Specification and Measurement of Receiver Sensitivity at the Higher Frequencies

The paper discusses the influence of receiver noise on sensitivity performance at higher frequencies. Established I.R.E. standard definitions and test methods do not give proper emphasis to the important factor of noise. A practice recently adopted of specifying sensitivity in terms of noise figure is reviewed, and there is introduced a method, not yet commonly used, of measuring this quantity with a diode noise generator. Noise figure, however, is not an adequate specification of sensitivity, for it ignores over-all gain. To include both factors, a proposed combined sensitivity figure is presented. The alternatives for specifying sensitivity in terms of voltage or power are compared, and the concept of available power is explained.