| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect an exact rotation angle at low cost not only at low-speed rotation but also even at high-speed rotation. <P>SOLUTION: A clock output circuit 23 outputs a clock signal S1 in synchronization with a triangle wave, and a synchronous excitation signal generation circuit 8 outputs an excitation signal S2 by low-pass filtering the clock signal. A newest data creation part 24 creates cosine data Dc and sine data Ds from a cosine signal S3 and a sine signal S4 outputted from a resolver 2. A first amplitude operation part 25 obtains a cosine amplitude Lc1 and a sine amplitude Ls1 on the basis of the cosine data Dc and the sine data Ds which correspond to continuous two-time A-D conversion values. A second amplitude operation part 28 obtains a cosine amplitude Lc2 and a sine amplitude Ls2 on the basis of a difference between a cosine average value Nc and a sine average value Ns, and the newest cosine data Dc and the newest sine data Ds. A selection composing part 31 selects the cosine amplitude Lc1 and the sine amplitude Ls1 at the low-speed rotation, and selects the cosine amplitude Lc2 and the sine amplitude Ls2 at the high-speed rotation. <P>COPYRIGHT: (C)2009,JPO&INPIT |
