Bernhard Holzmayer wrote:
> 
> Zach R. wrote:
> 
> > Hi,
> >   I am working with an ADSP BF533 and am experiencing a ~1.6 ms
> >   delay
> > from when the data (audio) arrives at the board to when the data
> > is
> > output from the board.  Does anyone have any experience with this
> > happening?  Is there any way to reduce (or eliminate) this delay?
> > I am just running the talkthrough example program when I have this
> > delay
> > occur (though it does happen with my other programs as well).  I
> > appreciate any help.
> >
> > Thanks,
> > Zach
> 
> I guess it's a sigma-delta codec.
> What you're experiencing is the delay which comes from the
> built-in filters on either side (ADC and DAC).
> These filters are used to suppress conversion errors (aliasing).
> Usually you cannot change this - take it as an internal system
> parameter.
> You'll find that the delay is constant and in most cases doesn't
> hurt you - except if you want to use the original signals into
> relation with those signals which passed the codec.
> If this is your problem, you could lead the original signals through
> a similar delay line to compensate this effect.
> 
> Bernhard
> --
> before sending to the above email-address:
> replace deadspam.com by foerstergroup.de

When delay is intolerable, as in servo applications, you need a
successive-approximation (or even flash!) A/D and a direct (ladder?)
A/D. If enough compute power is available for even more oversampling
than those systems normally need, an external anti-alias filter can be
primitive and prompt, or even absent. Little or no reconstruction is
needed for a motor drive.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
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Zach R. wrote:

> Hi,
>   I am working with an ADSP BF533 and am experiencing a ~1.6 ms
>   delay
> from when the data (audio) arrives at the board to when the data
> is
> output from the board.  Does anyone have any experience with this
> happening?  Is there any way to reduce (or eliminate) this delay? 
> I am just running the talkthrough example program when I have this
> delay
> occur (though it does happen with my other programs as well).  I
> appreciate any help.
> 
> Thanks,
> Zach

I guess it's a sigma-delta codec.
What you're experiencing is the delay which comes from the 
built-in filters on either side (ADC and DAC).
These filters are used to suppress conversion errors (aliasing).
Usually you cannot change this - take it as an internal system 
parameter. 
You'll find that the delay is constant and in most cases doesn't 
hurt you - except if you want to use the original signals into 
relation with those signals which passed the codec.
If this is your problem, you could lead the original signals through 
a similar delay line to compensate this effect.

Bernhard
-- 
before sending to the above email-address:
replace deadspam.com by foerstergroup.de

Hi,
  I am working with an ADSP BF533 and am experiencing a ~1.6 ms delay
from when the data (audio) arrives at the board to when the data is
output from the board.  Does anyone have any experience with this
happening?  Is there any way to reduce (or eliminate) this delay?  I
am just running the talkthrough example program when I have this delay
occur (though it does happen with my other programs as well).  I
appreciate any help.

Thanks,
Zach