Tektronix, Inc.

Oregon Health & Science University

Tran Thong

Pei-hwa Lo

Shiv K Balakrishnan

Embodiments of the present invention provide apparatuses and methods to predict and/or prevent episodes of ventricular tachyarrhythmia (for example, ventricular tachycardia and/or ventricular fibrillation). A method is provided for predicting an episode of ventricular tachyarrhythmia by detection and analysis of multiple patterns of vagal fatigue and/or a threshold-exceeding heart.

Ventricular tachyarrhythmia prediction and/or prevention

Embodiments of the present invention provide apparatuses and methods to predict and/or prevent episodes of ventricular tachyarrhythmia (for example, ventricular tachycardia and/or ventricular fibrillation). A method is provided for predicting an episode of ventricular tachyarrhythmia by detection and analysis of multiple patterns of vagal fatigue during a period of time.

A method is provided for displaying complex waveforms, where one of amplitude or phase is graphed versus time and the color or grayness of the curve, or the area under the curve, represents the other of amplitude or phase at the time of the first measurement.

Method for presenting complex number waveforms

The present invention provides a method of displaying characteristics of a signal, where minimum amplitude of the signal during an interval is graphed versus time, maximum amplitude of the signal during the interval is graphed versus time, and the color or greyness of the area between the minimum amplitude graph and the maximum amplitude graph represents the average frequency during the interval of the amplitude measurements.

Method for displaying signal characteristics

A direct digital synthesizer (DDS) for generating an output periodic waveform from a stored digital waveform has a linear feedback shift register coonfigured as a counter. The linear feedback shift register is clocked by the internal reference clock of the DDS, and a predetermined output of the linear feedback shift register is detected to provide a control signal. The control signal causes the frequency or phase of the output waveform to be changed according to control parameters input to a control logic circuit. The control logic circuit preloads the new parameter vlaues into appropriate frequency/phase registers which are switched to the input of the accumulator in the DDS on the next cycle of the reference clock when the control signal is detected.

Direct digital synthesizer with feedback shift register

A pair of waveforms in quadrature relation, or otherwise phase related, are generated from a single direct digital synthesizer employing a single wave lookup table memory. Successive addresses are applied to the memory representing the desired phase difference between the two waveforms plus a fractional part of the increment desired between successive samples along the waveforms. Samples are selected for reconstructing the two respective waveforms by dividing down the sampling clock and providing timing signals therefrom coincident with the correct samples.

Generation of phase related waveforms

A sequence of n sample values occurring during a recording interval is processed by determining which of the sample values is the smallest and which of them is the largest. The smallest sample value is loaded into one of first and second memory portions in dependence upon whether the smallest value occurred before or after the largest sample value, and the largest sample value is loaded into the other of the first and second memory portions. In this fashion, the order of the smallest and largest sample values is preserved.

Digital storage oscilloscope with indication of aliased display

A method and apparatus are disclosed which provide for the removal of distortion present in a digital output signal from a linear analog signal processing system. Two applications are disclosed: digital compensation and digital equalization. Digital compensation provides for the removal of distortion from a single signal processing system. In particular, an adaptive digital filter operates to provide processing of an output signal from the signal processing system in accordance with correction criteria determined by a controller in response to a training signal. Digital equalization is employed with respect to a plurality of signal processing systems, and provides equalization of an output signal from one signal processing system in accordance with characteristics of a selected signal processing system. In particular, output signals from a selected signal processing system and a signal processing system desired to be equalized are employed to provide information to a controller for use with a correction criteria in the determination of correction information. The correction information is used to direct an adaptive digital filter coupled to an output of the signal processing system which is desired to be equalized.

Method and apparatus for digital compensation and digital equalization

A probe body for a measurement system comprises a probe-tip terminal for connection by way of a probe tip to a test point, a cable port for connection by way of at least one cable to a measurement instrument, probe circuitry, a function generator, and a switch. In a first state of the switch, the input terminal of the probe circuitry is connected to the probe-tip terminal and in a second state of the switch the input terminal of the probe circuitry is connected to the function generator. When the switch is in the second state, the function generator may be used to impress a signal having a predetermined waveform on the probe circuitry.

Probe body for an electrical measurement system

A method and apparatus are disclosed which provide for the generation of a trigger signal responsive to the detection of a plurality of selected sequential events in a single monitored signal. A plurality of trigger detect devices operate independently to monitor a signal for the occurrence of selected trigger criteria, and produce indications thereof having selected durations. The duration of the indications function to provide continuous indications of the occurrence of the selected trigger conditions over the periods thereof. In one embodiment, a state machine delays each of the indications by an amount of time approximately equal to the time between the respective events and a final event in the sequence, thereafter combining the indications according to preselected logical operations. As a result of the delays, the indications from the trigger detect devices are combined at approximately the same time. The duration of the indications operate to preclude timing differences between events from preventing detection of the series of selected sequential events. In an alternate embodiment, the state machine operates to combined information from the trigger detect devices in a serial fashion according to pre-selected logical operations and delayed by selected time periods to produce the desired trigger signal. Timing differences between sequential events are again precluded from preventing detection of the series of selected sequential events by the duration of the continuous indication produced by each of the trigger detect devices.

Multi-level pattern detector for a single signal

An electronic probe assembly provides previously recorded data as to probe identification and optimum compensation tuning of the probe to a connected 'intelligent' test and measurement device so that proper test procedures may be confirmed, either by display of such data or by the generation of error messages.

Electronic probe having automatic readout of identification and status

A sequence of digital data values is processed by deriving the average W.sub.n of two of the data values X.sub.n-1 and X.sub.n+1. If W.sub.n lies within the quantization step q centered on the data value X.sub.n, W.sub.n is adopted as a modified value of X.sub.n, but if W.sub.n lies outside the quantization step the modified value of X.sub.n is taken to be X.sub.n +q/2 or X.sub.n -q/2, depending on whether W.sub.n is greater or less than X.sub.n.

Apparatus for processing a sequence of digital data values

A method and apparatus for measuring characteristics of a component color video signal. In one embodiment the luminance component of a color video signal is applied to the vertical input of a cathode ray tube display device and a chrominance component is applied to the horizontal input. The resultant dots and transitions therebetween produced by the display trace provide an indication of component bandwidth, amplitude and relative time between components. All components can be compared simultaneously by alternately applying one chrominance component with the luminance component, and the other chrominance component with an inverted luminance component. In another embodiment one chrominance component is applied to the vertical input and the other is applied to the horizontal input. Delay circuits are provided for use with a time-division multiplexed video signal to compare time multiplexed components simultaneously. A graticule is provided for relating the display trace to a standard display.

Method and apparatus for measurement of component video signal

A method and system for reconstruction of chroma component segments in a line sequential chroma format television system. Filtering of a received line sequential chroma signal is employed to reconstruct missing chroma components and to attenuate phantom frequency components greater than one half the spatial sampling rate. Digital and analog filters are disclosed for implementation of such post filtering. The luminance component of the line sequential signal is delayed at the transmitter to synchronize the reconstructed chroma segment with its corresponding luminance segment with the use of minimal hardware at the receiver. Horizontal offset chroma sampling is used along with such post filtering to decrease transmission bandwidth requirements without sacrificing horizontal resolution at the receiver.

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Beaverton, OR, United States of America

Tran Thong