Digital quasi-impulse shaping for multi-level QAM and QPRS systems

Iwao Sasase, Li Jinxing, Kamilo Feher

Research output: Contribution to journalArticlepeer-review


Digital quasi-impulse-shaped signals for the transmission of Nyquist-shaped raised-cosine filtered signals and partial response signals are considered. Quasi-impulse signals do not require conventionally used phase-equalized x/sin(x)-shaped aperture equalizers. A simple logic circuit reduces the pulse-width of the conventional NRZ format, binary or multi-level input data. The finite pulse-width duration of these signals, as compared with the theoretically infinite impulse duration, permits a practical realization with negligible performance degradation. Experimental and computer simulation results demonstrate that pulse-widths of 25% for 225-QPRS class I, 18.75% for 64-QAM and 12.5% for 256-QAM lead to a performance degradation of only 0.2 dB at a Pe = 10-8.

Original languageEnglish
Pages (from-to)31-34
Number of pages4
JournalCanadian Journal of Electrical and Computer Engineering
Issue number1
Publication statusPublished - 1989

ASJC Scopus subject areas

  • Hardware and Architecture
  • Electrical and Electronic Engineering


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