Allan variance phase noise

1. What is Allan variance and how is it used?
2. Why do we use Allan variance?
3. How do you calculate Allan deviation?
4. What is meant by phase noise?

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.

Why do we use Allan variance?

Allan deviation is widely used for plots (conventionally in log–log format) and presentation of numbers. It is preferred, as it gives the relative amplitude stability, allowing ease of comparison with other sources of errors.

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.

What is meant by phase noise?

Phase noise is defined as the ratio of noise power at a given offset frequency to the carrier power. From: Principles and Applications of RF/Microwave in Healthcare and Biosensing, 2017.