Browse Prior Art Database

Redriver for Two Way Bus

IP.com Disclosure Number: IPCOM000083852D
Original Publication Date: 1975-Aug-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Johnston, DJ: AUTHOR

Abstract

This description relates to a circuit which may be used to amplify a data signal as it travels along a bidirectional bus, such as a bidirectional bus that might exist between a number of computing systems or central processing units, where there are many points of control or intelligence.

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Redriver for Two Way Bus

This description relates to a circuit which may be used to amplify a data signal as it travels along a bidirectional bus, such as a bidirectional bus that might exist between a number of computing systems or central processing units, where there are many points of control or intelligence.

The need for amplification arises when there is a long distance between successive units on the bus, or when a larger number of units are on the bus than can be successfully driven by one transmitter. Since the data bus is bidirectional, the amplifier unit must have the ability to amplify in either direction. Simply connecting two amplifiers back-to-back will not solve the problem, because an open-feedback loop would be established which would tend to latch the amplifiers into a static digital state.

A circuit which will provide two-way amplification is shown. The two amplifier drivers 301 and 302 are controlled by the logical AND gates 303 and 304. These AND gates are each controlled by the presence or absence of data on the other gate by the lines 310 and 311.

The amplifier formed by the AND gate 303 and driver 301 amplifies data travelling from left to right; the amplifier formed by AND gate 304 and driver 302 amplifies data travelling from right to left. 321, which means that these points are at a positive electrical value and both negative ANDS will be disabled. Being disabled, the AND will produce one leg or input of the other AND. Therefore, the c...