Characterization of frequency stability

Barnes, James A.

doi:10.6028/nbs.tn.394

Cited by 371 publications

(197 citation statements)

References 15 publications

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“…5a. Secondly, to evaluate clock stability over long durations i.e., t 1 seconds, we use Allan variance, which is a measure of nominal fractional frequency drift [8]. Following [71,73], the stability requirement on the clock and define the coherence time τ c , such that the RMS phase error of the clock remains less than 1 radian…”

Section: Clocksmentioning

confidence: 99%

Space-based aperture array for ultra-long wavelength radio astronomy

et al. 2015

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The past decade has seen the advent of various radio astronomy arrays, particularly for low-frequency observations below 100 MHz. These developments have been primarily driven by interesting and fundamental scientific questions, such as studying the dark ages and epoch of re-ionization, by detecting the highly redshifted 21 cm line emission. However, Earth-based radio astronomy observations at frequencies below 30 MHz are severely restricted due to man-made interference, ionospheric distortion and almost complete non-transparency of the ionosphere below 10 MHz. Therefore, this narrow spectral band remains possibly the last unexplored frequency range in radio astronomy. A straightforward solution to study the universe at these frequencies is to deploy a space-based antenna array far away from Earths' ionosphere. In the past, such space-based radio astronomy studies were principally limited by technology and computing resources, however current processing and communication trends indicate otherwise. Furthermore, successful space-based missions which mapped the sky in this frequency regime, such as the lunar orbiter RAE-2, were restricted by very poor spatial resolution. Recently concluded studies, such as DARIS (Disturbuted Aperture Array for Radio Astronomy In Space) have shown the ready feasibility of a 9 satellite constellation using off the shelf components. The aim of this article is to discuss the current trends and technologies towards the feasibility of a space-based aperture array for astronomical observations in the Ultra-Long Wavelength (ULW) regime of greater than 10 m i.e., below 30 MHz. We briefly present the achievable science cases, and discuss the system design for selected scenarios such as extra-galactic surveys. An extensive discussion is presented on various sub-systems of the potential satellite array, such as radio astronomical antenna design, the on-board signal processing, communication architectures and joint space-time estimation of the satellite network. In light of a scalable array and to avert single point of failure, we propose both centralized and distributed solutions for the ULW space-based array. We highlight the benefits of various deployment locations and summarize the technological challenges for future space-based radio arrays.

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Section: Clocksmentioning

confidence: 99%

Space-based aperture array for ultra-long wavelength radio astronomy

et al. 2015

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“…(12) The root of (12) is the Allan deviation. In [5], the relationship between the Fourier-domain representation of S y (f m ) and time-domain Allan variance was determined and is given by: .…”

Section: B Application Of the Model And A Mathematical Pathologymentioning

confidence: 99%

On modern and historical short-term frequency stability metrics for frequency sources

McCorquodale¹,

Brown

2009

2009 IEEE International Frequency Control Symposium Joint With the 22nd European Frequency and Time Forum

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Abstract-Modern frequency stability metrics employed in industry are discussed within the context of the historical development of the Allan variance. It is shown that phase noise and the first and second jitter differences are often reported in lieu of the Allan variance for frequency sources utilized in consumer electronics. This inconsistency between the historical and modern treatment of frequency stability is addressed through the presentation of analytical relationships and bounds for these common metrics. The presented expressions are compared with experimental results where good agreement is found while employing several different measurement approaches. The clear requirement for standardized metrology is motivated.

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“…Its characterization and measurement are, therefore, of great significance in application. The concept and characterization of phase noise have been introduced in detail [1]. Demir and Roychowdhury [2] analyzed the effect of orthogonally decomposed perturbations on phase noise, studied a unifying theory and numerical methods for practical characterization of phase noise in the oscillator, and used several different kinds of perturbations for simulation.…”

Section: Introductionmentioning

confidence: 99%

A New Algorithm for Eliminating the Frequency Difference in Phase Noise Measurement of the Microwave Signal

Chen

Zhang²,

Wang³

2012

PIER M

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Abstract-The frequency difference between signal-under-test and reference signal in phase demodulation will affect the result of the actual phase noise measurement. In order to eliminate the effect, an algorithm for both eliminating the frequency difference and extracting the phase noise of the signal-under-test is presented. Simulation and experiment results show that this algorithm is effective. By using the algorithm in our experiment, the noise floor of the measurement system is improved by 10.1 dB and 9.3 dB, respectively, and the measurement precision is improved from 90.03% to 96.31%. In addition, the use of this algorithm can lower the requirement on the frequency precision of reference source and reduce the cost of measurement system.

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Characterization of frequency stability

Cited by 371 publications

References 15 publications

Space-based aperture array for ultra-long wavelength radio astronomy

Space-based aperture array for ultra-long wavelength radio astronomy

On modern and historical short-term frequency stability metrics for frequency sources

A New Algorithm for Eliminating the Frequency Difference in Phase Noise Measurement of the Microwave Signal

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