Current Analysis in Circuits Containing a Resistance Modulator

The function of a resistance modulator is to produce in an electric circuit a current which is a copy of an exciting impulse such as speech or light waves. The principal example is the carbon granule telephone transmitter. It is desirable that the electric current be an exact copy of the exciting impulse. There is inherent in such a device however, a distorting effect, for the current copy is produced by reason of Ohm´s law and thus is an inverse function of the modulated resistance and not a true copy of it. The amount of distortion arising from this effect depends upon the electrical constants of the modulator and its associated circuit. The study quantitatively analyzes this distorting effect by two methods in a circuit containing a modulator, a battery, and a resistance for single frequency modulation, and by one of the methods for double frequency modulation. An analysis is also developed for a special test circuit. The study shows that the relation between modulators and circuits is a design problem.