Synchronization Recovery Techniques for Binary Cyclic Codes

In serial-type d a t a transmission systems, alpha-numeric characters are ordinarily represented by groups of b i n a r y symbols. To get m e a n ingful information transfer, it is necessary at t h e receiver to correctly partition t h e incoming bit sequence, i.e., to establish and m a i n t a i n " C h a r a c t e r T i m i n g " . It is well known t h a t channel noise not only produces additive errors but also can cause timing errors; consequently, m e t h o d s to correct timing errors h a v e been suggested by m a n y authors. Usually these m e t h o d s require special coding of t h e messages, as in comma-free codes, 1 ' 2,3 ' 4 ' 6 or t h e insertion of synchronization sequences between blocks of messages. 6 A similar timing problem exists in systems where error control is employed; t h e problem is transformed f r o m character timing to word synchronization, or, equivalently, the ability to distinguish information bits f r o m check bits. Codes t h a t protect word synchronization as well * This is a part of the Ph.D. dissertation submitted by the author to the Department of Electrical Engineering, Princeton University, Princeton, N. J. 561