Statistical Circuit Design: Linear Circuits and Statistical Design

In the Bell System, the origin of interest in the statistical design of linear circuits is lost in history. It could have been no later than the earliest planning for repeaters and filters for carrier systems, as no such system is possible without precise control of frequency and loss characteristics. As the total installed cost of a carrier system is always much greater than the cost of the design effort, use of the most advanced design procedures and techniques known, including statistical methods, has always been justified. The selection of tolerances for component parts is one of the many topics which is under the control of the designer. He must select values and specify manufacturing tests so as not to increase costs either by paying a premium for unnecessarily precise elements or by rejecting correctly assembled networks in production. In the past, the tools that have been available to the designer to assist in the determination of tolerance limits have ranged from primitive to highly sophis1149