《Agilent Fundamentals of RF and Microwave Noise Figure Measurements》.pdf

Agilent Fundamentals of RF and Microwave Noise Figure Measurements Application Note 57-1 Table of Contents 1. What is Noise Figure? 3 Introduction 3 The importance of noise in communication systems 4 Sources of noise 5 The concept of noise figure 6 Noise figure and noise temperature 7 2. Noise Characteristics of Two-Port Networks 8 The noise figure of multi-stage systems 8 Gain and mismatch 9 Noise parameters 9 The effect of bandwidth 10 3. The Measurement of Noise Figure 11 Noise power linearity 11 Noise sources 11 The Y-factor method 12 The signal generator twice-power method 13 The direct noise measurement method 13 Corrected noise figure and gain 14 Jitter 14 Frequency converters 15 Loss 15 Lo noise 15 Lo leakage 15 Unwanted responses 15 Noise figure measuring instruments 16 Noise figure analyzers 16 Spectrum analyzers 16 Network analyzers 17 Noise parameter test sets 17 Power meters and true-rms voltmeters 17 4. Glossary 18 5. References 28 6. Additional Agilent Resources, Literature and Tools 30 2 Chapter 1. What is Noise Figure? Introduction Modern receiving systems must often process very weak This application note is part of a series about noise measure- signals, but the noise added by the system components tends ment. Much of what is discussed is either material that is to obscure those very weak signals. Sensitivity, bit error ratio common to most noise figure measurements or background (BER) and noi