Information reinsertion telegraphy receivers

Claim 1

IN A MULTIPLE CHANNEL FREQUENCY SHIFT KEYING RECEIVER, WHEREIN FREQUENCIES ARE RECEIVED ONE AT A TIME, WHEREIN FADING MAY OCCUR AS TO ONLY ONE FREQUENCY AT A TIME, AND WHEREIN THE FADING RATE IS FAR SLOWER THAN THE KEYING RATE, A COMPUTER SYSTEM RESPONSIVE DURING SAID FADING TO THE NON-FADING FREQUENCIES FOR GENERATING SIGNALS TIMED TO COINCIDE WITH THE FADING SIGNALS, AND WHEREIN SAID COMPUTER SYSTEM INCLUDES MEANS FOR DERIVING PULSES REPRESENTATIVE OF NON-RECEPTION OF EACH OF SAID NONFADING FREQUENCIES AND PULSES REPRESENTATIVE OF RECEPTION OF EACH OF SAID NON-FADING SIGNALS FURTHER, INCLUDES LOGIC CIRCUITRY RESPONSIVE TO SAID PULSES TO GENERATE SAID LAST NAMED SIGNALS, MEANS FOR SENSING LONG TERM ABSENCE OF A PAIR OF SAID FREQUENCIES IMPLYING AN IDLING CONDITION ON ONE OF SAID CHANNELS, MEANS FOR GENERATING A D.C. SIGNAL INDICATION OF SAID ABSENCE AND MEANS FOR INSERTING SAID D.C. SIGNAL INTO SAID LOGIC CIRCUITRY.