Phase shift data transmission system with phase-coherent data recovery

Claim 1

A COMMUNICATION SYSTEM FOR TRANSMITTING DIGITAL DATA COMPRISING MEANS TO MODULATE A CARRIER WITH DATA IN THE FORM OF DIGITIAL BITS AND WITH A TONE SIGNAL HAVING A REPETITION RATE EQUEL TO THE DATA BIT RATE TO PRODUCE A DOUBLE SIDEBAND CARRIER SUPPRESSED SIGNAL, MEANS TO RECEIVE SAID MODULATED CARRIER, A DEMODULATOR, A LOCAL OSCILLATOR MEANS TO SUPPLY A SIGNAL AT THE CARRIER FREQUENCY, SAID LOCAL OSCILLATOR BEING CAPABLE OF ASSUMING ZERO AND 180* PHASE POSITIONS, MEANS TO APPLY THE CARRIER SIGNAL TO SAID DEMODULATOR TO RECOVER THE DATE BITS AND THE TONE SIGNAL, MEANS TO CONTROL THE LOCAL OSCILLATOR MEANS TO INSURE THAT THE ZERO PHASE POSITION IS MAINTAINED, INCLUDING MEANS TO COMPARE THE PHASE OF THE DATA BIT ZERO CROSSINGS AND THE PHASE OF THE TONE SIGNAL AND TO PRODUCE, AN INHIBITING SIGNAL FOR AN INCORRECT PHASE CONDITION, INHIBITING MEANS FOR SAID LOCAL OSCILLATOR MEANS RESPONSIVE TO SAID INHIBITING SIGNAL TO INTERRUPT APPLICATION OF THE SIGNAL FROM THE LOCAL OSCILLATOR FOR A TIME SUFFICIENT TO CHANGE THE PHASE OF THE SIGNAL.