Browse Prior Art Database

Remote Loop Attachment

IP.com Disclosure Number: IPCOM000073514D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Betts, WK: AUTHOR [+3]

Abstract

In data transmission systems it is often necessary, or desirable, to transfer clocking of data from one clock source to another or to reclock data which has been subjected to phase shifts. The illustrated circuit shows both techniques used with a data set which provides its own transmit clock and received data clock.

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Remote Loop Attachment

In data transmission systems it is often necessary, or desirable, to transfer clocking of data from one clock source to another or to reclock data which has been subjected to phase shifts. The illustrated circuit shows both techniques used with a data set which provides its own transmit clock and received data clock.

At the output side of the data set, data is shifted through a shift register having n stages (TR) at twice the receive clock rate. Each stage TR of the shift register is connected by a switching gate to the outgoing transmission line. The receive clock and the transmit clock are applied to a clock control circuit, which operates one of the gates between the shift register stages and the transmission line, as a function of the phase deviation between the receive clock and the transmit clock, to effectively synchronize the data stream with the transmit clock.

At the input side of the data set, the data is reclocked so as to be in synchronism with the transmit clock provided by the data set. Here a similar technique is employed. The data is shifted into a register having stages (TR) by a data derived clock. The undelayed data and the data as delayed by the shift register stages, are applied via switching gates to the data set input. A clock control circuit selects the appropriate delay by comparing the phases of the transmit clock and the data derived clock.

If the receive clock and transmit clock are not identically of the same f...