g.728 stnd implementation

Hello friends

I am looking for information about the LD-CELP G.728 Codec.
I have download the recomendation documentation from ITU-T web site.
However, my knowleadge at digital telecommunications system is limited,
and for that I am having trouble on figuring out how this codec works just
with this recomendation file. I have also reached some books, but they only
have limited information about this codec, if any at all.
So, if anyone can point me at the right direction on the best way to
fully understand the operation of this codec, or have any kind of
resource especifically about the G.728 codec
where i can it's source code in c,if some one have it,please send me,
please help me.


.