On 26.04.2011 9:39, anup_navy wrote:
> The problem with McBSP configuration of the compander is that
> it works only when input stream is 8 bits.

8 bits is the size of the compressor output (and the expander input), 
which complies with A- and u-law definitions. See
http://en.wikipedia.org/wiki/A-law_algorithm
http://en.wikipedia.org/wiki/%CE%9C-law_algorithm
http://en.wikipedia.org/wiki/Companding
The width of the comperessor input data stream can be different, but the 
best results are obtained if it is 16 bits. The bit stream at the 
expander output is 14- or 13-bit left-justified within a 16-bit word, 
depending on the selected companding law.

> However i wish to pass a sign
> wave and do the companding and see the results.

Did you mean a sine wave? My experience with companding is very limited, 
but AFAIK it is best suited for audio signals. What are you going to use 
companding for and what do you expect from it?

> If you can guide me thru it then it wud be grt.

Two of the links in the wikipedia article on u-law point to TI 
application notes describing both software and hardware implementations 
of companding in TMS processors.

-- 

Alexander

>Hi Alexander
            The problem with McBSP configuration of the compander is that
it works only when input stream is 8 bits. However i wish to pass a sign
wave and do the companding and see the results. If you can guide me thru it
then it wud be grt.
Thanks and regards
Anup

>>          I would be thankful to all if anyone can kindly guide me with
>>          the
>> coding of A Law and MU Law compander for TMS320C5510 in Code Composer
>> Studio. I have been stuck on this with quite a few days. Also if anyone
>> can please let me know whether some MATLAB code exists for DOA
>> estimation using Acoustic Vector Sensor where the inputs are pressure
>> and particle velocity from 3 axes.


>
> IIRC one of the Analog Devices 21xx parts had a mu-law and an A-law table
> burned into ROM for the user's convenience.
>

The same also applies to TMS320C5510. Its serial port (McBSP) has 
built-in hardware support for mu-law and A-law companding, which is 
enabled by writing certain bits in Receive and Transmit Control 
registers. See more here
http://focus.ti.com/lit/ug/spru592e/spru592e.pdf.


-- 

Alexander

On Mon, 18 Apr 2011 06:45:26 -0500, anup_navy wrote:

> Dear ALL
>         I would be thankful to all if anyone can kindly guide me with
>         the
> coding of A Law and MU Law compander for TMS320C5510 in Code Composer
> Studio. I have been stuck on this with quite a few days. Also if anyone
> can please let me know whether some MATLAB code exists for DOA
> estimation using Acoustic Vector Sensor where the inputs are pressure
> and particle velocity from 3 axes.
> Thanks and Regards
> Anup

I wouldn't know the best way to do this (other than 'google mu law and do 
what's sensible').  Have you checked the TI site for app notes?  This 
seems like a pretty likely task for a DSP, and one that I would expect 
that would be app-noted.

IIRC one of the Analog Devices 21xx parts had a mu-law and an A-law table 
burned into ROM for the user's convenience.

-- 
http://www.wescottdesign.com

Dear ALL
        I would be thankful to all if anyone can kindly guide me with the
coding of A Law and MU Law compander for TMS320C5510 in Code Composer
Studio. I have been stuck on this with quite a few days. Also if anyone can
please let me know whether some MATLAB code exists for DOA estimation using
Acoustic Vector Sensor where the inputs are pressure and particle velocity
from 3 axes.
Thanks and Regards
Anup