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Search Publications by: David A. Howe (Assoc)

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Displaying 1 - 25 of 123

Characterizing Frequency Stability Measurements having Multiple Data Gaps

February 2, 2022
Author(s)
David A. Howe, Noah Schlossberger
Time series measurements with data gaps (dead times) prevent accurate computations of frequency variances such as the Allan variance (AVAR) and its square-root ADEV. To extract frequency distributions, data must be sequentially ordered and equally spaced

Time-series Imputation Algorithm

November 5, 2021
Author(s)
David A. Howe, Chloe Champagne
Statistical imputation is a field of study that attempts to fill missing data. It is commonly applied to population statistics whose data have no correlation with running time. For a time series, data is typically analyzed using the autocorrelation, the

PSCR 2017 Stakeholder Conference Presentation Materials -- Day 3

October 16, 2018
Author(s)
Dereck R. Orr, Richard A. Rouil, Jeremy E. Benson, David W. Griffith, Fidel Liberal, Robert Escalle, Sonim Technologies, Richard Lau, Vencore Labs, Paul Sutton, Software Radio Systems LTD, Sumit Roy, Sean Sangodoyin, David A. Howe, Fabio C. Da Silva, Alicia Evangelista, Yet2, Brienne Engel, Yet2, John S. Garofolo
This document is a compilation of the slides presented during Day 3 of the 2017 Public Safety Communications Research Program's (PSCR) Annual Stakeholder Conference. Day 3 topics include PSCR research plans and results for Mission Critical Voice, Indoor

Prospects for Magnetic Field Communications and Location Using Quantum Sensors

December 14, 2017
Author(s)
Vladislav P. Gerginov, Fabio C. Da Silva, David A. Howe
Signal attenuation limits the operating range in wireless communications and location. To solve the reduced range problem, one can use low-frequency signals in combination with magnetic sensing. We propose the use of an optically-pumped magnetometer as a

Measurement of AM-to-PM Conversion in a Quartz-MEMS Resonator

May 9, 2016
Author(s)
Craig W. Nelson, Archita Hati, David A. Howe
This work investigates the new aspects of the non-linear response in a quartz-MEMS resonator at 635 MHz. We characterize its major cause of AM-to-PM conversion as a function of power and drive frequency; this is important in developing noise compensation

Power Splitter Thermal Noise Correlations in Cross-spectrum Noise Measurements

May 9, 2016
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
We discuss collapse of the cross-spectrum phase noise measurement of thermally-limited oscillator due to anti-correlated thermal noise of the Wilkinson power splitter. We also examine effect of thermal noise of various resistive power splitters on such

Practical Evaluation of a 50 km Fiber Link Utilizing a Commercial Modem

May 9, 2016
Author(s)
Corey A. Barnes, Archita Hati, Craig W. Nelson, David A. Howe
We evaluate the stability of two-way time and frequency transfer over a 50 km fiber optic link established using a commercially available fiber optic modem. For this evaluation we report the residual phase noise, total Allan deviation, total time deviation

Cross-spectral Collapse from Anti-correlated Thermal Noise in Power Splitters

April 4, 2016
Author(s)
Craig Nelson, Archita Hati, David A. Howe
We discuss the cross-spectral collapse due to anti-correlated thermal noise that originates from the common-mode power divider (splitter) in a cross-spectrum noise measurement system. We studied this effect for different power splitters and discuss its

Oscillator PM-noise reduction from correlated AM-noise

March 11, 2016
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
We demonstrate a novel technique for reducing the phase modulation (PM) noise of an oscillator in steady state as well as under vibration. It utilizes correlation between PM noise and amplitude modulation (AM) noise that can originate from the oscillator's

Cross-spectrum Measurement of Thermal-noise Limited Oscillators

March 1, 2016
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
Cross-spectrum analysis is a commonly-used technique for the detection of phase and amplitude noise of a signal in the presence of interfering noise. It extracts the desired correlated noise from two time series which also contain uncorrelated interfering

Optical-to-RF Frequency Synthesis: Application Priorities for Ultra-low Phase Noise

October 18, 2015
Author(s)
David A. Howe, Archita Hati, Craig W. Nelson, Lora L. Nugent-Glandorf
We describe operational challenges and progress of optical frequency-comb dividers (OFDs) that synthesize RF signals from the optical domain. Our priorities include: (1) ultra-low phase-noise, (2) continuous operation, and (3) broadly low Allan deviation.

