Tektronix, Inc.

Michael R Engbretson

Jerry L Wrisley

Theodore G Nelson

J Steve Lyford

Charles L Saxe

Garry N Link

Frank Goovaerts

H Wayne Oldstead

James L Williamson

A simplified user interface for an electronic test and measurement device comprises an arrangement of a segmented LCD device and a plurality of keys used to implement a softkey system, in combination with a single AMPs input connector and a rotary selector having only a single position for each basic kind of parameter to be measured. The segmented LCD device includes, at each location adjacent to a key, a plurality of segments representing a vertically-arranged list of functions to be controlled. In one embodiment of the invention, the housing of the electronic test and measurement device is fabricated to have finger-like projections overlaying a portion of the LCD screen for creating the appearance of the continuation of displayed LCD softkey separation lines.

Simplified user interface and control system for a multimeter

An integrated oscillator includes an amplifier having first and second voltage inputs, and first and second current outputs, and a current mirror having an input coupled to the second current output of the amplifier and an output coupled to the first current output of the amplifier. The output of the current mirror and the first current output of the amplifier are coupled through a bonding pad to an external capacitor. A first comparator has a first input coupled to the first current output of the amplifier and a second input for receiving a first threshold voltage, and a second comparator has a first input coupled to the first current output of the amplifier and a second input for receiving a second threshold voltage. A flip-flop has a first input coupled to the output of the first comparator, a second input, and an output coupled to the second voltage input of the amplifier. A first multiplexer has a first input for receiving a reference voltage, a second input coupled to the output of the second comparator, and an output coupled to the first voltage input of the amplifier. A second multiplexer has a first input coupled to the output of the second comparator, a second input for receiving an enable signal, and an output coupled to the second input of the flip-flop. The output of the second comparator forms a one-shot output node responsive to the enable signal, and the output of the flip-flop forms a free-running oscillator output node.

Convertible oscillator circuit

Growing community of inventors

Beaverton, OR, United States of America

Michael R Engbretson