Abstract: A process is disclosed for frame synchronization in a time division multiplex system which, while ensuring a high degree of synchronization reliability, requires only a small transmission capacity. In accordance with the invention, before a synchronous state is reached, a synchronization alarm (SA=1) is given and the recognition of two consecutive synchronizing words (100010) defines the beginning of a test period (P). If synchronizing words (100010) are constantly received during this test period (P), the synchronization alarm (SA=1) is disconnected. If only one single synchronizing word (100010) is not recognized during the test period (P), the synchronization alarm continues. Commencing from the synchronous state, the synchronization alarm is given if a plurality of synchronizing words are not recognized (FIGS. 3 to 6).

Abstract: A synchronization system for a time division multiplex system. Only a single synchronizing bit for each multiplex frame is transmitted, thereby reducing to a minimum the use of channel transmission capacity for synchronization purposes. Nevertheless, a synchronizing word consists of a number of successive synchronizing bits and a plurality of synchronizing words are employed in the synchronization process, so that a substantial degree of insensitivity to errors in synchronization is achieved.

Abstract: A method is described for phase regulating a received timing signal in a data transmission system wherein the transmissions contain partial response pulses. In a receiver the composite transmitted signal is reproduced, and it generally differs from certain given values. A sampling signal having amplitudes indicating these differences is produced. The sampling signal is multiplied by a factor signal to produce a multiplicative signal. The latter is integrated to produce a regulating signal used for making the aforementioned phase adjustment.