ADPCM Be Adapted Finite
Difference PCM

At one of the systems which convert sound to the digital data,the systempart of altering PCM system. With ADPCM system, it is the same as PCM system to the place where sound is digitalizedinevery fixed time, but sound of the natural world in many cases making use of the character that, it changes continually, has decreased the data quantity without impairing the sound quality by digitalizing the difference of the data which is digitalized immediately before. With ADPCM system, withsimple PCM systemthe sound qualitywithout dropping 16 bit necessary data, it is possibleto12 bits to compress.