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Displaying 26 - 50 of 93

A Precision Millimeter-Wave Modulated-Signal Source

June 6, 2013
Author(s)
Catherine A. Remley, Paul D. Hale, Dylan F. Williams, Chih-Ming Wang
We develop and characterize a modulated-signal source for use at millimeter-wave frequencies. Components within the source are phase locked by a 10 GHz reference source to minimize drift and improve synchronization. The complex frequency response of the

Sequential Estimation of Timebase Corrections for an Arbitrarily Long Waveform

October 1, 2012
Author(s)
Chih-Ming Wang, Paul D. Hale, Jeffrey A. Jargon, Dylan F. Williams, Catherine A. Remley
We present a procedure for correcting the timebase distortion and jitter of temporal waveforms of arbitrary lengths. This is achieved by estimating the timebase distortion and jitter sequentially with overlapping measurements and using the information in

Traceability of high-speed electrical waveforms at NIST, NPL, and PTB

July 6, 2012
Author(s)
Paul D. Hale, Dylan F. Williams, Andrew M. Dienstfrey, Chih-Ming Wang, Jeffrey A. Jargon, David Humphreys, Matthew Harper, Heiko Fuser, Mark Bieler
Instruments for measuring high-speed waveforms typically require calibration to obtain accurate results. The national metrology institutes of the United States of America, the United Kingdom, and Germany offer measurement services based on electro-optic

Pivotal Methods in the Propagation of Distributions

April 24, 2012
Author(s)
Chih-Ming Wang, Jan Hannig, Hariharan K. Iyer
We propose a method for assigning a probability distribution to an input quantity. The distribution is used in the Monte Carlo method for uncertainty evaluation. The proposed method provides an alternative to other methods, such as the principle of maximum

Fiducial Prediction Intervals

February 18, 2012
Author(s)
Chih-Ming Wang, Jan Hannig, Hariharan K. Iyer
This paper presents an approach for constructing prediction intervals for any given distribution. The approach is based on the principle of fiducial inference. We use several examples, including the normal, binomial, gamma, and Weibull distributions, to

A statistical study of de-embedding applied to eye diagram analysis

February 1, 2012
Author(s)
Paul D. Hale, Jeffrey A. Jargon, Chih-Ming Wang, Brett Grossman, Matthew Claudius, Jose Torres, Andrew M. Dienstfrey, Dylan F. Williams
We describe a stable method for calibrating digital waveforms and eye diagrams using the measurement system response function and its regularized inverse. The function describing the system response includes the response of the oscilloscope and any

On Non-Linear Estimation of a Measurand

November 7, 2011
Author(s)
Chih-Ming Wang, Hariharan K. Iyer
We consider an estimation problem described in the Guide to the Expression of Uncertainty in Measurement (GUM). The problem is concerned with estimating a measurand that is a non-linear function of input quantities. The GUM describes two methods for

On Multiple-Method Studies

October 4, 2010
Author(s)
Chih-Ming Wang, Hariharan K. Iyer
In this paper we review statistical models that describe measurements from a multiple-method study such as in the development of a reference material. We also review requirements for the so-called GUM compliance as this appears to be an important criterion

Use of Electronic Calibration Units for Vector-Network-Analyzer Verification

July 30, 2010
Author(s)
Dylan F. Williams, Arkadiusz C. Lewandowski, Denis X. LeGolvan, Ronald A. Ginley, Chih-Ming Wang, Jolene D. Splett
We present measurements indicating that electronic calibration units are stable enough to be used in place of mechanical vector-network-analyzer verification artifacts. This enables a new fully automated approach to verifying microwave vector-network

On interchangeability of two laboratories

June 18, 2010
Author(s)
Chih-Ming Wang, Hariharan K. Iyer
This paper proposes a measure for assessing the degree of equivalence between the two laboratories in a key comparison. The measure is called asymmetric degree of interchangeability. It is asymmetric since, based on this measure, a laboratory may be

Why are we concerned with large covariance matrices?

June 1, 2010
Author(s)
Paul D. Hale, Andrew M. Dienstfrey, Chih-Ming Wang
In order to promote discussion, we outline the two different paradigms for propagating uncertainties from the various waveform measurement impairments to the waveform parameters. The first method propagates uncertainty from the impairments directly to a

Identifying RF Identification Cards from Measurements of Resonance and Carrier Harmonics

May 27, 2010
Author(s)
Henry Romero, Kate Remley, Dylan Williams, Chih-Ming Wang, Timothy X. Brown
We show that careful measurements of the unloaded resonant frequency and quality factor of radio frequency identification proximity cards allow identification of different card models and, for the set of cards we studied, identification with minimal error

Uncertainty of timebase corrections

October 1, 2009
Author(s)
Chih-Ming Wang, Paul D. Hale, Dylan F. Williams
We develop a covariance matrix describing the uncertainty of a new timebase for waveform measurements determined with the National Institute of Standards and Technology's timebase correction algorithm. This covariance matrix is used with covariance

Uncertainty calculation for spectral-responsivity measurements

September 1, 2009
Author(s)
John H. Lehman, Chih-Ming Wang, Marla L. Dowell, Joshua A. Hadler
This paper discusses a procedure for measuring the absolute spectral responsivity of optical-fiber power meters and computation of the calibration uncertainty. The procedure reconciles measurement results associated with a monochromator-based measurement

Calculation of pulse parameters and propagation of uncertainty

March 1, 2009
Author(s)
Paul D. Hale, Chih-Ming Wang
The fundamental starting point for the analysis of all two-state waveforms is the determination of the low- and highstate levels. This is a two-step process. First, the data are grouped into points belonging to each state, and second, the value of each

Three Statistical Paradigms for the Assessment and Interpretation of Measurement Uncertainty

January 12, 2009
Author(s)
William F. Guthrie, Hung-Kung Liu, Andrew L. Rukhin, Blaza Toman, Chih-Ming Wang, Nien F. Zhang
The goals of this chapter are to present different approaches to uncertainty assessment from a statistical point of view and to relate them to the methods that are currently being used in metrology or are being developed within the metrology community. The

Fiducial Intervals for the Magnitude of a Complex-Valued Quantity

December 19, 2008
Author(s)
Chih-Ming Wang, Hariharan K. Iyer
This paper discusses a fiducial approach for constructing uncertainty intervals for the distance between k normal means and the origin. When k=2 this distance is equivalent to the magnitude of a complex-valued quantity. Uncertainty intervals for the

A robust algorithm for eye-diagram analysis

November 1, 2008
Author(s)
Jeffrey A. Jargon, Paul D. Hale, Chih-Ming Wang
We present a new method for analyzing eye diagrams that always provides a unique solution by making use of a robust, least-median-of-squares (LMS) location estimator. In contrast to commonly used histogram techniques, the LMS procedure is insensitive to

Charpy Machine Verification: Limits and Uncertainty

September 1, 2008
Author(s)
Jolene Splett, Christopher N. McCowan, Chih-Ming Wang
The purpose of this document is to clarify some issues pertaining to uncertainty statements and the ASTM E 23 limits used in the Charpy machine verification program. We explain some of the distributional subtleties associated with uncertainty and