Tektronix, Inc.

Steven R Bingold

Jeffrey A Kleck

Kenneth P Dobyns

Andrew J Burkhardt

A multi-standard vide option for an oscilloscope detects whether an input video signal has a bi-level or a tri-level horizontal sync pulse from a composite sync signal derived from the input video signal. A ramp signal is generated from the horizontal sync pulse having a slope of one polarity that changes to a slope of the opposite polarity when the horizontal sync pulse is tri-level. For a bi-level horizontal sync pulse the ramp is limited in magnitude and rapidly discharged at the end of the horizontal sync pulse. A digital output signal is generated from the ramp signal and has a width equal to the width of the horizontal sync pulse regardless whether it is bi-level or tri-level. From the type of horizontal sync pulse and the width or the number of lines per frame, a video standard is determined and is subsequently used to determine field identification and to automatically set up the horizontal sweep of the oscilloscope according to a selected video setup.

Multi-standard video option for oscilloscope

A potentiometer which provides the function of an on/off switch includes a center conductor connected to a conductive ring and a resistive element concentrically disposed about the conductive ring. The resistive element includes a pair of termination pads and one of the pads includes a branch which is situated outside the outer periphery of the resistive element. As a wiper arm traverses the resistive element it remains in contact with the branch for a brief distance and then loses contact with it. This causes the value of the resistance in the potentiometer to make an abrupt shift in magnitude which can be used to initiate various switching functions.

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Portland, OR, United States of America

Steven R Bingold