RECORDING AND REPRODUCING CIRCUIT

PURPOSE:To always obtain a stable control characteristic by revising the gain of a rotation control system according to the output of a disk detection means and revising the integration constant of a stop circuit system according to the output of a disk size detection means. CONSTITUTION:The information of the presence and the size of a disk are converted into a stable DC level by level detectors 33, 34 to be inputted to a disk size detection circuit. At this time, a switch 40 is operated according to the disk size, and the deterioration in the control characteristic due to the disk size is prevented by revising a phase compensation characteristic. By a waveform shaping circuit 45, the output of a rotation detector 24 is pulse formed to be inputted to an integration circuit 46. By the level detector 48, a switch circuit 42 is opened and operated so that no brake signal is impressed to a motor when the fact that the output of the integration circuit 46 becomes a below set level is detected.