Abstract: A novel technique for skipping defects on a magnetic or writable optical disk is described. The technique includes a sector format comprising a header (24) and data area (28), wherein the data area can include one or more "bad areas" (108, 116) which will be skipped when data is being written to or read from the sector. The bad areas are variable in size and may be located anywhere in the data area, including in an EDAC. The header includes a defect descriptor (48) comprising a defect pointer (70, 72) for each of the bad areas supported. Each defect pointer contains a value (74, 78) indicating the number of bytes in the good data area (106, 114) preceding the bad area pointed to by the defect pointer, and a value (76, 80) indicating the number of bytes in the bad area. The value indicating the number of bytes in a good area is set to a value indicating a number of bytes at least as large as the sector size if there is no subsequent bad area in the data area.

Abstract: A magnetic disk apparatus has a magnetic head in contact with a flexible magnetic recording medium, for reading out data stored in the recording medium. The magnetic head of the apparatus is of the preceding-erase type. A converting circuit converts the output signal of the magnetic head to digital read data, and outputs it to the PLL circuit. The magnetic disk apparatus includes a preventing circuit for preventing the converting circuit from outputting to the PLL circuit the digital read data which corresponds to read out data from the DC erased areas in the tracks of said magnetic recording medium. The preventing circuit comprises an AGC amplifier for amplifying the signal read out of the magnetic head, a circuit for obtaining an envelope of the output signal of the AGC amplifier, and a circuit for preventing the converting circuit from outputting the read data when the signal level of the envelope is lower than a predetermined value.

Abstract: A video signal recording and playback apparatus and method which is applicable to wide-band recording in which a video signal is divided into a plurality of channels by time-axis expansion, and the channels are recorded in parallel on respective tracks. Prior to recording, a reference signal consisting of a plurality of different signal bursts, each having a specific frequency and each being superimposed on a specific DC level, is inserted into blanking intervals of the video signal and recorded therewith. On playback, the amplitudes of the signal bursts in the reference signal are monitored, and playback equalizers are controlled accordingly such as to maintain a predetermined equalizer characteristic and to maintain identical overall frequency characteristics for the various channels.

Abstract: A tape recorder comprising a cassette tape compartment for detachably housing a first and second cassette tapes, a capstan for driving the first and second cassette tapes coaxially mounted thereon, a mode selector member for selecting the driving mode for the first and second cassette tapes, operation means for causing the second cassette tape to perform a first or a second function and causing the first cassette tape to perform the first function, a device for allowing the second cassette tape to achieve the first or second function, in response to operation of the operation means corresponding to the first or second function, when the second cassette tape-driving mode has been selected by the mode selector member, a device for allowing the first cassette tape to achieve the first function, in response to operation of the operation means corresponding to the first function, when the first cassette tape-driving mode has been selected by the mode selector member, and a function blocking device for hindering th

Abstract: A magnetic recording playback system compatible with both an 8 mm video format and a rotary head digital audio tape form. A rotary head records tilted tracks on the tape. Each track is divided into four areas which are recorded with different types of audio signals. The signals may also be divided between adjacent tracks. Each area has its own control information. Different sampling rates are used for the two different formats.

Abstract: A recording/reproducing device for use in a floppy disk apparatus. The device has a first coil and a second coil, both wound arond a common core. The coils are connected to each other at one end, and have taps, respectively. Both coils have characteristics optimized for data-reading. A read circuit is connected to the second ends of the coils. A write circuit is connected to the taps of the coils. The write circuit writes data on a recording medium by using that portion of the first coil which extends between the tap of the first coil and the connection point between the coils, and that portion of the second coil which extends between the tap of the second coil and the connection point between the coils.

Abstract: A process for recording on a non-erasable information carrier such as a digital optical disk permitting an updating of the segmentation of the storage space of said carrier, in which a segmentation is defined by a header containing at least one header identifier and a list of segments, said segments forming a partition of said storage space, wherein for defining a new segmentation, a new header is written at the end of the most recent header, the successive headers being sequentially written into the same segment and wherein, for determining the current partition, there is a passage through the successive headers of the segment from the initial header to the most recent header.

Abstract: A synchronizing circuit for a dubbing apparatus which is capable of a dubbing a signal played back from a playback unit to a recording unit in accordance with the operation of a dubbing command key. The synchronizing circuit essentially includes a power source for supplying a driving current, a potential source associated with the dubbing command key for supplying a prescribed potential, first and second devices for setting the playback unit and the recording unit in a playback mode and a recording mode, respectively, first and second circuits for activating the first and second setting device by applying the driving current in response to the reception of the prescribed potential, respectively, and a circuit for delaying the supply of the prescribed potential to one of the first and second activating circuits when the prescribed potential is first applied to the other activating circuit.

Abstract: In an apparatus for recording and/or reproducing, in successive slant tracks on a record tape, an information signal comprised of at least an audio signal and an index signal for use in controlling transportation of the tape; the input audio signal is converted to a digitized form in which the audio data for a predetermined length of time is grouped as a plurality of data blocks which are recorded by a rotary head in a first part of a respective slant track on the tape, an index signal generator provides a coded index signal to indicate respective input information, such as, an absolute tape-position address counted from a predetermined reference position on the record tape, an index area signal is generated in predetermined timed relation to scanning by the rotary head of said first part of each slant track, and a control is responsive to the index area signal for supplying the coded index signal to a rotary head for recording by the latter in a second part of said respective slant track which is located adj

Abstract: A recording format on a recording medium comprises a data portion (4) in which a data train should be recorded. The data portion (4) comprises a user data portion (44 and 47), a check data portion (45) and resynchronizing pattern portions (46). The data train is divided into m or 4 code words, each code word being n=148 bytes. The resynchronizing pattern portions (46) are added to the data train for every m.times.3=12 bytes of data to be recorded, and serves to recover data synchronization in the event that data synchronization is missed. Each code word having a check data portion (45) is capable of correcting errors of T bytes, and errors generated in each code word by missing of data synchronization can be corrected.

Abstract: A PCM signal recording and reproducing apparatus comprises first and second memory circuits, in which PCM signals are read and written using the first memory circuit, while PCM signals stored in the second memory circuit are error-corrected. At the end of writing by the first memory circuit, the first and second memory circuits are interchanged to read the error-corrected PCM signals stored in the second memory circuit. The read-out error-corrected PCM signals are then recorded on another magnetic tape.

Abstract: An amplitude limiter circuit including first and second semiconductor elements of different conductivity types having their emitters connected with each other, first and second impedance elements connected to bases of said first and second semiconductor elements, respectivly, a switch and a capacitor connecting said first and second impedance elements, a third impedance element through which continuous oscillation is fed to the emitters of said first and second semiconductor elements, and means for applying control signal to said switch to operate said switch, thereby producing damped oscillation signal which finally reduces to zero.

Abstract: A method has been discovered for recovering data recorded on magnetic recording tape wherein adjacent layers have become adhered after long storage times, even at recommended storage conditions. The method comprises localized heating of the tape in an amount sufficient to break hydrogen (physical) bonding between the binder and the film backing. A continuous tension is applied to the tape, while withdrawing it from the spool to break residual adhesion. The spool is turned at a rate of speed sufficient to carry away heat so that the film does not reach the heat distortion temperature.