| 摘要 |
A pulse detection circuit receiving two encoder output signals (A, B) which are shifted in phase with each other contains rise-up detectors (20, 22), fall-down detectors (21, 23), and gates (24-31) and two or-gates (32, 33). Combining the states of the two encoder output signals (A,B) with pulses derived from the rise-up and the fall-down edges of the encoder output signals (A,B) leads to four different possible combinations of modes in one period of the encoder shaft rotation. These four combinations of modes produced during a rotation in one direction are different from those combinations produced during a rotation in the opposite direction. Counting with high accuracy will be performed even if noise is included in the encoder output signals (A, B) or if the phase relation between the two signals (A, B) is temporarily inverted. |
