Means and method of improving multiplexed transmission and reception by coding and modulating divided digital signals

DETAILED DESCRIPTION We claim: 1.
A signal transmitting apparatus comprising: an encoding means for performing error correction coding on a plurality of input signal with encoding rates in accordance with the significance of the respective input signals to generate a plurality of encoded signals, a multiplexing means for multiplexing the plurality of encoded signals in a predetermined order, and a modulating means for modulating and outputting the multiplexed encoded signals.
2.
The signal transmitting apparatus as set forth in claim 1, wherein the encoding means encodes the respective plurality of input signals such that the input signals with higher significance are encoded with smaller encoding rates, and wherein the encoding rate is the ratio of the amount of data before encoding to the amount of data after encoding.
3.
The signal transmitting apparatus as set forth in claim 2, wherein the plurality of input signals constitute one signal as a whole and are divided into a number n of input signals in accordance with their significance and, corresponding to the n input signals, the encoding means has n systems of block coding means for performing block coding on the input signals, interleaving means for interleaving the input signals subjected to the block coding, and convolutional coding means for performing convolutional coding on the interleaved input signals.
4.
The signal transmitting apparatus as set forth in claim 3, wherein the encoding rates are changed by changing the configurations of the n systems of convolutional coding means.
5.
The signal transmitting apparatus as set forth in claim 3, wherein the apparatus further has a puncturing means for puncturing the signal encoded by the convolutional coding means, and the encoding rates are changed by the puncturing.
6.
The signal transmitting apparatus as set forth in claim 2, wherein the plurality of input signals constitute one signal as a whole and are divided into a number n of input signals in accordance with their significance and, corresponding to the respective n input signals, the encoding means has n systems of means for performing block coding on the input signals, interleaving means for interleaving the input signals subjected to the block coding, and Trellis coding means for performing the Trellis coding on the interleaved input signals