1.2 How PPM’s work 1.2 How PPM’s work 1 Introduction 1.3 Overview of magnetometer 1.3 Overview of magnetometer 1.2 How PPM’s work 1.1 The proton precession magnetometer 1.1 The proton precession magnetometer 1.3 Overview of magnetometer 1 Introduction 1.1 The proton precession magnetometer 1 Introduction