| 摘要 |
PURPOSE:To easily obtain a desired modulation output frequency by adding data of 2 series being the result of interpolation to a waveform shaping digital filter output by (m-1)-set of data while inverting the polarity at each other interval. CONSTITUTION:Input data I, Q are waveform-shaped to be a form suitable for the transmission for the frequency spectrum of a modulation output of waveform shape filters 2-1, 2-2. The output is interpolated by (m-1)-set of data so as to make the data period to 1/m by interpolation circuits 3-1, 3-2. The interpolated output is thinned out every time slot at the timing different in each I and Q side by data selection circuits 4-1, 4-2 and the polarity is inverted every one data by polarity inverting circuits 5-1, 5-2. The outputs are added by an addition circuit 6 and the result is outputted as a modulation output wave 9 via a DA conversion circuit 7 and a low pass filter 8.
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