<s>
After	O
performing	O
the	O
Hilbert	B-Algorithm
transform	I-Algorithm
on	O
each	O
signal	O
,	O
we	O
can	O
express	O
the	O
data	O
in	O
the	O
following	O
form	O
:	O
</s>
<s>
This	O
frequency-time	O
distribution	O
of	O
the	O
amplitude	O
is	O
designated	O
as	O
the	B-Algorithm
Hilbert	I-Algorithm
amplitude	I-Algorithm
spectrum	I-Algorithm
,	O
or	O
simply	O
Hilbert	B-Algorithm
spectrum	I-Algorithm
.	O
</s>
<s>
Hilbert	B-Algorithm
spectral	I-Algorithm
analysis	I-Algorithm
method	O
is	O
an	O
important	O
part	O
of	O
Hilbert	B-Algorithm
–	I-Algorithm
Huang	I-Algorithm
transform	I-Algorithm
.	O
</s>
