment.

A laser pulse shape measuring system to measure the pulse shape of pulses generated by a pulsed laser. Each pulse includes a pulse width and a peak wavelength. The system includes: a beam splitter coupled to the laser to separate each of the pulses into a test pulse and a probe pulse; a pulse width compression means coupled to the beam splitter to compress the pulse width of each probe pulse; a controllable delay means to control a time offset between each test pulse and a corresponding probe pulse; a nonlinear optical medium arranged such that the test beam path and the probe beam path intersect within it to generate wavelength converted pulses corresponding to intersecting pairs of pulses; a detector coupled to the nonlinear optical medium to detect the pulse energies of the wavelength converted pulses; and a processor to determine the pulse shape of the laser pulses.

Disclosed is a method for the diagnosis of conductor anomalies, such as an insulation failure resulting in a short circuit, in an implantable medical device, such as an implantable cardioverter defibrillator (ICD). Upon determining if a specific defibrillation pathway is shorted, the method excludes the one electrode from the defibrillation circuit, delivering defibrillation current only between functioning defibrillation electrodes. Protection can be provided against a short in the right-ventricular coil-CAN defibrillation pathway of a pectoral, transvenous ICD with a dual-coil defibrillation lead. If a short caused by an in-pocket abrasion is present, the CAN is excluded from the defibrillation circuit, delivering defibrillation current only between the right-ventricular and superior vena cava defibrillation coils. Determination that the defibrillation pathway is shorted may be made by conventional low current measurements or delivery of high current extremely short test pulses.

An apparatus for locating a fault within an optical fiber is disclosed. The apparatus, which can be formed as a part of a fiber-optic transmitter or as a stand-alone instrument, utilizes a vertical-cavity surface-emitting laser (VCSEL) to generate a test pulse of light which is coupled into an optical fiber under test. The VCSEL is subsequently reconfigured by changing a bias voltage thereto and is used as a resonant-cavity photodetector (RCPD) to detect a portion of the test light pulse which is reflected or scattered from any fault within the optical fiber. A time interval Δt between an instant in time when the test light pulse is generated and the time the reflected or scattered portion is detected can then be used to determine the location of the fault within the optical fiber.

The position of a disturbance on an optical link is evaluated, in particular where the disturbance is a time-varying disturbance. An optical time domain reflectometry technique is used in which a series of low coherence test pulses is launched by means of an optical pulse source into an the optical link, and the backscattered return signal is monitored. The test pulses pass through an unbalanced Mach Zhender interferometer with the result that for each test pulse, a pair of time-displaced pulse copies is launched onto the link. The backscattered return signal is passed through the same interferometer, which causes the pulse copies of each pair to become realigned and to interfere with one another. A time-varying disturbance is likely to affect each pulse copy of a pair differently. As a result, an abnormality such as a step is likely to occur in the backscattered signal. From the time position of an abnormality, the distance of the disturbance responsible is evaluated.

A system and method for measuring the speed of a fan is presented. The duty cycle of a pulse width modulated (PWM) power signal may control speed of the fan. The fan may generate tachometer pulses used for monitoring RPM of the fan. Very low frequency test pulses may be generated and provided via a test signal multiplexed with the PWM signal to obtain tachometer pulses present even when the PWM signal is deasserted. The frequency of the test signal may be determined based on the duty cycle of the PWM signal and may be dynamically updated using frequency divider values stored in a user programmable look-up table. The tachometer pulses may be used to reset a flip-flop whose data input is held high and a down counter, which may be operated at a frequency slightly lower than the frequency of the test signal, with the output of the down counter clocking the flip-flop. The output of the flip-flop may provide recreated tachometer pulses to a pulse counter that counts the number of pulses within a determined period of time, providing a measured RPM of the fan.

In a method and a device for the measurement of the mean temperature of components, a sequence of test pulses of increasing duration is applied to the component, the power of the pulses representing a state of operation of the component, a measurement of junction temperature being performed at the end of each pulse to obtain a curve representing the progress of the junction temperature of the component as a function of time on the basis of the temperature measurement points obtained at the end of each pulse. The disclosed method and device can be applied especially to determine the junction temperature of microwave electronic components working in continuous mode or in pulsed mode.

A liquid crystal display includes a liquid crystal display panel and a test circuit. The liquid crystal panel includes a number of scanning lines and a number of data lines cooperatively forming a pixel cell. The test circuit includes a control unit, a gate driving circuit, a data driving circuit and a detecting circuit. The gate driving circuit and the data driving circuit respectively provide a scan pulse and a test pulse to the pixel cells. The test pulse includes a first voltage. After a predefined period for providing the scan pulse and the test pulse to the pixel cells, the detecting circuit detects a voltage of the data lines, and determines the pixel cell is damaged if the voltage of the data lines is equal to the first voltage. A test circuit and a test method for detecting damaged pixel cells are also provided.