Pulse frequencies are commonly between 1 and 500 MHz, corresponding to clock cycles of 1000 nsec to 2 nsec Many events may happen during a single clock cycle. This generates a secondary clock signal that is phase shifted from the primary. By tying different events to the various edges, the required sequencing can be achieved. Memory - an essential component of every computer is its memory. Without memory there could be no computers as we know them.
Memory is used for storing both instructions to be executed and data.
Unlike a combinational circuit, the outputs of the latch are not uniquely determined by the current inputs. The lower NOR gate outputs 0, the upper NOR gate outputs 1. The lower NOR gate outputs 1, the upper NOR gate outputs 0. Now examine the effect of the inputs on the state of the SR latch. This output 0 from the upper NOR gate feeds into the lower NOR gate.