Can someone explain what active low and high strobes in TTL signals are?

Question

I'm working on a yig notch filter that uses TTL "active strobes" as latching functions. I understand TTL logic, but I don't know exactly what strobe signals are, so I don't know if the signals I'm looking at are correct or not.

Answer 1

The strobe (a.k.a. clock) is the signal that loads the latches. A high strobe says that the latches load data on a high level (or pos-edge) on the clock and low active strobes obviously clock the latches on low levels or falling edges. Mixing the two allows double data rate on the same data bus. Considering one bit, you can hang a pos-active and a neg-active latch on the same line. One latch will grab data on the positive edge, the other on the negative clock edge. Assuming data changes after each clock edge (with sufficient hold time) you can double the data rate for the same clock speed (a.k.a. DDR)