At 07:55 AM 4/3/00 +1000, you wrote:
>> -----Original Message-----
>> From: Scott Dattalo [SMTP:scott@DATTALO.COM]
>> Sent: Sunday, 2 April 2000 8:00
>> To:   PICLIST@MITVMA.MIT.EDU
>> Subject:      Re: A-law or mu-law to linear conversion.
>>
>> On Fri, 31 Mar 2000, Terry wrote:
>>
>> > Anyone know of a method to convert 8 bit A or mu-law to 16 bit linear
>> fast
>> > and compact using a 16c72?
>> > Is a lookup table the only way?
>>
>> I don't know the specifics on mu-law other than it involves logarithmic
>> compression. A quick search on the web led me to:
>>
>> http://www-s.ti.com/sc/psheets/spra267/spra267.pdf
>>
>> From which I copied this table:
>>
>>            linear                            compressed
>> 12 11 10 9  8  7  6  5  4  3  2  1  0 | 6 5 4  3  2  1  0
>> ----------------------------------------------------------
>> 0   0 0  0  0  0  0  1  Q3 Q2 Q1 Q0 x   0 0 0 Q3 Q2 Q1 Q0
>> 0   0 0  0  0  0  1  Q3 Q2 Q1 Q0  x x   0 0 1 Q3 Q2 Q1 Q0
>> 0   0 0  0  0  1  Q3 Q2 Q1 Q0  x  x x   0 1 0 Q3 Q2 Q1 Q0
>> 0   0 0  0  1  Q3 Q2 Q1 Q0  x  x  x x   0 1 1 Q3 Q2 Q1 Q0
>> 0   0 0  1  Q3 Q2 Q1 Q0  x  x  x  x x   1 0 0 Q3 Q2 Q1 Q0
>> 0   0 1  Q3 Q2 Q1 Q0  x  x  x  x  x x   1 0 1 Q3 Q2 Q1 Q0
>> 0   1 Q3 Q2 Q1 Q0  x  x  x  x  x  x x   1 1 0 Q3 Q2 Q1 Q0
>> 1  Q3 Q2 Q1 Q0  x  x  x  x  x  x  x x   1 1 1 Q3 Q2 Q1 Q0
>>
>> Is this correct?
>>
>        I don't think so A law has alternate bit inversion, and this only
>seems to have 7 bits compressed. Just remember that in the compressed for
>each bit is equal to 3dB up to 0dBmO.
>
>
>        Dennis

Dennis

It's mu-law there without the sign bit and median approximation, other then
that Scott's written a super conversion code.

Cheers
Terry