| 摘要 |
<p>Digital information is transmitted by generating coded signals inthe form of pulses on the basis of binary digital information and decoding the coded signals into the binary digital information, the pulses being coded in the time domain and being of at least two distinctly different shapes with respect to their numerical amplitude variation along the time axis of the pulses, the pulses comprising two bits of information in each pulse having energy, but coded in the way that one bit of information is in the polarity and one bit in the shape, or two bits are in the shape. Shapes containing a higher number of bits are obtained by means of distinctly different levels of amplitude. Decoding is performed by sampling along the time axis in minimum number of points. Communications systems utilizing the coding design combine the advantageous properties of the systems of the power-limited region and the systems of the bandwidth-limited region, in other words, the technique of the systems which use multiorthogonal signal constellation and the technique of the systems which use multilevel signal constellation are combined into one new class of systems with good power efficiency and good spectral efficiency. Error performance of the new class of systems is very close to the Shannon bound. The systems may be optical transmission systems, modems, radio relay systems or mobile telephone systems, all of which have increased capacity and power efficiency. The new philosophy of coding design and especially the simplicity of the decoding ensure the best performance for each particular system and permit dramatically increased traffic with high security and reliability.</p> |
