Browse Prior Art Database

Ripple Sensing Keyboard

IP.com Disclosure Number: IPCOM000076623D
Original Publication Date: 1972-Mar-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Arosenius, L: AUTHOR

Abstract

A terminal keyboard system is shown in Fig. 1. The main elements are the keys themselves, which actuate contacts to generate an electrical signal, the decoder which identifies the depressed key and converts the identification to the proper binary code representation, and a signal adapter which serializes this information and adapts the signal to a form suitable for transmission over a telephone line.

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Ripple Sensing Keyboard

A terminal keyboard system is shown in Fig. 1. The main elements are the keys themselves, which actuate contacts to generate an electrical signal, the decoder which identifies the depressed key and converts the identification to the proper binary code representation, and a signal adapter which serializes this information and adapts the signal to a form suitable for transmission over a telephone line.

A top view of the keyboard is shown in Fig. 2. The keys are arranged in a row, and parallel to each row is a bar made of material with good acoustic transmission properties. At the end of the bar is a sensor which can be piezoelectric, magnetrostrictive, electrodynamic or electromagnetic, or any other type of sensor. Fig. 3 shows a side view of the key. The side of the key facing the bar has ridges or grooves which represent the code for the corresponding key in, for instance, delta code. A tongue is fastened to the bar in front of each key position, and when the key is depressed the tongue will wipe over the ridges or grooves in the key. The vibrations in the tongues are coupled to the bar, and the bar transmits acoustically these vibrations to the sensor in the end of the bar. The sensor produces signals which will, for normal key depression speeds, lie in the low-frequency range. The signal can, therefore, via a linear amplifier, be directly transmitted over a telephone line. The receiver will decode these signals. The keys are, apart from...