<s>
The	O
Nichols	B-Application
plot	I-Application
is	O
a	O
plot	B-Application
used	O
in	O
signal	O
processing	O
and	O
control	O
design	O
,	O
named	O
after	O
American	O
engineer	O
Nathaniel	O
B	O
.	O
Nichols	O
.	O
</s>
<s>
the	O
Nichols	B-Application
plots	I-Application
displays	O
versus	O
.	O
</s>
<s>
This	O
plot	B-Application
may	O
be	O
compared	O
to	O
the	O
Bode	B-Algorithm
plot	I-Algorithm
in	O
which	O
the	O
two	O
inter-related	O
graphs	O
-	O
versus	O
and	O
versus	O
)	O
-	O
are	O
plotted	O
.	O
</s>
<s>
In	O
feedback	O
control	O
design	O
,	O
the	O
plot	B-Application
is	O
useful	O
for	O
assessing	O
the	O
stability	O
and	O
robustness	O
of	O
a	O
linear	O
system	O
.	O
</s>
<s>
This	O
application	O
of	O
the	O
Nichols	B-Application
plot	I-Application
is	O
central	O
to	O
the	O
quantitative	O
feedback	O
theory	O
(	O
QFT	O
)	O
of	O
Horowitz	O
and	O
Sidi	O
,	O
which	O
is	O
a	O
well	O
known	O
method	O
for	O
robust	O
control	O
system	O
design	O
.	O
</s>
<s>
Although	O
similar	O
to	O
a	O
Nyquist	B-Application
plot	I-Application
,	O
a	O
Nichols	B-Application
plot	I-Application
is	O
plotted	O
in	O
a	O
Cartesian	O
coordinate	O
system	O
while	O
a	O
Nyquist	B-Application
plot	I-Application
is	O
plotted	O
in	O
a	O
Polar	O
coordinate	O
system	O
.	O
</s>
