It was very helpful, Cat.
But my question was exactly the same that Hpasp replied. In many web articles i read stuff like: "SA-X was able to track up to Y targets..."
By that, we can suppose that the author meant that the system was able to see as many as Y targets. So it's a lie. It's also a lie if he's talking about a TWS method...

But thanks, your reply was very informative about the TWS history in soviet/russian systems, and the complementation given by Hpasp made all the information perfect.

TY