| 摘要 |
PROBLEM TO BE SOLVED: To provide an F-phase signal bit lack detector for detecting a bit lack in a speed domain higher than a hitherto known upper limit of encoder rotational speed in which bit lack has been detected in an F-phase signal. SOLUTION: This F-phase signal bit lack detector is equipped with an encoder 21 for outputting rotational speed pulses corresponding to the rotational speed of a winch and F-phase signals corresponding to electrical phase angles, a BP number conversion means 22 for converting the respective F-phase signals into bit pattern (BP) numbers, a storage means 23 for storing therein a present BP number and a BP number of the encoder one sampling cycle prior thereto, a low-speed domain bit lack detection means 27 for detecting bit lack by checking a change in BP numbers before and after one sampling interval in a low speed domain, a high-speed domain bit lack detection means 28 for detecting bit lack by similarly checking a change in BP numbers in a high speed domain, and a discrimination means 25 and a switching means 26 for discriminating between a low-speed domain and a high-speed domain based on a rotational speed signal to select one of the two detection means. COPYRIGHT: (C)2005,JPO&NCIPI
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