Browse Prior Art Database

Signal Skew Reduction

IP.com Disclosure Number: IPCOM000092155D
Original Publication Date: 1968-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Audretsch, LM: AUTHOR

Abstract

A tapered transmission line is used to shape a pulse front. By virtue of its progressive change in characteristic impedance, tapering a transmission line acts to change the magnitude of the signal voltage. As the pulse propagates down a tapered transmission line, the signal voltage increases as the square root of the increase in impedance. Thus, for an input impedance Zin of 50 ohms and an output impedance Zo of 100 ohms, the output voltage is 1.4 times the input voltage. The effect of this increase is to shape the pulses passing through the transmission line in the manner that counteracts pulse front distortion arising from skin-effect attenuation. This skin-effect attenuation manifests itself as a pronounced break in rise time occurring at about the magnitude of 50% of the pulse.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Signal Skew Reduction

A tapered transmission line is used to shape a pulse front. By virtue of its progressive change in characteristic impedance, tapering a transmission line acts to change the magnitude of the signal voltage. As the pulse propagates down a tapered transmission line, the signal voltage increases as the square root of the increase in impedance. Thus, for an input impedance Zin of 50 ohms and an output impedance Zo of 100 ohms, the output voltage is 1.4 times the input voltage. The effect of this increase is to shape the pulses passing through the transmission line in the manner that counteracts pulse front distortion arising from skin-effect attenuation. This skin-effect attenuation manifests itself as a pronounced break in rise time occurring at about the magnitude of 50% of the pulse. The result of this distortion, combined with variations in the up and down levels of circuits receiving the signal, can result in a time distribution of parallel signals, i.e., skew. By using a tapered transmission line in place of a conventional line, the thresholds of the receiving circuits occur below the 50% break point of the pulse, thus reducing skew in the outputs of such circuits.

1