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Search Publications by: David A. Howe (Assoc)

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Displaying 76 - 100 of 206

Optical Fiber Vibration and Acceleration Model

May 29, 2007
Author(s)
Neil Ashby, David A. Howe, Jennifer A. Taylor, Archita Hati, Craig W. Nelson
We derive expressions for the group velocities of transverse electric and transverse magnetic electromagnetic waves in a stretched single-mode fiber. Stretching can occur either as a result of temperature changes of the spool on which the fiber is wound

Phase Noise of X-band Oscillator and Amplifier Technologies Compared

May 29, 2007
Author(s)
David A. Howe, Archita Hati
We compare best-in-class phase noise of different technologies of oscillators and amplifiers at X-band. Results are presented based on recent measurements at NIST. In particular, comparisons are made between mature technologies of multiplied quartz

Preliminary study on the vibration sensitivity performance of microwave components

May 29, 2007
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe, Neil Ashby, Jennifer A. Taylor, Kai Hudek, C. Hay, David Seidel, D. Eliyahu
Vibration sensitivity is an important specification for oscillators on mobile systems, Unmanned Aerial Vehicles (UAVs) etc. These systems must provide superior performance when subject to severe environmental conditions. Electronic oscillators often can

TheoH and Allan Deviation as Power-Law Noise Estimators

February 1, 2007
Author(s)
Jennifer A. Taylor, David A. Howe
A spectral interpretation using the frequency response of the Allan Variance is used to determine slopes of f α noise, commonly called ''power-law noise.'' This paper shows that TheoH provides significantly better determination of f α noise slopes at long

Merits of PM Noise Measurement over Noise Figure: A Study at Microwave Frequencies

October 1, 2006
Author(s)
Archita Hati, David A. Howe, Fred L. Walls, D. Walker
This paper addresses two issues: (i) it compares the usefulness of phase-modulation (PM) noise measurements vs. noise figure (NF) measurements in characterizing the merit of an amplifier, and (ii) it reconciles a general misunderstanding in using ¿174 dBc

Comparison of AM noise in commercial amplifiers and oscillators at X-band

June 5, 2006
Author(s)
Archita Hati, David A. Howe, Craig Nelson
In this paper we discuss the importance of amplitude modulated (AM) noise. AM noise is often neglected and considered as a minor problem. However, AM noise can become very important in high performance systems that require ultra-low phase modulated (PM)

Low Phase Noise Amplifier and Oscillator using Feed-Forward Technique at 10 GHz

June 5, 2006
Author(s)
Archita Hati, Craig Nelson, David A. Howe
We discuss the performance of a feed-forward amplifier (FFA) at 10 GHz. The feed-forward method is primarily used to suppress intermodulation distortion in amplifiers to suppress up-converted near-DC noise. The main amplifier in this configuration is a low

Relativity and Timing in X-ray Pulsar Navigation

June 5, 2006
Author(s)
Neil Ashby, David A. Howe
XNAV is a technology demonstration that will use photons from X-ray pulsars for navigation and spacecraft attitude determination. This paper summarizes relativistic effects in the context of XNAV. It also characterizes the primary task in the time domain

TheoH Bias-removal Method

June 5, 2006
Author(s)
David A. Howe, Jennifer A. Taylor, Tiffany Tassett
A version of Theo1 variance, called TheoBR variance (BR for ''bias-removed'' relative to the Allan variance), is constructed. This relative bias correction is applied over a range of the longest-recommended Allan tau values for a given data run. The oH

Comparison of AM Noise in Commercial Amplifiers and Oscillators at X-Band

June 1, 2006
Author(s)
Archita Hati, David A. Howe, Craig W. Nelson
In this paper we discuss the importance of amplitude-modulated (AM) noise. AM noise is often neglected and considered a s a minor problem. However, AM noise can become very important in high performance systems that require ultra-low phase-modultaed (PM)