Anti-side tone telephone sets

It is shown that the variation of side tone in an anti-side tone set is not under the control of the designer except in so far as the line impedance on which the set is to give optimum performance may be regarded as arbitrary, and to the extent that the different types of anti-side tone circuits give different characteristic variations of the no-side tone line impedance with frequency. The definitions of the general symbols and the derivations of the formulaelig used are contained in Appendices.