<s>
An	O
electroglottographic	B-Application
wavegram	I-Application
(	O
short	O
:	O
EGG	B-Application
wavegram	I-Application
)	O
is	O
a	O
tool	O
for	O
analyzing	O
the	O
voice	O
source	O
in	O
speech	O
and	O
singing	O
,	O
based	O
on	O
electroglottographic	O
(	O
EGG	O
)	O
signals	O
(	O
and	O
their	O
first	B-Algorithm
derivative	I-Algorithm
,	O
DEGG	O
)	O
.	O
</s>
<s>
The	O
wavegram	B-Application
,	O
invented	O
by	O
Christian	O
T	O
.	O
Herbst	O
,	O
provides	O
an	O
intuitive	O
means	O
for	O
quickly	O
assessing	O
vocal	O
fold	O
contact	O
phenomena	O
and	O
their	O
variation	O
over	O
time	O
.	O
</s>
<s>
Vocal	O
fold	O
closings	O
and	O
openings	O
appear	O
here	O
as	O
a	O
sequence	O
of	O
events	O
rather	O
than	O
single	O
incidents	O
,	O
taking	O
place	O
over	O
a	O
certain	O
period	O
of	O
time	O
,	O
and	O
changing	O
with	O
pitch	O
,	O
loudness	B-Algorithm
and	O
register	O
.	O
</s>
<s>
Wavegrams	B-Application
document	O
systematic	O
phenomena	O
,	O
indicating	O
subtle	O
changes	O
of	O
the	O
vocal	O
fold	O
oscillatory	B-Algorithm
regime	O
.	O
</s>
<s>
Electroglottographic	B-Application
wavegrams	I-Application
are	O
created	O
in	O
5	O
steps	O
(	O
see	O
illustration	O
)	O
:	O
</s>
<s>
Glottal	O
cycle	O
duration	O
is	O
normalized	O
by	O
scaling	B-Algorithm
the	O
individual	O
glottal	O
cycle	O
plots	O
to	O
the	O
same	O
height	O
;	O
</s>
<s>
the	O
resulting	O
graphs	O
are	O
combined	O
to	O
form	O
the	O
final	O
display	O
,	O
the	O
EGG	B-Application
wavegram	I-Application
.	O
</s>
<s>
Wavegrams	B-Application
show	O
a	O
potential	O
to	O
be	O
used	O
in	O
:	O
</s>
<s>
To	O
construct	O
a	O
wavegram	B-Application
,	O
the	O
time-varying	O
fundamental	O
frequency	O
is	O
calculated	O
and	O
consecutive	O
individual	O
glottal	O
cycles	O
are	O
identified	O
in	O
the	O
EGG	O
or	O
DEGG	O
signal	O
.	O
</s>
<s>
The	O
idea	O
of	O
wavegrams	B-Application
can	O
be	O
extended	O
to	O
displaying	O
other	O
data	O
,	O
such	O
as	O
acoustic	O
signals	O
or	O
high-speed	O
video	O
endoscopic	B-Application
recordings	O
of	O
the	O
vibrating	O
vocal	O
folds	O
.	O
</s>
