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Synchronized Crystal Clock for Digital Transmission Systems

IP.com Disclosure Number: IPCOM000089972D
Original Publication Date: 1968-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Garrett, MJ: AUTHOR [+2]

Abstract

A synchronized crystal clock for digital transmission system includes a crystal-controlled oscillator, two or more binary counters, a set of four bit divider triggers and a pair of synchronizing triggers. The system provides a bit time divided into a plurality of basic divisions, for example, t1...t8, the basic oscillator pulses forming eight possible divisions of each of these times. If the received signal line changes from mark to space or from space to mark during t8 of one bit time or t1 of the next bit time as defined by the And function of bit divider triggers 2 and 4, one of the two synchronizing triggers is set. This causes a single-shot to fire resulting in a reset pulse to the clock triggers.

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Synchronized Crystal Clock for Digital Transmission Systems

A synchronized crystal clock for digital transmission system includes a crystal-controlled oscillator, two or more binary counters, a set of four bit divider triggers and a pair of synchronizing triggers. The system provides a bit time divided into a plurality of basic divisions, for example, t1...t8, the basic oscillator pulses forming eight possible divisions of each of these times. If the received signal line changes from mark to space or from space to mark during t8 of one bit time or t1 of the next bit time as defined by the And function of bit divider triggers 2 and 4, one of the two synchronizing triggers is set. This causes a single-shot to fire resulting in a reset pulse to the clock triggers.

If data transition occurs during t8, bit divider trigger 1 turns on earlier than normal making the clock run effectively faster. If the transition occurs during t1, the binary counters are reset resulting in delay to bit divider trigger 2 making the clock run effectively slower.

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