PM Noise Measurement at W-Band

December 12, 2014
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
We present improved performance for a 92 - 96 GHz cross-spectrum phase modulated (PM) noise measurement system previously reported. The system is principally designed to measure amplifiers in pulsed mode with a duty cycle of 10% to 100% (CW) at a given

A 40 GHz Air-Dielectric Cavity Oscillator with Low Phase Modulation

September 1, 2014
Author(s)
Archita Hati, Craig W. Nelson, Billy F. Riddle, David A. Howe
We describe the design of a low-phase modulated (PM) noise, 40 GHz oscillator that uses a conventional air-dielectric cavity resonator as a frequency discriminator to improve the PM noise of a commercial 10 GHz dielectric resonator oscillator (DRO)

Reducing oscillator PM noise from AM-PM noise correlaiton

August 14, 2014
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
We present a new scheme for improving the phase modulated (PM) noise of an oscillator from correlation between amplitude modulated (AM) and PM noise. Experimental results of this correlation effect are presented. An improvement of almost 10 dB in the PM

Collapse of the Cross-spectral Function

May 22, 2014
Author(s)
Craig W. Nelson, Archita Hati, David A. Howe
Cross-spectral analysis is a mathematical tool for extracting the power spectral density of a correlated signal from two time series in the presence of uncorrelated interfering signals. We demonstrate and explain a set of amplitude and phase conditions

Correlation Measurements between PM and AM Noise in Oscillators

May 22, 2014
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
We discuss techniques for measuring the correlation between phase modulated (PM) and amplitude modulated (AM) noise in an oscillator and report results of such correlation in a few selected oscillators of similar size, weight, power consumption and

A collapse of the cross-spectral function in phase noise metrology

February 25, 2014
Author(s)
Craig W. Nelson, Archita Hati, David A. Howe
Cross-spectral analysis is a mathematical tool for extracting the power spectral density of a correlated signal from two time series in the presence of uncorrelated interfering signals. We demonstrate and explain a set of conditions where the detection of

Phase inversion and collapse of the cross-spectral function

December 5, 2013
Author(s)
Craig W. Nelson, Archita Hati, David A. Howe
Cross-spectral analysis is a mathematical tool for extracting the power spectral density of a correlated signal from two time series in the presence of uncorrelated interfering signals. We demonstrate and explain a set of conditions where the detection of

State-of-the-Art RF Signal Generation From Optical Frequency Division

September 2, 2013
Author(s)
Archita Hati, Craig W. Nelson, Corey A. Barnes, Danielle G. Lirette, Tara M. Fortier, Franklyn J. Quinlan, Jason A. DeSalvo, Andrew D. Ludlow, Till P. Rosenband, Scott A. Diddams, David A. Howe
We present the design of a novel, ultra-low phase-noise frequency synthesizer implemented with extremely low noise regenerative frequency dividers. This synthesizer generates eight outputs viz. 1.6 GHz, 320 MHz, 160 MHz, 80 MHz, 40 MHz, 20 MHz, 10 MHz and

A One-Kilogram Quartz Resonator as a Mass Standard

February 1, 2013
Author(s)
David A. Howe, J Vig
The unit of mass, the kilogram, is the last remaining SI base unit defined by an artifact” [1]. This artifact, the primary mass standard, suffers from long term instabilities that are neither well understood, nor easily monitored [2]. A mass standard

Phase-Noise Measurement System for the Terahertz-Band

November 30, 2012
Author(s)
Jason A. DeSalvo, Archita Hati, Craig W. Nelson, David A. Howe
We present initial phase noise measurements in support of terahertz electronics, in the frequency range generally regarded as 0.1 to 10 THz. Using digital phase noise measurement techniques and an even-harmonic mixer, we achieve a phase noise measurement

Ultra-low noise regenerative frequency divider

November 11, 2012
Author(s)
Archita Hati, Craig W. Nelson, Corey A. Barnes, Danielle G. Lirette, Jason A. DeSalvo, David A. Howe
We designed ultra-low noise regenerative divider-by-2 circuits that operate at input frequencies of 20 MHz and 10 MHz. We achieved residual output-referred single-sideband phase noise below -162 dBc/Hz at 10 Hz offset for a single divider at these

A Sub-Sampling Digital PM/AM Noise Measurement System

September 1, 2012
Author(s)
Craig W. Nelson, David A. Howe
A digital phase/amplitude modulation (PM/AM) noise measurement systems (DNMS) implementing field progammable gate array (FPGA) based digital down converters (DDCs), and 250 MHz analog to digital converters (ADCs) is reported. Measurements in the first