[Speex-dev] Fwd: Re: Fixed Point on wideband-mode: Single Frame loss on 2000 Hz sine causes "freak off"

[Frank Lorenz]

I think I found the problem -- The synthesis filter has 2 poles which lie a little bit outside the unit cycle in fixed point code:

The poles are:
[ -1.00000000e+00+0.j                          1.00000000e+00+0.j
   1.21476718e-11+1.00000001j            1.21476718e-11-1.00000001j
  -1.21481991e-11+0.99999999j          -1.21481991e-11-0.99999999j
   0.00000000e+00+0.j                           0.00000000e+00+0.j
   0.00000000e+00+0.j                           0.00000000e+00+0.j        ]

Third and fourth pole have an abs(imaginary value) > 1


Now comes the interesting point: Is there an easy way to make it stable -- perhaps add a little bandwidth extension?

best regards,
Frank
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