Abstract: A reproducing apparatus for reproducing information from recording elements formed with very small pits on a planar surface. The reproducing apparatus includes a probing unit positioned at a very small distance apart from the surface of the recording element and a scanning unit for scanning the probing unit at a very small distance apart from the surface of the recording element. The reproducing apparatus also includes a detecting unit connected to the probing unit and the recording element respectively, for detecting interactions generated between the probing unit and the surface of the recording element and a regeneration unit connected to the detecting unit for inputting a signal output from the detecting unit and for regenerating information by detecting a pattern of the pits by the input signal.

Abstract: A disk recording checking method in which recording is performed on a disk having radially different recording tracks each divided circumferentially into a plurality of sectors. The method employs a continuous writing device for continuously writing data onto a predetermined number of the sectors, and a continuous checking device for checking the data, while continuously reading the data from the predetermined number of the sectors. The method utilized checks both the number of errors in each code sequence and the total number of errors in each sector to determine if the data in the sector is valid.

Abstract: An optical magnetic memory device includes an optical magnetic recording medium such as a disc having recording magnetic film at least on one side thereof and initialized in a certain direction in advance, a recording section for recording data in such a manner that data-recorded portions and non-recorded portions are alternately formed, and a reproducing section for reproducing data from the recording medium by detecting the interval between the recorded or non-recorded portions. The reproducing section comprises a detector for detecting positive and negative peaks of signals reproduced from the recorded or non-recorded portion and a selector for selecting either of the detection outputs from the detector according to a control signal.

Abstract: A beam controller for controlling a semiconductor laser provided in an optical recording/playback apparatus includes first and second current sources for driving the semiconductor laser at a low level (play-back mode) and/or at a high level (recording or erasing mode). The first and second current sources are controlled to have stable power automatically by a first and second auto-power circuits, respectively. The first and second auto-power control circuits include a sample-hold circuit which stores an output signal from a low-pass filter. This enables the beam controller to avoid the transition response problems of the low-pass filter. A switching circuit is also included to select either the stored low-pass filter signal on the present low-pass filter signal.

Abstract: A disk recording method in which recording is performed on a disklike recording medium having a radially coaxial or spiral recording track that is divided into a predetermined plural number of recording sectors each acting as a recording unit. A predetermined number of dedicated sectors are provided at a rear portion of the recording track so that the contents that are recorded in defective sectors of the recording sectors are alternatively assigned to the dedicated sectors.

Abstract: A data modulation/demodulation system reproducing data that is divided and recorded in a plurality of blocks on a recording medium. The data modulation/demodulation system utilizes the steps of modulating the data by adding specified data bit patterns to the data bits of each block and reproducing the data which have been obtained by adding specified code bit patterns. The bit rows are independently demodulated by demodulation clocks which differ in phase. The demodulation bit pattern of the above code bit pattern which was added at the time of recording and the bit pattern which was demodulated by the different modulation clocks are compared with each other to determine which data is wrong. The correct demodulated data is selected according to this comparison and transmitted.

Abstract: A beam controller for controlling a semiconductor laser included in an optical recording-play-back apparatus. The beam controller is comprised of first and second current sources for driving the semiconductor laser at a low level during a play-back mode and at a high level during an erasing mode. The first and second current sources are respectively automatically controlled by a first and second auto-power control circuit to provide stable power outputs.

Abstract: An optical disc apparatus provided with a recording correcting system for controlling variations in the recorded bit length. The recording correcting system may be controlled not only while the apparatus is put to work, but also during unoccupied times when the recording, reproducing, and erasing operations are not required from a higher level apparatus. Also, the controlling operation may be performed so that the value of the record correction may be renewed at proper time intervals. The repetition of the correction trial at the proper interval allows a time lapse after the apparatus power-supply is put to work to occur with no undesirable effects and the characteristic variation between respective discs during the disc exchange can be coped with.

Abstract: A waveform processing circuit includes a switching circuit having first and second inputs and one output. The first input receives head portions and data portions contained in a reproduced signal from an optical head. The second input receives a level signal representing the level of the head portion or the level of the signal carrying the head portion. The switching circuit is switches between a first state in which the first input and the output are connected, and a second state in which the second input and the output are connected. A control signal producer produces a first control pulse indicating the presence of the data portion. The first control pulse is applied to the switching circuit for actuating the switching circuit to establish the first state when the first control pulse is present, and to establish the second state when the first control pulse is not present, so that the switching circuit continuously produces the signal having a level within the range of the head portion.