| 摘要 |
PROBLEM TO BE SOLVED: To provide the R/D converter which can respond fast. SOLUTION: An AD converter 10 converts the sine wave output and cosine wave output of a resolver from analog to digital when the exciting sine wave of the resolver has a plus (or minus) maximum value and inputs the results to a DSP(digital signal processor) 13, which calculates a digital value according to the input data and outputs the digital value to a DA converter 11, etc. The DSP 13 calculates the angle of a rotor shaft, so the rotor shaft angle can be calculated faster than conventional technology (tracking type R/D converter) which includes a closed loop composed of a demodulating circuit, a voltage- controlled oscillator, etc., and performs a sort, of PLL control, so that a fast response can be made. The rotor shaft angle is found through digital operation, so the need for a compensating circuit for a temperature drift which was needed before for the conventional technology is eliminated, and consequently the whole constitution is therefore simplified to lower the cost.
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