Carrier current signalling system using quaternary modulation

Claim 1

IN AN ELECTRICAL SIGNALLING SYSTEM FOR THE TRANSMISSION OF A SERIES OF BINARY INFORMATION ELEMENTS BY QUATERNARY PHASE MODULATION, A FIRST TOGGLE, MEANS FOR SUPPLYING THE BINARY INFORMATION TO EFFECT THE SELECTIVE OPERATION OF SAID FIRST TOGGLE, A SECOND TOGGLE, MEANS FOR OPERATING SAID SECOND TOGGLE FROM SAID FIRST TOGGLE SO AS TO CONSTITUTE A SINGLE-STAGE SHIFT REGISTER, A THIRD TOGGLE, A FOURTH TOGGLE MEANS FOR OPERATING SAID THIRD AND FOURTH TOGGLES UNDER THE JOINT CONTROL OF SAID FIRST AND SECOND TOGGLES, A SOURCE OF CARRIER CURRENT OF PREDETERMINED FREQUENCY, A PHASE MODULATOR, MEANS FOR SUPPLYING CARRIER CURRENT FROM SAID SOURCE TO SAID MODULATOR, A 90* PHASE SHIFTER, MEANS FOR SUPPLYING CARRIER CURRENT FROM SAID SOURCE TO SAID MODULATOR BY WAY OF SAID PHASE SHIFTER, AND MEANS FOR CONTROLLING SAID MODULATOR JOINTLY FROM SAID THIRD AND FOURTH TOGGLES WHEREBY THE PHASE CHANGE IN THE OUTPUT FROM SAID MODULATOR BETWEEN SUCCESSIVE ELEMENTS VARIES IN ACCORDANCE WITH THE VALUE OF SUCCESSIVE PAIRS OF ELEMENTS IN SAID BINARY INFORMATION.