Synchronisation of random bit sequences: application to hitless switching

The paper deals with the synchronisation problem of random bit sequences in hitless, or errorless, switching in frequency diversity digital radio systems. After a short discussion of technical aspects of the switching system, the problem of synchronisation is defined. The sources of incorrect operation, i.e. of not finding synchronism and of finding it in a false position, are given. It is shown that in both error free and highly erroneous situations bit sequences are synchronisable, in the statistical sense, if the delay difference is ´low´, as defined in the paper. In the noisy case an error probability lower than 0.5 is the only restriction. Statistics on the synchronisation delay and the necessary period of observation are given.<>