Arrangement for the correct reception of binary-coded information items

摘要

967,533. Telegraphy. STANDARD TELEPHONES & CABLES Ltd. March 29, 1963 [April 5, 1962], No. 12585/63. Drawings to Specification. Heading H4P. In a telegraph system in which errors are corrected by repetition of faulty signals, each bit of a received signal is fed to a device which determines whether or not the amplitude of the bit lies within one or other of two preset ranges, corresponding to mark and space bits. Repetition is requested if the amplitude lies outside the ranges, the repetition request signal itself being checked at the main station. The system described uses an error-detecting code, and errors detected by way of the code also cause repetition. The return channel normally carries a signal having positive polarity, which indicates that the receiver has detected no error. The signal is reversed in polarity when a repetition is to be started, the transmitter receiver including a device which checks the amplitude of the return signal. Repetition is initiated if the return signal is negative or outside a preset positive amplitude range.