1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 2 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%2!0(94%,%2!0(G0G042!.3-)33)/.#/.$)4)/.3G0G04/G0G0“%G0G0 amended at Geneva, 1956 and 1964,Mar del Plata, 1968 and Malaga-Torremolinos, 1984)The CCITT,considering(a) that the duration of the transmitting st
2、art-stop cycle of terminal start-stop apparatus should be at least7.4 units for apparatus operating at 50 and 75 bauds, 7.5 units for apparatus operating at 100 bauds;(b) that the effective net margin should be greater than: 35% for signals sent by a transmitter having a nominal cycle equal to or gr
3、eater than 7 units (for operationat 50 or 75 bauds), 30% for signals sent by a transmitter having a nominal cycle equal to or greater than 7.2 units (foroperation at 100 bauds),unanimously declares the view(1) that regenerative repeaters for start-stop signals should operate at the nominal modulatio
4、n rate of thesignals that they are required to regenerate with a speed tolerance in service of 0.5%;(2) the effective synchronous margin should be at least 40%;(3) that the degree of synchronous start-stop distortion (see Definition 33.10, Recommendation R.140) of theretransmitted signals should not exceed 5%;(4) that the significant instants corresponding to the beginning of the start signals emitted by the regenerativerepeater should in no case be separated by less than 7 unit intervals (for operation at 50 or 75 bauds) or 7.2 unitintervals (for operation at 100 bauds).
