| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide the modulator of a simpleπ/n shift n-differential phase shift keying(DPSK) at a small processing time without conducting complicated calculation such as sine, cosine functions and multiplication, addition and subtraction. SOLUTION: The device is provided with an output phase index decision device 220 which decides a current output phase index according to a table denoting cross reference a preceding output phase index and a phase change index by data obtained by parallel converting serial data string bm with a converter 210 and stores the current output phase index as the preceding output phase index and an output value decision device 230 which decides the quadrature phase component Qk and the in-phase component Ik from the output decision table according to the current output phase index. That is, the table denoting cross reference between the just preceding output phase and a phase change is used and the current output phase is decided according to the table every time the phase change is designated by input data.</p> |
