IMPROVED EFFICIENCY 15-LEVEL MODIFIED DUOBINARY PRS ABOVE THE NYQUIST RATE

摘要

An improved efficiency technique for modified duobinary (class-Ⅳ) Partial-Response Signalling (PRS) above the Nyquist rate transmission is introduced.By using this technique,an increase of 4% or more above the Nyquist rate with class-Ⅳ 15-level PRS/225-QPRS,i.e.,a spectral efficiency of 6.24 b/s/Hz or more can be achieved by symbol-bysymbol detection with a small degradation,which is not feasible with the conventional method. It is further shown that with 4% increase in spectral efficiency for the improved class-Ⅳ 225-QPRS,an additional 3% of the Nyquist bandwidth can be carved out for a service channel.