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The total deviation approach to long-term characterization of frequency stability
1Nat. Inst. of Stand. and Technol., Boulder, CO.
Summary
Total variance (Totvar) and its square root, total deviation (Totdev), advance frequency stability estimation. Totdev offers improved confidence and noise analysis for oscillators at long averaging times.
Area of Science:
- Metrology
- Signal Processing
- Physics
Background:
- Conventional Allan variance is the standard for long-term frequency stability.
- Estimating oscillator noise at long averaging times (tau) is challenging.
- Existing methods have limitations in accuracy and sensitivity.
Purpose of the Study:
- Introduce Total Variance (Totvar) and Total Deviation (Totdev) as new estimators for frequency stability.
- Demonstrate Totdev's advantages over traditional methods for long-term analysis.
- Provide a unified framework for frequency stability analysis.
Main Methods:
- Development of Total Variance (Totvar) and Total Deviation (Totdev) definitions.
- Application of data extrapolation and smoothing concepts.
- Analysis of noise levels and types in FM oscillators.
- Comparison with Allan deviation for stability plots and confidence intervals.
Main Results:
- Totdev efficiently extracts broadband FM oscillator noise at long tau.
- Totdev offers improved confidence in long-term frequency stability estimation.
- Totdev shows lower sensitivity to linear frequency drift removal.
- Exact decomposition of frequency residual sample variance is achieved.
Conclusions:
- Totdev represents a significant advancement in estimating long-term frequency stability.
- It provides a more robust and accurate method for oscillator noise characterization.
- Totdev unifies frequency stability statistics with standard deviation through exact decomposition.
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