| 摘要 |
PURPOSE:To detect always the rotative velocity of a rotating body with a high precision by detecting whether the period of the output signal of a frequency generator is between certain numerical values or not with the output circuit of a D flip flop. CONSTITUTION:If a period TFG from the rise of the output signal of a frequency generator FG9 to the rise of the next output signal of the FG9 satisfies relation T1<TFG<T2 (T1 and T2 are preliminarily set certain values), a latch means DFF latches the output of a pulse generating means RMM12 by the rise of the signal of the FG9; but if the period TFG is longer than T2, the output of a pulse generating means RMM13 becomes high-level the time T2 after the rise of the signal of the FG9, and a rotation variance detecting circuit DFF14 is reset, and its output becomes low-level. If the period TFG is between the time T1 and the time T2, an output Q of the detecting circuit 14 outputs a high-level signal indicating that photographing is possible; but if the period TFG is deviated from this range, it outputs a low-level signal indicating that photographing is impossible. Thus, the rotative velocity is detected with a high precision even after the rotating body reaches a certain rotation, and malfunctions are prevented. |
