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Half Rate System for Data Transmission

IP.com Disclosure Number: IPCOM000091427D
Original Publication Date: 1968-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Croisier, A: AUTHOR [+2]

Abstract

Consider a data transmission system comprising an emitter E and a receiver R functioning normally at the rate of S bauds. The length of each data element d is T = 1/S and, for transmission, data elements can be subjected to any suitable coding. It may be necessary to use such a system for transmission of data which arrives at a half-rate and which must be restituted at the rate at which it arrives. Data A...F, arriving at rate S/2, is set under the form illustrated by line 2 of drawing 1 where data AB is set under the form AB but at the rate S, when repeated under this new form. The same process is applied to data CD and so on. Data, as in line 2, arrive on the emitter in the form of a normal series of data d and is eventually coded by any coding applicable process.

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Half Rate System for Data Transmission

Consider a data transmission system comprising an emitter E and a receiver R functioning normally at the rate of S bauds. The length of each data element d is T = 1/S and, for transmission, data elements can be subjected to any suitable coding. It may be necessary to use such a system for transmission of data which arrives at a half-rate and which must be restituted at the rate at which it arrives. Data A...F, arriving at rate S/2, is set under the form illustrated by line 2 of drawing 1 where data AB is set under the form AB but at the rate S, when repeated under this new form. The same process is applied to data CD and so on. Data, as in line 2, arrive on the emitter in the form of a normal series of data d and is eventually coded by any coding applicable process.

The first advantage of this disposition from transmitting end, i.e., disposition where data is repeated, is that a signal is obtained whose useful spectrum is narrower than the spectrum normally corresponding to any data d. This repetition operation is equivalent to filtering the signal with a transfer function H (Omega) = cos (Omega/2) = cos Omega T, T being the length of a normal data element.

A second advantage of this disposition is that, data being repeated, the message is redundant. At the receiving end, it is possible for recovery of data at rate S/2 to use the device of drawing 2 which produces the sum Sigma of the signal received at the instant t with th...