| 摘要 |
PROBLEM TO BE SOLVED: To automatically adjust the Lissajous signal of a linear scale. SOLUTION: The signal level (peak value) of the phase A is measured and converted into a digital signal. A voltage value obtained by cutting the peak value of the digital signal voltage of the phase A undergone the analog-digital conversion by half is provided as a common level COM1. A controlling microcomputer 44 calculates the level difference between a common level COM of a reference value and the common level COM1 of the phase-A signal, and corrects an offset portion to set the common level COM and the common level COM1 in common. Then, the controlling microcomputer 44 measures the amplitude of the phase-A signal, and calculates its difference from the amplitude of the reference value, operates the variable resistor EVR1 of a gain adjuster 41 to correct it, and thus sets the amplitude of the reference value and that of a signal L1 in common.
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