1. In a data transmission system using self-clocking bi-phase coded bit streams, said bit streams having a predetermined bit period and two voltage levels with negative-going and positive-going voltage level transitions occurring in the stream to indicate clock information and data information, at least a first such voltage level transition and possibly a second voltage level transition occurring in each bit period, apparatus for recovering said information comprising: means for generating from each voltage level transition in the coded bit stream, a pulse having a first polarity, a non-retriggerable one-shot to which is applied the pulse of first polarity, said one-shot producing an output pulse having a duration that is approximately the time interval between said first and second voltage transitions and being non-retriggerable after said pulse terminates for a period of time less than the difference between the duration of a bit period and the duration of said output pulse, said output pulse providing clock information derived from the coded bit stream, and bistable storage means having a clock input to which clock information from an output of the one-shot is applied and a data input to which the coded bit stream is applied, said clock information being delayed by less than said time interval relative to any delay experienced by the coded bit stream, said bistable storage means providing at an output thereof data information decoded from the coded bit stream.