<s>
In	O
digital	O
electronics	O
,	O
a	O
synchronous	B-Application
circuit	I-Application
is	O
a	O
digital	O
circuit	O
in	O
which	O
the	O
changes	O
in	O
the	O
state	B-Application
of	O
memory	B-General_Concept
elements	O
are	O
synchronized	O
by	O
a	O
clock	O
signal	O
.	O
</s>
<s>
In	O
a	O
sequential	O
digital	O
logic	O
circuit	O
,	O
data	O
are	O
stored	O
in	O
memory	B-General_Concept
devices	I-General_Concept
called	O
flip-flops	B-General_Concept
or	O
latches	B-General_Concept
.	O
</s>
<s>
The	O
output	O
of	O
a	O
flip-flop	B-General_Concept
is	O
constant	O
until	O
a	O
pulse	O
is	O
applied	O
to	O
its	O
"	O
clock	O
"	O
input	O
,	O
upon	O
which	O
the	O
input	O
of	O
the	O
flip-flop	B-General_Concept
is	O
latched	O
into	O
its	O
output	O
.	O
</s>
<s>
In	O
a	O
synchronous	B-Application
logic	I-Application
circuit	O
,	O
an	O
electronic	O
oscillator	O
called	O
the	O
clock	O
generates	O
a	O
string	O
(	O
sequence	O
)	O
of	O
pulses	O
,	O
the	O
"	O
clock	O
signal	O
"	O
.	O
</s>
<s>
This	O
clock	O
signal	O
is	O
applied	O
to	O
every	O
storage	O
element	O
,	O
so	O
in	O
an	O
ideal	O
synchronous	B-Application
circuit	I-Application
,	O
every	O
change	O
in	O
the	O
logical	O
levels	O
of	O
its	O
storage	O
components	O
is	O
simultaneous	O
.	O
</s>
<s>
Practically	O
,	O
some	O
delay	O
is	O
required	O
for	O
each	O
logical	O
operation	O
,	O
resulting	O
in	O
a	O
maximum	O
speed	O
limitations	O
at	O
which	O
each	O
synchronous	B-Application
system	I-Application
can	O
run	O
.	O
</s>
<s>
Static	B-Application
timing	I-Application
analysis	I-Application
is	O
often	O
used	O
to	O
determine	O
the	O
maximum	O
safe	O
operating	O
speed	O
.	O
</s>
<s>
Nearly	O
all	O
digital	O
circuits	O
,	O
and	O
in	O
particular	O
nearly	O
all	O
CPUs	O
,	O
are	O
fully	O
synchronous	B-Application
circuits	I-Application
with	O
a	O
global	O
clock	O
.	O
</s>
<s>
Exceptions	O
are	O
often	O
compared	O
to	O
fully	O
synchronous	B-Application
circuits	I-Application
.	O
</s>
<s>
globally	O
asynchronous	O
locally	O
synchronous	B-Application
circuits	I-Application
,	O
</s>
<s>
and	O
fully	O
asynchronous	B-Application
circuits	I-Application
.	O
</s>
