Transmission system for converting a binary information signal to a three level signal

Claim 1

AN INFORMATION TRANSMISSION SYSTEM OF THE TYPE IN WHICH INFORMATION TO BE TRANSMITTED IS IN THE FORM OF A CODED SERIES OF COMMON AMPLITUDE PULSES WHICH OCCUR ONLY AT CLOCK INSTANTS, SAID SYSTEM COMPRISING A SOURCE OF SAID SERIES OF PULSES, MEANS FOR CONVERTING SAID SERIES OF PULSES TO A CODED SIGNAL HAVING SEPARATELY OCCURRING FIRST AND SECOND LEVELS CORRESPONDING TO THE OCCURRENCE OF PULSES IN SAID SERIES OF PULSES AND A THIRD INTERMEDIATE LEVEL CORRESPONDING TO THE ABSENCE OF PULSES IN SAID SERIES OF PULSES AT SAID CLOCK INSTANTS, SAID CONVERTING MEANS COMPRISING MEANS RESPONSIVE TO EACH ABSENCE OF A PULSE OF SAID SERIES OF PULSES AT A CLOCK INSTANT IMMEDIATELY FOLLOWING THE OCCURRENCE OF A PULSE AT A CLOCK INSTANT FOR SHIFTING THE LEVEL OF SAID SIGNAL AT THE NEXT OCCURRENCE OF A PULSE OF SAID PULSE SERIES AT A CLOCK INSTANT TO THE ONE OF SAID FIRST AND SECOND LEVELS DIFFERENT THAN THE LEVEL IT HAD IMMEDIATELY PRIOR TO THE INSTANT AT WHICH NO PULSE OCCURRED, AND MEANS FOR RESHAPING SAID CODED SIGNALS TO PRODUCE AN OUTPUT SIGNAL, SAID RESHAPING MEANS COMPRISING A COMPRESSION CIRCUIT HAVING A PARABOLIC RESPONSE CHARACTERISTIC WHEREBY ONLY THE TRANSIENT PARTS OF SAID CODED SIGNALS ARE TRANSFORMED TO SINUSOIDAL FORM OF A FREQUENCY LOWER THAN THE REPETITION FREQUENCY OF SAID CLOCK INSTANTS.