Data-transmission system using binary split-phase code

A system for the transmission of binary signals, comprising:

• a first station and a second station interconnected by a communication link;
• clock means at said first station establishing a sequence of pulse cycles of predetermined duration T;
• a data source generating two-level message pulses synchronized with said clock means to coincide with said pulse cycles;
• transcoding means at said first station connected to said source and to said clock means for converting each message pulse into a pair of mutually complementary binary pulses occurring in respective half-cycles of the corresponding pulse cycle, the order of occurrence of said complementary pulses depending upon the respective message-pulse level, said transcoding means being connected to said communication link for transmitting a train of said complementary binary pulses to said second station;
• input means at said second station connected to said communication link for receiving an incoming train of said complementary binary pulses;
• delay means connected to said input means for generating a replica of said incoming train phase-shifted by T/2 with reference thereto;
• algebraic summing means connected to said input means and to said delay means for subtractively combining said incoming train and said replica thereof into a ternary pulse train with a high, a low and an intermediate pulse level, said intermediate level occurring only in the first halves of certain cycles of said incoming train;
• synchronizing means connected to said input means for establishing a series of timing pulses normally occurring during the second halves of respective cycles of said incoming train;
• and
• decision means connected to said summing means and to said synchronizing means for sampling said ternary pulse train at the instant of occurrence of each timing pulse to generate a binary pulse sequence corresponding to said message pulses.