Oscillator Design - Part IV — Lesson 4

This lesson covers the concept of phase noise in RF transceiver design, focusing on the unit used to measure phase noise, DBC per Hz. It delves into the one-port view of the oscillator, discussing the role of the RLC resonator and the active component that generates negative resistance. The lesson also explains the concept of noise current density and how it contributes to phase noise. It further explores the lessons model of phase noise, highlighting the importance of understanding the third order slope, second order slope, and the constant throughout the frequency as thermal noise. The lesson concludes by discussing the limitations of the lessons model and introducing the linear time variant model as a more accurate alternative.

Video Highlights

00:25 - Explanation of phase noise
12:59 - Issues with the Lessons model and roles of linearity
17:02 - Effect of impulse current on LC tank
24:14 - Discussion on the conversion of phase to voltage
35:36 - Concept of reciprocal mixing in phase noise
38:57 - GSM cellular telephone standard and its requirements for phase noise

Key Takeaways

- Phase noise in RF trans design is measured in DBC per Hz.
- The RLC resonator and the active component that generates negative resistance play crucial roles in the one-port view of the oscillator.
- Noise current density contributes to phase noise.
- The lessons model of phase noise is based on understanding the third order slope, second order slope, and the constant throughout the frequency as thermal noise.
- The linear time variant model is a more accurate alternative to the lessons model, as it considers nonlinearity, a fundamental property of real oscillators.