[hts-users:03597] Re: HTS-demo pulsenoise

[Keiichiro Oura <uratec@xxxxxxxxxxxxxxx>]

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
>