This publication pertains to wide-band transformers, transmitting power of equal to or more than 100 W1. Guides to application and test procedures are included. Appendices contain certain precautions and recommended practices. Provision is made for including data for use in the design of feedback amplifiers and control networks or other circuits in which knowledge of the transformer amplitude- and phasefrequency response is needed by the system designer. These transformers are required to transform voltage within specified tolerances of amplitude and phase when operating between specified impedances