[hts-users:03919] Re: I have a question about acceleration coefficients.

[Matt Shannon <sms46@xxxxxxxxx>]

Hi Hea,

Formulae like the ones you presented are finite difference 
approximations to the first and second derivative, and are exact for 
polynomials of some order but inexact for polynomials of higher order 
and for general non-polynomial functions.  I would say that one formula 
is not really more "correct" than another, and it depends on the 
application which one will lead to a better model.

The specific window coefficients you proposed probably won't work very 
well for speech synthesis, though, since in your proposed scheme the 
even-indexed frames and the odd-indexed frames are independent, and so 
you're likely to get very discontinuous speech parameter trajectories.

Matt


On 11/11/13 00:53, Hea Young Park wrote:
> Dear all.
>
> I’m trying to build HTS with my custom voice using HTS-2.2 demo script.
>
> I have aquestion about acceleration coefficients.
>
> According to HTS book equation (5.16),
>
> The delta coefficients in time t-1, t, t+1 are computed as below.
>
> 본문 이미지 1
>
> Just then, the acceleration coefficients are computed as below.
>
> 본문 이미지 2
>
> However, according to /data/script/windows.pl <http://windows.pl> and
> /data/win/*.win3 included in HTS-2.2 demo,
>
> the acceleration coefficients are computed as below.
>
> 본문 이미지 3
>
> So, If it’s correct thatI’m thinking,
>
> /data/win/*.win3 file changed as below.
>
> Current : 3 1.0 -2.0 1.0
>
> New : 5 0.25 0.0 -0.5 0.0 0.25
>
> I just wonder whether or not what I think is correct.
>
> Please comment on my calculation mentioned above.