| 摘要 |
An apparatus for and a method of generating a pi /n-shifted n-DPSK modulation signal in a digital transfer system. Such apparatus and method are capable of determining both quadrature-phase and in-phase modulation signals from a single output value determination table. An output phase index is first determined from an output phase determination table, based on an index associated with a variation in phase occurring when serial binary data is converted into parallel data, along with a previous phase index. Based on the output phase index, a selected one of the quadrature-phase and in-phase modulation signals is determined from the output value determination table. After adjusting the output phase index, the remaining modulation signal is determined from the output value determination table. Accordingly, it is unnecessary to carry out complex calculations, such as sine function, cosine function and multiplication. In this regard, it is possible to more rapidly derive reliable modulated output signals.
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