| 摘要 |
PCT No. PCT/JP85/00266 Sec. 371 Date Jan. 13, 1986 Sec. 102(e) Date Jan. 13, 1986 PCT Filed May 11, 1985 PCT Pub. No. WO85/05517 PCT Pub. Date Dec. 5, 1985.The apparatus uses at least data in the straight PCM mode and data in the differential PCM mode of second or higher orders as data based upon a sampling value of input signals, and detects and compares maximum absolute values of data of these modes. Here, the apparatus so compares that the maximum absolute value of the differential PCM mode is more weighted than the maximum absolute value of the straight PCM mode, selects the mode having the smaller maximum absolute value, and transmits the data of the selected mode in the form of digital signals. This makes it possible to suppress low-pass noise when medium-pass signals are input, to advantageously utilize the masking effect, to reduce the effect of code error, and to improve apparent SN ratio.
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