Synthesizer of multifrequency code signals

摘要: Synthesizer of multifrequency signals for telephone sets, each signal being formed by two concomitant sinusoidal different basic frequencies, said frequencies forming pairs respectively corresponding to the decimal digits and sub-multiples a common clock frequency. The are pulse trains whose repetition rate varies steppedly in function time following manner. period sine is divided into p parts amplitude taken from tangent negative peaks curve equidistributed values argument 2πi/p, i varying l p, approximated values. periods having frequences intervals during these intervals, train generator operated such way that its be proportional