| 摘要 |
PURPOSE:To perform the detection of reproduction end surely by beforehand recording the signal of the specified frequency for detecting the reproduction end between the final groove and lead-out groove of a record disc. CONSTITUTION:When a pickup 2 detects the constant frequency signal having been recorded between the final groove 9 and lead-out groove 8 of a record disc 1, a monostable multi 15 and retriggerable monostable multi 14 are triggered by way of a saturation amplifier 11, integrator 12 and Schmitt trigger circuit 13. Then, the outputs of the multi 14 and of the multi 15 through inverter 16 are applied to an AND gate 17 and the reproduction end signal which conducts a transistor 18 when the multi 14 goes ON and the multi 15 goes OFF is generated from the gate 17. Hence, the reproduction end is surely detected according to the setting of the time constants of the multis 14, 15 without using any switch or the like and the separation of the pickup from the record and the like are well accomplished. |
