Abstract
This paper develops an intuitive understanding of the meaning and implications of Middleton's canonical formula for Class A noise. The probability density function (pdf) for noise in decibels is derived, and each of the parameters has a clear physical meaning. The effects of parameter variation on the pdf are shown graphically. The canonical Class A formula predicts that the interdecile range of non- Gaussian noise (structured interference) is less than about 30 dB. A simple scenario that produces canonical Class A interference is described. The limited interdecile range of the interference forces the interfering sources in the simple scenario to be located within a limited range of distances. Thus the strictly canonical formula for Class A noise is inadequate for modeling many physical situations.