| 摘要 |
PURPOSE:To make it possible to detect a speed signal stably with good response, by applying logical multiplication processing to the sum of outputs different in a phase by 90 deg. outputted by a two-phase rotary encoder and the sum of the reversed outputs to indicate a rotary direction. CONSTITUTION:The sum processing of sine wave outputs A0, B0 different in a phase by 90 deg. from a two-phase encoder and the sum processing of outputs A0, B0 through a reversal circuit 4 are performed by adders 5, 6 and, after wave form shaping, both sums are subjected to logical multiplication processing by an AND circuit 10. This logical multiplication result D comes to a signal, which indicates a sine wave signal A corresponding to a speed based on the output A0 held in a sample hold circuit 9, through a differentiation circuit 3 and speed signals different in polarity are outputted from the circuit 9 corresponding to a rotary direction. By this mechanism, the detection of a speed signal can be stably performed with good response without using a tachometer generator in the same degree as the tachometer generator. |
