| 摘要 |
PURPOSE:To attain the reproduction to a degree that the content of sent information is comprehensible even with the deteriorated transmission C/N by sharing a high-order bit of a code subject to A/D conversion as a multi-value signal of an axis with less degree of multi-value processing and sharing the remaining low-order bits of the code subject to A/D conversion as a multi-value signal for an axis of a degree with much multi-value processing. CONSTITUTION:The degree of multi-value processing of a multi-value signal modulating respectively two-axis (Q, I) carrier orthogonal to each other respectively is made different from the Q axis as two-value and for the I axis as 4-value. Then as the multi-value signal for the Q axis with less degree of multi- value processing, the high-order bit of the code subject to A/D conversion into a required bit number is assigned and as the multi-value signal of the I axis with much degree of multi-value processing, the remaining low-order bits are assigned. Thus, even when the C/N of the transmission signal is deteriorated and most of the low-order bits is in error, the error rate of the high-order bit is less and the voice signal of some degree is to be reproduced. |
