AW: lopsided tones.

["reinifrosch@xxxxxxxxxx" <reinifrosch@xxxxxxxxxx>]

Dear Randy,

My guess is that you start out with a pure-tone sound-pressure 
function of the form

p(t) = p_0 * sin(omega*t) , where omega = 2pi * 100 s^-1 ;

then you multiply all positive sound-pressure values by a factor 
of (1 + epsilon), e.g., by a factor of 1.3 . Fourier analysis then 
will yield a positive time-independent component, plus a large 
100-hertz component, A_1 * sin(omega*t), plus many small 
components of n*100 hertz, where n = 2, 3, 4, ... ; there will also 
be terms of the form B_1 * cos(omega*t) and B_n * cos(n*omega*t).

Reinhart.

Reinhart Frosch,
Dr. phil. nat.,
r. PSI and ETH Zurich,
Sommerhaldenstr. 5B,
CH-5200 Brugg.
Phone: 0041 56 441 77 72.
Mobile: 0041 79 754 30 32.
E-mail: reinifrosch@xxxxxxxxxx .

----Ursprüngliche Nachricht----
Von: rsran@xxxxxxxxxxx
Datum: 17.08.2009 21:41
An: <AUDITORY@xxxxxxxxxxxxxxx>
Betreff: lopsided tones.

Dear List,
I have been experimenting with a 100hz tone, where the positive half 
sinusoid of the period is larger than the negative, the phase is however 
is not changed. Speech seems to have this profile of larger positive 
pulses as compared to the negative, hence my interest. Applying fft to 
such a signal, I get an increase in magnitude for the 100hz component, 
and an increase in the dc component. What I hear however is the basic 
100hz tone, and a flutter on top of it, not what fft seems to indicate. 
My assumption was that the increased dc component would not be heard, 
and I would hear an increase in loudness of the 100 hz. However, the 
base 100hz loudness does not seem to change as I increase the area under 
the positive sinusoid, but the flutter does. Any history or explanation 
would be most welcome.
Thanks and regards,
Randy Randhawa