This figure shows what happens during a fast re-acquisition of the pattern when no other signals are present.  Upon detecting a PRI that may be the desired emitter, the Fade signal is brought low to indicate a valid detection. After 5 PRI (user programmed value) are processed to confirm that the track file is still valid, the PRED brings the Lock signal back high to indicate a valid track and continues the jamming process by again enabling look-through, DRFM_Write and DRFM_Read commands. 

Notice that the Stagger_position signal still reads 25 indicating that the 25-position pattern is being tracked and that fast re-acquisition process was successful.

Another point of interest is the two extended look-through periods shown in this figure.  These were caused by missing pulses (clearly visible at the same time on the Gen_Video2 trace) that were not present when the look-through occurred.  Extending the look-through allowed the PRED to continue to work through this temporary loss of signal.

Not all scans have the luxury of being re-acquired with no other emitters present; this figure shows Gen_Video2 being acquired in the presence of (the higher PRF) Gen_Video0.  Interestingly, when Gen_Video2 does return, it transmits 1 pulse then drops the second.  But as soon as the PRED is able to see a valid PRI for the signal that it had previously been tracking, Fade is brought low and the 5 PRI verification of the pattern is executed.  When this verification passes, Lock transitions high and the operation continues.  In this case, it appears as though the presence of the interfering Gen_Video0 in no way degraded the fast re-acquisition process.