[hts-users:03598] Re: HTS-demo pulsenoise

[Csapo Tamas Gabor <csapot@xxxxxxxxxxx>]

Dear Keiichiro,

Thank you very much for your answer.

In the MELP standard that you cited it is written that "The pulse and 
noise excitation signals are then filtered and summed to form the mixed 
excitation." It is clear now that the voiced excitation in HTS-2.2 is a 
mix of impulses and noise. Does this mean that the HTS-2.2 normal demo 
system should be denoted / referred as 'mixed excitation' and not as 
'pulse-noise excitation'?

Best,
Tamas


2013.02.06. 4:09 keltezéssel, Keiichiro Oura írta:
> Hi,
>
> To reduce buzzy sound, low/high pass filter are used for excitation in
> HTS-2.2 normal demo scripts.
> You can check the effect by removing following line.
>
> $line .= "$DFS -b $lfil | $VOPR -a $gendir/$base.unv | ";
>
> The filter coefficients are described in
>
> Analog-to-Digital Conversion of Voice by 2,400 bit/second Mixed
> Excitation Linear Prediction (MELP). United States Department of
> Defense. Dec. 1999.
>
> Regards,
> Keiichiro Oura
>
>
> 2013/2/5 Csapo Tamas Gabor <csapot@xxxxxxxxxxx>:
> > Hi All,
> >
> > I have seen that in the HTS-2.2 Normal demo (pulse-noise excitation) some
> > noise is added above 6 kHz in the voiced regions:
> >
> > Training.pl, lines 1958 ... 1966
> >   # synthesize waveform
> >   $lfil = `$PERL $datdir/scripts/makefilter.pl $sr 0`;
> >   $hfil = `$PERL $datdir/scripts/makefilter.pl $sr 1`;
> >
> >   $line = "$SOPR -m 0 $gendir/$base.pit | $EXCITE -p $fs | $DFS -b $hfil >
> > $gendir/$base.unv";
> >   shell($line);
> >
> >   $line = "$EXCITE -p $fs $gendir/$base.pit | ";
> >   $line .= "$DFS -b $lfil | $VOPR -a $gendir/$base.unv | ";
> > [...]
> >
> > Is there any reason for adding noise to higher frequencies of the
> > pulse-noise excitation? This part of Training.pl wasn't there in the
> > HTS-2.1.1 version, and I haven't found any changelog or paper that would
> > explain why this has been introduced.
> >
> > Thanks and Best regards,
> > Tamas