The LNS-3901 is a 3G/HD/SD line synchronizer capable of handling hot switches between sources of the same format and phased by less than 10 lines compared to the reference. The output timing can be programmed from ½ to 10½ lines after the 0H of the reference. The reference signal can be an analog blackburst, tri-level sync or the internal URS frame reference signal provided by the REF-1801. The LNS-3901 is a very high density card. Up to 20 cards can fit in a Densité 3 frame.