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Browse Prior Art Database

Increased Resolution When Using Data Compression Techniques

IP.com Disclosure Number: IPCOM000043274D
Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

McHugh, AJ: AUTHOR

Abstract

A method of using signature analysis in data compression is disclosed to identify skew edge degradation, symmetry, ringing, noise, and pulse- width problems on digital lines, such as clock lines, data and address lines. In particular, a phase lock technique is disclosed which provides for the ability to phase lock a "carry-up" analyzer to the clock associated with a device under test (DUT) and to compensate for any delay problems which result in coincident edges. A variable frequency portion provides an ability to "tune" for maximum resolution. Thus, in an engineering performance evaluation environment, skews caused by power supply smoothing, temperature variance, early aging, component interaction, etc., can be evaluated. This same capability can be used during No Defect Found (NDF) analysis.

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Increased Resolution When Using Data Compression Techniques

A method of using signature analysis in data compression is disclosed to identify skew edge degradation, symmetry, ringing, noise, and pulse- width problems on digital lines, such as clock lines, data and address lines. In particular, a phase lock technique is disclosed which provides for the ability to phase lock a "carry-up" analyzer to the clock associated with a device under test (DUT) and to compensate for any delay problems which result in coincident edges. A variable frequency portion provides an ability to "tune" for maximum resolution. Thus, in an engineering performance evaluation environment, skews caused by power supply smoothing, temperature variance, early aging, component interaction, etc., can be evaluated. This same capability can be used during No Defect Found (NDF) analysis. In addition, if the compression circuitry were modified to allow selectable capture strobes on both clock transitions, resolution would be doubled with a given strobe/clock frequency. One problem encountered when using signature analysis or data compression as a test and/or diagnostic tool is the following: since the data compression circuitry must be clocked from the DUT to provide synchronization, pulse shape and purity (within a clock cycle) normally cannot be verified. The method according to this invention will provide identification of degraded and/or skewed system lines and, in addition, will allow accurate determination of pulse width, shape, and timing. Referring to Fig. 1, waveform "A" illustrates a desired signal. Waveform "B" represents a clock input to the signature analyzer or data compression circuitry. Waveform "C" represents the actual strobe time of data capture (positive clock transition). The logic level at time "D" is the only recorded indication of the system signal l...