| 摘要 |
PROBLEM TO BE SOLVED: To obtain a periodic waveform having a period which is an integral multiple of the period of a clock with simple circuit constitution by adding data on a periodic waveform whose period is not an integral multiple of the period of the clock and correction data together. SOLUTION: A management part 1 has a counter for a master clock clk and a counter which increases its count value (n) by one when the count value (i) of the former counter varies up to N-1. A ROM 2 has f (i/T) read out by regarding (i) as an address. A ROM 3 has f'(i/T)×((N/T)-1) read out by regarding (i) as an address. Here, T is the period of a periodic waveform f'(hθ) whose period is not an integral multiple of the period of the clock clk and N is a period which is the closest to T and an integral multiple of the period of the clock clk. An arithmetic part 4 inputs data outputs S and E of the ROMs 2 and 3 and (n) from the management part 1, calculates S+E×n, and outputs the periodic waveform f (θ) having the period which is an integral multiple of the clock clk.
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