<s>
Admittance	B-Algorithm
parameters	I-Algorithm
or	O
Y-parameters	B-Algorithm
(	O
the	O
elements	O
of	O
an	O
admittance	O
matrix	B-Architecture
or	O
Y-matrix	O
)	O
are	O
properties	O
used	O
in	O
many	O
areas	O
of	O
electrical	O
engineering	O
,	O
such	O
as	O
power	O
,	O
electronics	O
,	O
and	O
telecommunications	O
.	O
</s>
<s>
Y	B-Algorithm
parameters	I-Algorithm
are	O
also	O
known	O
as	O
short	O
circuited	O
admittance	B-Algorithm
parameters	I-Algorithm
.	O
</s>
<s>
A	O
Y-parameter	B-Algorithm
matrix	B-Architecture
describes	O
the	O
behaviour	O
of	O
any	O
linear	O
electrical	O
network	O
that	O
can	O
be	O
regarded	O
as	O
a	O
black	B-Device
box	I-Device
with	O
a	O
number	O
of	O
ports	O
.	O
</s>
<s>
The	O
Y-matrix	O
gives	O
no	O
information	O
about	O
the	O
behaviour	O
of	O
the	O
network	O
when	O
the	O
currents	O
at	O
any	O
port	O
are	O
not	O
balanced	O
in	O
this	O
way	O
(	O
should	O
this	O
be	O
possible	O
)	O
,	O
nor	O
does	O
it	O
give	O
any	O
information	O
about	O
the	O
voltage	O
between	O
terminals	O
not	O
belonging	O
to	O
the	O
same	O
port	O
.	O
</s>
<s>
For	O
port	O
,	O
the	O
associated	O
Y-parameter	B-Algorithm
definition	O
is	O
in	O
terms	O
of	O
the	O
port	O
voltage	O
and	O
port	O
current	O
,	O
and	O
respectively	O
.	O
</s>
<s>
For	O
all	O
ports	O
the	O
currents	O
may	O
be	O
defined	O
in	O
terms	O
of	O
the	O
Y-parameter	B-Algorithm
matrix	B-Architecture
and	O
the	O
voltages	O
by	O
the	O
following	O
matrix	B-Architecture
equation	I-Architecture
:	O
</s>
<s>
where	O
Y	O
is	O
an	O
matrix	B-Architecture
the	O
elements	O
of	O
which	O
can	O
be	O
indexed	O
using	O
conventional	O
matrix	B-Architecture
notation	O
.	O
</s>
<s>
In	O
general	O
the	O
elements	O
of	O
the	O
Y-parameter	B-Algorithm
matrix	B-Architecture
are	O
complex	O
numbers	O
and	O
functions	O
of	O
frequency	O
.	O
</s>
<s>
For	O
a	O
one-port	O
network	O
,	O
the	O
Y-matrix	O
reduces	O
to	O
a	O
single	O
element	O
,	O
being	O
the	O
ordinary	O
admittance	O
measured	O
between	O
the	O
two	O
terminals	O
.	O
</s>
<s>
The	O
Y-parameter	B-Algorithm
matrix	B-Architecture
for	O
the	O
two-port	B-Algorithm
network	I-Algorithm
is	O
probably	O
the	O
most	O
common	O
.	O
</s>
<s>
In	O
this	O
case	O
the	O
relationship	O
between	O
the	O
port	O
voltages	O
,	O
port	O
currents	O
and	O
the	O
Y-parameter	B-Algorithm
matrix	B-Architecture
is	O
given	O
by	O
:	O
</s>
<s>
The	O
input	O
admittance	O
of	O
a	O
two-port	B-Algorithm
network	I-Algorithm
is	O
given	O
by	O
:	O
</s>
<s>
where	O
is	O
the	O
identity	B-Algorithm
matrix	I-Algorithm
,	O
is	O
a	O
diagonal	B-Algorithm
matrix	I-Algorithm
having	O
the	O
square	O
root	O
of	O
the	O
characteristic	O
admittance	O
(	O
the	O
reciprocal	O
of	O
the	O
characteristic	O
impedance	O
)	O
at	O
each	O
port	O
as	O
its	O
non-zero	O
elements	O
,	O
</s>
<s>
and	O
is	O
the	O
corresponding	O
diagonal	B-Algorithm
matrix	I-Algorithm
of	O
square	O
roots	O
of	O
characteristic	O
impedances	O
.	O
</s>
<s>
The	O
two-port	B-Algorithm
S-parameters	O
may	O
also	O
be	O
obtained	O
from	O
the	O
equivalent	O
two-port	B-Algorithm
Y-parameters	B-Algorithm
by	O
means	O
of	O
the	O
following	O
expressions	O
.	O
</s>
<s>
and	O
is	O
the	O
characteristic	O
impedance	O
at	O
each	O
port	O
(	O
assumed	O
the	O
same	O
for	O
the	O
two	B-Algorithm
ports	I-Algorithm
)	O
.	O
</s>
<s>
Conversion	O
from	O
Z-parameters	O
to	O
Y-parameters	B-Algorithm
is	O
much	O
simpler	O
,	O
as	O
the	O
Y-parameter	B-Algorithm
matrix	B-Architecture
is	O
just	O
the	O
inverse	O
of	O
the	O
Z-parameter	O
matrix	B-Architecture
.	O
</s>
<s>
In	O
this	O
case	O
is	O
the	O
determinant	O
of	O
the	O
Z-parameter	O
matrix	B-Architecture
.	O
</s>
