<s>
The	O
ratio	B-Algorithm
detector	I-Algorithm
is	O
a	O
type	O
of	O
detector	B-Algorithm
circuit	I-Algorithm
,	O
commonly	O
used	O
in	O
radio	O
receivers	O
for	O
demodulating	O
frequency	B-Application
modulated	I-Application
(	O
FM	B-Application
)	O
signal	O
.	O
</s>
<s>
The	O
ratio	B-Algorithm
detector	I-Algorithm
is	O
a	O
variant	O
of	O
the	O
Foster	B-Device
–	I-Device
Seeley	I-Device
discriminator	I-Device
,	O
but	O
one	O
diode	O
conducts	O
in	O
an	O
opposite	O
direction	O
,	O
and	O
using	O
a	O
tertiary	O
winding	O
in	O
the	O
preceding	O
transformer	O
.	O
</s>
<s>
The	O
ratio	B-Algorithm
detector	I-Algorithm
has	O
the	O
advantage	O
over	O
the	O
Foster	B-Device
–	I-Device
Seeley	I-Device
discriminator	I-Device
that	O
it	O
does	O
not	O
respond	O
to	O
amplitude	B-Device
modulation	I-Device
(	O
AM	O
)	O
signals	O
,	O
thus	O
potentially	O
saving	O
a	O
limiter	O
stage	O
;	O
however	O
,	O
the	O
output	O
is	O
only	O
50%	O
of	O
the	O
output	O
of	O
a	O
discriminator	O
for	O
the	O
same	O
input	O
signal	O
.	O
</s>
<s>
The	O
ratio	B-Algorithm
detector	I-Algorithm
has	O
wider	O
bandwidth	O
,	O
but	O
more	O
distortion	O
than	O
the	O
Foster	B-Device
–	I-Device
Seeley	I-Device
discriminator	I-Device
.	O
</s>
<s>
The	O
suppression	O
of	O
the	O
effect	O
of	O
amplitude	B-Application
variation	O
of	O
the	O
incoming	O
signal	O
on	O
the	O
output	O
of	O
the	O
ratio	B-Algorithm
detector	I-Algorithm
is	O
based	O
on	O
the	O
principle	O
of	O
RF	O
dynamic	O
limiting	O
:	O
</s>
<s>
As	O
the	O
amplitude	B-Application
of	O
the	O
signal	O
increases	O
,	O
the	O
higher	O
rectified	O
voltage	O
results	O
in	O
an	O
inrush	O
current	O
towards	O
the	O
reservoir	O
capacitor	O
;	O
the	O
increased	O
load	O
results	O
in	O
an	O
increased	O
damping	O
of	O
the	O
tuned	O
circuit	O
,	O
resulting	O
in	O
nearly	O
constant	O
amplitude	B-Application
on	O
the	O
output	O
despite	O
the	O
amplitude	B-Application
increase	O
of	O
the	O
incoming	O
signal	O
.	O
</s>
<s>
Similarly	O
,	O
a	O
decrease	O
in	O
the	O
input	O
signal	O
amplitude	B-Application
results	O
in	O
decreased	O
(	O
or	O
ceased	O
)	O
current	O
flow	O
towards	O
the	O
charged	O
reservoir	O
capacitor	O
,	O
resulting	O
in	O
decreased	O
-	O
or	O
no	O
damping	O
on	O
the	O
tuned	O
circuit	O
.	O
</s>
