Noise standards, measurements, and receiver noise definitions

This paper consists of four sections covering 1) basic principles of noise measurement, 2) the switching radiometer, 3) a survey of noise sources, and 4) concepts of noise factor and noise temperature. The first section presents basic formulas used in analyzing radiometers. The second discusses the switching radiometer, briefly tracing its development and usage in the standards field. The third section surveys the development of hot and cold thermal noise sources, noise diodes, and gas-discharge noise generators. The last section presents and discusses the basic definitions of receiver noise performance.