selector output on line 294 to determine whether or not a message lock or correlation has occurred channel one is always given priority i e is never locked out when a lock is not indicated pn generator 256 is preset to the epoch state of the incoming message which has been detected by the transversal correlator if the transversal correlator line 288 is high indicating correlation detection and the fts line 290 is low indicating a new message on the line then the message selector 278 output line 294 will be high triggering the channel one pn correlator 256 to synchronize to the message if the fts line 290 had been high logic one indicating that the message was already being received then the message selector output on line 294 would remain low logic zero unless the epoch detector 264 output ed 1 on line 294 was also high logic one indicating that channel one was in fact the channel receiving the message internally the message selector 278 serves to invert ed 1 at inverter 296 and the fts input at inverter 298 after which inversion the inverter 296 and 298 outputs are and 39 ed at and gate 300 with the transversal correlator output pulses and gate 302 and 39 s the transversal correlator output pulses with the non inverted ed 1 and fts pulses to derive an output which is or 39 ed with the output of and gate 300 at or gate 304 to derive the message selector 278 output as it is possible for more than one channel to simultaneously lock to the same message a priority sequence is required before describing the priority technique involved the.