Browse Prior Art Database

Coding Used in Data Transmission System

IP.com Disclosure Number: IPCOM000091419D
Original Publication Date: 1968-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Gorog, E: AUTHOR [+2]

Abstract

Some codes, obtained from the 4-out-of-8 code, reduce the width of the transmission spectrum. It is possible to obtain such a code, called Transmission Adapted Code, from a 4-out-of-8 code by inverting every other bit, either all even or all odd bits. Furthermore, some transmission devices, to effect transmission of a series of data, send two data elements followed by their inverse, then the next data elements followed by their inverse, and so on.

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Coding Used in Data Transmission System

Some codes, obtained from the 4-out-of-8 code, reduce the width of the transmission spectrum. It is possible to obtain such a code, called Transmission Adapted Code, from a 4-out-of-8 code by inverting every other bit, either all even or all odd bits. Furthermore, some transmission devices, to effect transmission of a series of data, send two data elements followed by their inverse, then the next data elements followed by their inverse, and so on.

It is possible, with such type transmitters, to maintain the TAC type characteristics in the signals they deliver. With regard to the modulator-delivered signal, for example, signal, shown by link K, results from the transmission of a data x1, a data y1, the inverse of both, then of data x2 and y2 and their inverse. Such occurs as if all the elements corresponding to data xi are sent on one channel, line x, and as if all those corresponding to data yi are sent on an orthogonal channel in time. This is also applicable to other types of modulation modes close to the one mentioned.

If the data presented to the modulator is such that:

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then signal, delivered by the modulator, also possesses the TAC code characteristics.

The drawing shows an example of a device which, from the 4-out-of-8 coded data, drives the modulator with a series in which the terms are grouped so as to present the characteristics given in T. Two characters A and B are introduced in registers 1 and 1'. Elements a1...a8 and b1...b8, which make up both t...