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[HLL] CELP



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Hy !


> > I suggest you look at some of the freely available CELP codecs. They are
> > very forgiving and work at  low bit rates. [No doubt that both  properties
> > relate to the fact that these codecs have been developed by the US
> > Department  of Defense :-] The major drawback of the CELP codecs is that
> > they require more  CPU power. But the HLB should have enough.

> I don't think so, or you must know something that I don't. The CELP codecs
> I found couldn't do realtime on a 486DX4-100. More like 10% of realtime.
> You need pretty cool DSP to keep up with that. Neat codecs though. Sounded
> amazing still at 7200bps.

Our HLB uses a 30MHz/32-bit risc-cpu. This gives us about 25 Mips, i expect.
Standard-gsm needs about 10Mips (full-duplex), crypto needs about 5 Mips.
Let's have 5 Mips for everything remaining - then we use about 20 Mips.
So there is not much room left to complicate things...

It's not that we could not build an even more powerful HLB-hardware ;-)
But this would make it much more complex/expensive and should be avoided !!!
We would probably have to use 'real DSPs' again.

Does CELP usually need fixed or floating-point arithmetic ?


Volker

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