This diagram depicts a system
with n inputs (x’s), in addition to the clock, k outputs (z’s), and m binary
storage devices (q’s). Each memory device may need one or two input
signals. Many systems have only one input and one output, although we
will see examples with several of each, and some where there is no input,
other than the clock. Many memory devices provide the complemented
output (q) as well as q.