Arrangements for controlling generators showing an adjustable conductivity

Claim 1

IN COMBINATION WITH A MAIN POLYPHASE GENERATOR OF AN ADJUSTABLE CONDUCTIVITY AND EFFECTIVE TO PRODUCE SIGNALS OF ADJUSTABLE AMPLITUDE AND ADJUSTABLE FIRST FREQUENCY, A COMMON REFERENCE GENERATOR ADAPTED TO PRODUCE ONE REFERENCE SIGNAL AT A PREDETERMINED SECOND FREQUENCY MUCH HIGHER THAN SAID FIRST FREQUENCY, THE CURVE REPRESENTING THE VARIATION WITH RESPECT TO TIME OF THE REFERENCE SIGNAL HAVING THE SAME SHAPE AS THE CORRESPONDING CURVE REPRESENTING THE VARIATION WITH RESPECT TO TIME OF THE SIGNAL TO BE PRODUCED BY THE MAIN GENERATOR, MEANS COMPARING, AT A COMPARISON FREQUENCY DIFFERENT FROM THE FREQUENCY OF THE REFERNCE SIGNAL, THE SUCCESSIVE INSTANTANEOUS VALUES OF THE REFERENCE SIGNAL WITH THE CORRESPONDING INSTANTANEOUS VALUES OF THE MAIN GENERATOR SIGNALS IN EACH PHASE, MEANS CONTROLLED BY SAID COMPARING MEANS AND CONTROLLING THE CONDUCTIVITY OF THE MAIN GENERATOR TO MAINTAIN THE MAIN GENERATOR SIGNALS IN THE CORRESPONDING PHASE SUBSTANTIALLY PROPORTIONAL TO SAID SUCCESSIVE INSTANTANEOUS VALUES OF THE REFERENCE SIGNAL, THE FREQUENCY OF THE MAIN GENERATOR SIGNALS BEING EQUAL TO THE DIFFERENCE BETWEEN THE FREQUENCY OF THE REFERENCE SIGNAL IN ONE PHASE AND THAT OF A FREQUENCY SELECTED FROM THE FUNDAMENTAL AND HARMONIC FREQUENCIES OF THE COMPARISON FREQUENCY.