#### amplitude summation in a spectrum

kyoon@...

Could anybody help me write a formula script that I can apply to a
spectrum object? Suppose you have a spectrum slice over a fricative
segment, what I would like to do is to divide the frequency axis (y-
axis) into a high-frequency and a low-frequency region, sum amplitude
values for each region, and calculate their ratio, so that I can see
the ratio change over time for successive spectral slices. For
example, suppose you have a 130 frequency bins in a spectrum, and the
dividing frequency is the 65th bin. Then you can sum the amplitude
values for the first 65 bins, sum the amplitude values for the rest
of the bins (66th to 130th bin), and calculate the ratio SUM
(66~130th)/SUM(1~65th). I need to look at the ratio change in order
to come up with an objective way of drawing the line between a
frication segment and the following aspiration segment in an
aspirated Korean fricative. If it works the way I intend it to, I
would be able to see a point where the ratio value crosses 1, which
can be used as the border line between the two noises.

Kyuchul Yoon
Department of Linguistics
The Ohio State University
http://ling.ohio-state.edu

Paul Boersma <paul.boersma@...>

Kyuchul Yoon wrote:

Could anybody help me write a formula script that I can apply to a
spectrum object? Suppose you have a spectrum slice over a fricative
segment, what I would like to do is to divide the frequency axis (y-
axis) into a high-frequency and a low-frequency region, sum amplitude
values for each region, and calculate their ratio, so that I can see
the ratio change over time for successive spectral slices.
Although one can indeed use a formula with things like "self+self[col-1]",
the Query menu (for a Spectrum object) contains commands like
"Get band energy" and even "Get band energy difference", which give
you the result directly.

Best wishes,
Paul
--

Paul Boersma
Institute of Phonetic Sciences, University of Amsterdam
Herengracht 338, 1016CG Amsterdam, The Netherlands
http://www.fon.hum.uva.nl/paul/
phone +31-20-5252385