3. The system as defined in claim 2, wherein said separating means further includes means for subtracting the respective input code word to said DPCM decoding means from said modified line code word to obtain the respective difference code word to be supplied as an input code word to said adaptive PCM requantizing means.
2. The system as defined in claim 1, wherein said decoder further includes means for quantizing the prediction error of said DPCM decoding means and said separating means includes means for subtracting the quantized prediction error value from said respective line code word to obtain a modified line code word; and separating means means for quantizing said modified line code word in correspondence with the DPCM encoding taking place at said encoder to obtain the respective sum code word to be supplied as an input code word to said DPCM decoding means.