Browse Prior Art Database

Phasing System

IP.com Disclosure Number: IPCOM000097240D
Original Publication Date: 1962-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Bowen, J: AUTHOR

Abstract

This phasing system is used in test equipment for evaluating a data transmission line. It compares a pulse train generated by a remote transmitter with a similar train generated locally in a receiver. For correct operation, it is essential that the generators for the transmitter and receiver operate in phase.

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Phasing System

This phasing system is used in test equipment for evaluating a data transmission line. It compares a pulse train generated by a remote transmitter with a similar train generated locally in a receiver. For correct operation, it is essential that the generators for the transmitter and receiver operate in phase.

The phasing system shown includes a shift register 7 which has nine stages. It produces a random sequence by connecting outputs from stages 5 and 9 through an exclusive OR 8 back to the input via gate 14. It also produces a repeating single word pattern of eight bits by connecting the output of stage 8 back to the input via gate 14. An identical generator is used in the transmitter and, as long as the two generators start from the same point, the same sequence of pulses is generated by both.

This is accomplished by initially resetting all the stages of shift register 7 and bistable circuit 15. Then, received input pulses are applied to the first stage of 7 at terminal 12 via gate 13 until 7 is completely filled. The latter condition is indicated by an output at stage 9. This output is used to reset circuit 15. Such action cuts off input pulses to terminal 12 and opens gate 14. Thus, register 7 is left to generate digits independently of the input pulses from the point at which the two trains were in phase.

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