Browse Prior Art Database

Multi-level Encoded High Bandwidth Bus

IP.com Disclosure Number: IPCOM000110412D
Original Publication Date: 1992-Nov-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 4 page(s) / 209K

Publishing Venue

IBM

Related People

Huynh, DQ: AUTHOR [+2]

Abstract

This article describes a technique to either maximize the data transfer rate between two or more devices attached to the same system bus or to optimize the utilization of that system bus. It is aimed particularly at increasing the throughput of computer systems designed for multi-media applications with a high bandwidth requirement.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 41% of the total text.

Multi-level Encoded High Bandwidth Bus

       This article describes a technique to either maximize the
data transfer rate between two or more devices attached to the same
system bus or to optimize the utilization of that system bus.  It is
aimed particularly at increasing the throughput of computer systems
designed for multi-media applications with a high bandwidth
requirement.

      The technique which is named Multi-Level Encoded High Bandwidth
Bus (MLEHBB) consists of using multi-level signaling instead of the
current bi-level signaling (0 and 1) to move data from one or more
source points to one or more destination points in order to maximize
the system bus bandwidth.  Specifically, the source digital data is
encoded via a digital to analog converter (DAC) into a multi-level
signal before being transmitted through the high-speed bus to the
destination device which then converts the multi-level signal back
into binary-bit patterns via an analog to digital converter (ADC) for
further processing.

      A multi-level encoded bus allows more than two distinguishable
electrical signal levels to convey the information carried by a
digital signal source.  To convert the binary signal to an L = (2)n
level multi-level signal, an n-bit DAC is used, with n being an
integer greater than 1 (n = 1 for binary-level signaling).

      The application of the concept of multi-level signaling
normally linked with signal modulation and transmission in the field
of data communication is unique when applied to an internal
high-speed bus residing within a computer system.

      In multi-media system environments where high data transfer
rate and concurrent data transfer are critical to the system
performance, a multi-level encoded bus offers an advantage over a
conventional bi-level encoded bus because either more information
could be transferred over a bus line during one bus cycle, or less
time is required to transfer the same amount of data, thus freeing
the system bus for use by other devices.  Also, from another
perspective, for a given bus data bandwidth a fewer number of signal
lines are required in a multi-level bus than in a bi-level bus.  As
an example of performance comparison, for a 64-line bi-level bus
using current technology which operates at 20 MHz, the maximum
bandwidth is 160 Mbytes/sec.  The same arrangement which uses a
multi-level bus signal and a current DAC/ADC operating at 20 MHz
would give a maximum bandwith of 640 Mbytes/sec (bus settling time is
not included).

      As stated earlier, the MLEHBB is aimed particularly at
increasing the throughput of computer systems designed for
multi-media applications with high bandwidth requirements.  Even a
greater bandwidth bus can be obtained by combining the MLEHBB
technique with another technique, the High Speed Multipurpose Bus
(HSMB), which also aims at achieving the same goal.  The HSMB,
dynamically provides multiple communication paths between multiple
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