Browse Prior Art Database

Pulse Parameter Coding of Multiple Signals for Scanning Electron Microscopy of Microcircuits

IP.com Disclosure Number: IPCOM000078525D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Lukianoff, GV: AUTHOR [+2]

Abstract

In a system for displaying voltage distributions on microcircuits (as disclosed in IBM Technical Disclosure Bulletin Vol. 15, No. 8, pages 2547 and 2548, January 1973), multiple input signals are coded by applying the input signals at different temporal frequencies. These temporal frequencies are translated by the scanning process into distinctive spatial frequencies in the displayed image. Some microcircuits, however, require for their operation that more than one signal be at the same frequency (e.g. multiphase clock inputs in dynamic shift registers). In such cases, these signals cannot be coded distinctively by frequency differences.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 80% of the total text.

Page 1 of 1

Pulse Parameter Coding of Multiple Signals for Scanning Electron Microscopy of Microcircuits

In a system for displaying voltage distributions on microcircuits (as disclosed in IBM Technical Disclosure Bulletin Vol. 15, No. 8, pages 2547 and 2548, January 1973), multiple input signals are coded by applying the input signals at different temporal frequencies. These temporal frequencies are translated by the scanning process into distinctive spatial frequencies in the displayed image. Some microcircuits, however, require for their operation that more than one signal be at the same frequency (e.g. multiphase clock inputs in dynamic shift registers). In such cases, these signals cannot be coded distinctively by frequency differences.

Multiple inputs at the same frequency can be coded distinctively by several methods utilizing pulse parameters. Pulse-width coding, pulse-width modulation coding, and pulse-position modulation coding are the simplest and visually most distinctive methods. Related methods, such as pulse-shape coding or pulse- shape modulation coding may also be useful for special purposes, although they are less distinctive visually.

In pulse-width coding two or more signals are applied to the microcircuit with the same repetition rate, but with different pulse widths. The range of pulse width available is limited by constraints imposed by operation of the microcircuit itself, and by the scanning electron microscope scanning rates available that allow reso...