Python allan variance

1. What is Allan variance and how is it used?
2. How do you calculate Allan deviation?
3. How do you read Allan variance?

What is Allan variance and how is it used?

Allan variance is a statistical analysis tool for identifying various noise types that exist in a signal. Developed in the mid-1960s, the Allan variance was used to measure the frequency stability of precision oscillators. Later, this technique was applied to other areas as well.

How do you calculate Allan deviation?

Standard deviation is the square root of variance. So to get Allan deviation from Allan variance, we just take the square root of every variance measure we calculated above.

How do you read Allan variance?

An Allan deviation of 1.3×10−9 at observation time 1 s (i.e. τ = 1 s) should be interpreted as there being an instability in frequency between two observations a second apart with a relative root mean square (RMS) value of 1.3×10−9. For a 10-MHz clock, this would be equivalent to 13 mHz RMS movement.