| 摘要 |
PURPOSE:To constitute the titled filter by one ROM by sharing the ROM written with the filter characteristic for both I and Q inputs in a table index system digital filter for a quadruple phase modulator using the ROM for a waveform shaping filter to an input data. CONSTITUTION:The sampling number of the output of a waveform shaping filter ROM 5 to two series of input data I, Q in the quadruple modulation system is used as m-time of the input data speed. Then the waveform shaping output to the two sets of data I, Q is extracted 7 in time division as the same timing data from one waveform shaping filter ROM 5, the output data is stored temporarily and the period with the next timing data is selected as 1/r and the result is subjected to interpolation 8-1, 8-2 by using (r-1) sets of data. Then digital filter output signals 10-1, 10-2 corresponding to data inputs I, Q are obtained by interleaving 9-1, 9-2 at each other interval so as to form the data I,s Q to be in the different timing from the I, Q data string after the interpolation.
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